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2016-11-23

User Manual: Navien Navien-Npe-180A-Installation-Manual-822449

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Installation Manual
NPE Condensing Water Heaters

Model

NPE-180A
NPE-210A
NPE-240A
NPE-150S
NPE-180S
NPE-210S
NPE-240S

Keep this manual near this water heater for future reference
whenever maintenance or service is required.
* Lead Free

* The wetted surface of this product contacted by consumable water contains
less than one quarter of one percent (0.25%) of lead by weight.

WARNING
If the information in these instructions is not followed exactly, a fire or explosion may result, causing
property damage, personal injury or death.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
What to do if you smell gas
Do not try to light any appliance.
Do not touch any electrical switch; do not use any phone in your building.
Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or the gas supplier.
The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas Code,
ANSIZ223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane Installation Code.
When applicable, the installation must conform with the Manufactured Home Construction and Safety
Standard, Title 24 CFR, Part 3280 and/or CAN/CSA Z240 MH Series, Mobile Homes.

Contents

1. Safety Information

2. About the Water Heater

2.1 Items Included

2.2 Accessories

2.3 Specifications

2.4 The Front Panel

2.5 Components

2.6 Dimensions

2.7 Rating Plate

3. Installing the Water Heater

3.1 Choosing an Installation Location

3.2 Mounting the Water Heater to the Wall

3.3 Connecting the Gas Supply

3.4 Connecting the Water Supply

3.5 Connecting the Condensate Drain

3.6 Venting the Water Heater

3.7 Connecting the Power Supply

3.8 Setting the DIP Switches

4. Installing a Cascading System

4.1 Connecting Water Supplies

4.2 Connecting the Communication Cables

5. Appendixes

5.1 Gas Conversion

5.2 Technical Data

5.3 Wiring Diagram

5.4 Ladder Diagram

5.5 Component Assembly Diagrams and Parts Lists

5.6 Installation Check list

5.7 Navien ComfortAir+ Add-on Controller Kit (Optional)

5.8 Navien On-Demand Control Kit (Optional)

5.9 Requirements for the State of Massachusetts

Contents

1. Safety Information
The following safety symbols are used in this manual. Read and
follow all safety instructions in this manual precisely to avoid
unsafe operating conditions, fire, explosion, property damage,
personal injury, or death.

DANGER

DANGER
Indicates an imminently hazardous situation which, if not
avoided, could result in severe injury or death.

If you smell gas:

WARNING

Indicates a potentially hazardous situation which, if not
avoided, could result in injury or death.

CAUTION
Indicates a potentially hazardous situation which, if not
avoided, could result in property damage.

Do not try to light any appliance.
Do not touch any electrical switches or use landline phones.
From a neighbor’s phone, call your gas provider and follow
their instructions.
If you cannot reach your gas provider, call the fire
department.

Do not use or store flammable products, such as gasoline,
solvents, or adhesives in the same room or area as the
water heater.
The water heater has a main burner flame that can turn on
at any time and can ignite flammable vapors. Vapors from
flammable liquids can explode and catch fire, causing death
or severe burns.
Vapors cannot be seen and are heavier than air. They can
travel long distances along the ground and can be carried
from other rooms to the water heater’s main burner flame
by air current.
Keep all flammable products far away from the water heater
and store them in approved containers. Keep the containers
closed tightly and out of the reach of children and pets.

Safety Information

CAUTION

WARNING

Do not place combustibles, such as newspapers or
laundry, near the water heater or venting system.
Doing so may result in a fire.

Do not place or use hair sprays, spray paints, or any other
compressed gases near the water heater or venting
system, including the vent termination.
Doing so may result in fire or explosion.

Do not store or use gasoline or other flammable liquids
near this water heater.
Doing so may result in fire or explosion.

Do not operate the water heater with the front cover
opened.
Doing so may result in fire or carbon monoxide (CO)
poisoning, which may result in property damage, personal
injury, or death.

Do not operate this water heater without proper venting.
Doing so may result in fire or carbon monoxide (CO)
poisoning, which may result in property damage, personal
injury, or death.

Do not touch the power cord or internal components of
the water heater with wet hands.
Doing so may result in electric shock.

Safety Information

Do not turn on the water heater unless the water and gas
supplies are fully opened.
Doing so may damage the water heater.

Do not turn on the water if the cold water supply shutoff valve is closed.
Doing so may damage the water heater.

Do not use this water heater for anything other than its
intended purpose, as described in this manual.

Do not remove the front cover unless the power to the
water heater is turned off or disconnected.
Failure to do so may result in electric shock.

When servicing the controls, label all wires prior to
disconnecting them.
Failure to do so may result in wiring errors, which can lead to
improper or dangerous operation. Verify proper operation
after servicing.

Do not use unapproved replacement or accessory parts.
Doing so may result in improper or dangerous operation
and will void the manufacturer’s warranty.

Do not place anything in or around the vent terminals,
such as a clothes line, that could obstruct the air flow in
or out of the water heater.

This water heater has been approved for use in the USA
and Canada only.
Using the water heater in any other country will void the
manufacturer’s warranty.

2. About the Water Heater
2.1 Items Included

2.2 Accessories

When you open the box, you will find the following items with the
water heater. Check the box for each of the following items before
installing the water heater.

The following optional accessories are available for the water
heater:

Installation &
Operation Manual

Quick Installation Manual

Remote Controller

Plumb Easy Valve Set

Wall Mounting Bracket

Tapping Screws & Anchors

Pressure Relief Valve

Condensate Neutralizer

2 in Vent Termination Caps

2 in Wall Flanges

Ready-Link
Communication Cable

Outdoor Vent Kit

Conversion Kit

Spare Parts

3 in Vent Termination Caps

3 in Wall Flanges

External Pump Connector
(<150 W, 1.5 A)

Navien On-Demand /
Comfort Air+ Add-on
Controller Kit

About the Water Heater

2.3 Specifications
The following table lists the specifications for the water heater. Additional specifications about water, gas, electric, and air supplies (venting)
appear in the Installation section.
Item

NPE-150S

Heat
Capacity
(Input)

Natural Gas

Efficiency
Ratings

UEF (for NG & LP)
EF (Canada) (for NG & LP)

18,00015,000-150,000 BTU/H
120,000
15,000-150,000 BTU/H
BTU/H
0.96
0.96
0.97
0.97
0.97
0.99
6.8 GPM
8.4 GPM (32 L/m)
(25.8 L/m)
5.3 GPM
6.5 GPM (25 L/m)
(20 L/m)
3.2 GPM
4.3 GPM
4.2 GPM
(12 L/m)
(16 L/m)
(16 L/m)
17.3 in (W) x 27.4 in (H) x 13.2 in (D)
62 lbs
75 lbs
67 lbs
(28 kg)
(34 kg)
(30 kg)
Indoor or Outdoor Wall-Hung
Forced Draft Direct Vent
Electronic Ignition
15-150 PSI

Propane Gas

35 °F (19 °C) Temp Rise
Flow Rate
(DHW)

45 °F (25 °C) Temp Rise
67 °F (36 °C) Temp Rise

Dimensions
Weight
Installation Type
Venting Type
Ignition
Water Pressure
Natural Gas Supply Pressure
(from source)
Propane Gas Supply Pressure
(from source)
Natural Gas Manifold Pressure
(min-max)
Propane Gas Manifold Pressure
(min-max)
Minimum Flow Rate
Cold Water Inlet
Connection
Hot Water Outlet
Sizes
Gas Inlet
Main Supply
Power
Maximum Power
Supply
Consumption
Casing
Materials
Heat Exchangers

Venting

Safety
Devices

NPE-180A

NPE-180S

NPE-210A

NPE-210S

NPE-240A

NPE-240S

19,900-180,000 BTU/H

19,900-199,900 BTU/H

19,900-180,000 BTU/H

19,900-199,900 BTU/H

0.96
0.97

0.97
0.99

10.1 GPM (38 L/m)

11.2 GPM (42 L/m)

7.8 GPM (30 L/m)

8.7 GPM (33 L/m)

5.0 GPM
(19 L/m)

5.2 GPM
(20 L/m)

5.6 GPM
(21 L/m)

5.7 GPM
(22 L/m)

82 lbs
(37 kg)

75 lbs
(34 kg)

82 lbs
(37 kg)

75 lbs
(34 kg)

3.5 in WC-10.5 in WC
8 in WC-13 in WC
-0.04 in WC -0.04 in WC - -0.84 in WC
-0.05 in WC - -0.36 in WC
-0.40 in WC
-0.05 in WC -0.05 in WC - -0.50 in WC
-0.10 in WC - -0.66 in WC
-0.42 in WC
0 GPM (0 L/m) for “A” models / 0.5 GPM (1.9 L/m) for “S” models
3
/4 in NPT
3
/4 in NPT
3
/4 in NPT
120 V AC, 60 Hz

-0.05 in WC - -0.58 in WC
-0.10 in WC - -0.78 in WC

200 W (max 2 A), 350 W (max 4 A) with external pump connected

Cold Rolled Carbon Steel
Primary Heat Exchanger: Stainless Steel
Secondary Heat Exchanger: Stainless Steel
2 in or 3 in PVC, CPVC, Polypropylene
Exhaust
2 in or 3 in Special Gas Vent Type BH (Class II, A/B/C)
2 in or 3 in PVC, CPVC, Polypropylene
Intake
2 in or 3 in Special Gas Vent Type BH (Class II, A/B/C)
Vent Clearances
0 in to combustibles
Flame Rod, APS, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor,
Power Surge Fuse

About the Water Heater

2.4 The Front Panel
The front panel allows you to adjust the water temperature and
view the operating status or error codes. Remove the protective
sheet from the front panel before using it.
a

g
h

Error
A code will appear on the display

Master Unit
Cascade operation

b
h

Hot Water Recirculation

Display

Recirculation Mode
i

Diagnostics button
For installers only

Up button
Increases the temperature
j

Information button
Shows basic information
e

Down button
Decreases the temperature
k

Reset button
Resets the water heater (When an error occurs)

Power button
Turns the water heater on or off

Combusting
When the gas burner is on

About the Water Heater

2.5 Components
The following diagram shows the key components of the water heater. Component assembly diagrams and particular parts lists are included
in the Appendixes.

Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct

Exhaust Body

Fan Motor
Ignition Transformer
Burner

Dual Venturi

Primary Heat Exchanger

Gas Pipe

Secondary Heat Exchanger

APS (Air Pressure Sensor)

Flow Sensor

Buffer Tank

Front Panel

Circulation Pump

Condensate Trap

Gas Valve

PCB Box
Water Adjustment Valve

2-Way Valve
Gas Inlet Fitting

Water Inlet Filter
Condensate Drain Fitting

DHW Supply Fitting

Condensate Drain Lid

Recirculation Inlet Fitting

[NPE-180A/ 210A/ 240A]

About the Water Heater

Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct
Exhaust Body
Fan Motor
Ignition Transformer
Burner
Single Venturi
Primary Heat Exchanger

Gas Pipe

Secondary Heat Exchanger

Freeze Protection Switch
Front Panel

APS (Air Pressure Sensor)

Condensate Trap
PCB Box

Gas Valve

Flow Sensor
Water Adjustment Valve
Mixing Valve
Gas Inlet Fitting

Water Inlet Filter

DHW Supply Fitting

Condensate Drain Fitting

Condensate Drain Lid

[NPE-150S]

About the Water Heater

Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct

Exhaust Body

Fan Motor
Ignition Transformer
Burner

Dual Venturi

Primary Heat Exchanger

Gas Pipe
APS (Air Pressure Sensor)

Secondary Heat Exchanger

Freeze Protection Switch
Front Panel
Condensate Trap
Gas Valve

PCB Box
Flow Sensor

Water Adjustment Valve

Mixing Valve
Gas Inlet Fitting

Water Inlet Filter
Condensate Drain Fitting

DHW Supply Fitting

Condensate Drain Lid

[NPE-180S/ 210S/ 240S]

About the Water Heater

2.6 Dimensions

27.4 in (695 mm)

Supply Connections
Description

Diameter

Air Intake

2 in

Exhaust Gas Vent

2 in

Hot Water Outlet

Recirculation Inlet

Cold Water Inlet

Gas Inlet

Condensate Outlet

/4 in
/4 in
/2 in

Supply Connections
C

4.5 in (115 mm) 6.7 in (170 mm)

2.4 in (61 mm)

14.3 in (364 mm)

13.2 in (336 mm)

A
1.5 in (38 mm)

/4 in

2.6 in (67 mm)

3 in (77 mm) 0.4 in (10 mm)

Overhead View

/4 in

2.4 in (61 mm)

28.8 in (731 mm)

The following diagrams show the dimensions of the water heater and the table lists the supply connections.

2.3 in (60 mm) 3.0 in (77 mm) 8.3 in (212 mm)
17.3 in (440 mm)

[NPE-180A/ 210A/ 240A]

About the Water Heater

27.4 in (695 mm)

Air Intake

2 in

Exhaust Gas Vent

2 in

Hot Water Outlet

Cold Water Inlet

Gas Inlet

Condensate Outlet

/4 in
/4 in
/4 in
/2 in

Supply Connections

4.5 in (115 mm) 6.7 in (170 mm)

2.3 in (60 mm)

11.3 in (289 mm)
17.3 in (440 mm)

[NPE-150S/ 180S/ 210S/ 240S]

About the Water Heater

2.4 in (61 mm)

14.3 in (364 mm)

13.2 in (336 mm)

A
1.5 in (38 mm)

Diameter

2.6 in (67 mm)

3 in (77 mm) 0.4 in (10 mm)

Overhead View

Description

2.4 in (61 mm)

28.8 in (731 mm)

Supply Connections

2.7 Rating Plate
Water Heaters come from the factory configured for use with Natural Gas (NG). Before starting the installation, check the rating plate
located on the side of the water heater to ensure that the water heater matches the gas type, gas pressure, water pressure, and electrical
supply available in the installation location. If the water heater does not match each of these ratings, do not install the water heater. If
conversion to Propane Gas is required, the included gas conversion kit must be used. Refer to “5.1 Gas Conversion” for details.

Rating Plate, *Plaque Signalétique
Direct Vent Automatic Instantaneous Water Heater *Chauffe-eau instantané automatique à évent direct
For Indoor, Outdoor or Manufactured Home (Mobile Home) Installation *Pour installation dans une maison préfabriquée (mobile)
Navien, Inc.
20 Goodyear, Irvine, CA 92618
Tel: 1-800-519-8794
Model No., *Numéro de modèle
NPE-210A
Max. Input Rating, *Entrée GPL max.
180,000 Btu/h
Recovery Rating, *Calibre de recouvrement
Max. Inlet Gas Pressure, *Pression max. de gaz d’entrée
Min. Inlet Gas Pressure, *Pression min. de gaz d’entrée
Manifold Pressure, *Pression d’admission
Electrical Rating, *Régime nominal électrique
Max. Water Pressure, *Pression d’eau max.

Type of Gas, *Type de gaz
NG
Min. Input Rating, *Débit calorifique max.
19,900 Btu/h
265 Gallons/Hour, *gallons/heures
10.5 Inches W.C. *pouces W.C.
3.5 Inches W.C. *pouces W.C.
-0.36 Inches W.C. *pouces W.C.
AC *c.a. 120 Volts 60Hz, less than 2 amperes, *Utilise moins de 2A
150 psi *lb/po2
ANSI Z21.10.3 · CSA 4.3-2011

Orifices necessary for LP conversion are provided. *Les injectures nécessaires à la conversion au GPL sont fournis.
Failure to use the correct gas can cause problems which can result in death, serious injury or property damage. *Le fait de ne pas
utiliser le bon gaz peut causer des problèmes qui peuvent mener à la mort, causer des blessures graves ou endommager la propriété.
Consult your installation manual for more information. *Consultez votre manuel d’installation pour plus d’information.
Suitable for combination water (potable) heating and space heating and not suitable for space heating applications only.
*Convient au chauffage combiné de l’eau (potable) et des locaux, mais non au chauffage des locaux seulement.
This appliance is certified for use at altitudes up to 4,500 ft (1,370 m) in accordance to the latest CAN/CGA 2.17-High Altitude Installation
procedures at normal manifold pressure. For installation instructions at altitudes higher than 4,500 ft, please contact Navien. *Cet appareil
est certifié pour une utilisation à des altitudes de 0 à 4,500 pieds (1,370 m) conformément aux toutes les procédures d’installation à haute
altitude CAN/CGA 2.17 à une pression normale. Pour les installations à élévations en haut de 4,500 pieds, appeler le bureau de Navien.
This appliance must be installed in accordance with local codes, or in the absence of local codes, the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 or the CSA B149.1, Natural Gas and Propane Installation Code. *Cet appareil doit être installé selon les règlements
locaux, ou en l’absence de tels règlements, selon le National Fuel Gas Code, ANSI Z223.1/NFPA 54, ou les, Code d'installation du gaz
natural et du propane, CSA-B149.1.

FOR YOUR SAFETY *POUR VOTRE SÉCURITÉ
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other gas appliances. *Ne rangez
pas et n'utilisez pas d'essence ou d'autres liquides ou vapeurs inflammables près de cet appareil ou de tout autre appareil électroménager.

WARNING

Be sure the gas type and electricity voltage match the rating plate. Using a different gas type will cause abnormal combustion and water
heater malfunction.

Using abnormally high or low AC voltage may cause abnormal operation, and may reduce the life expectancy of this product.

About the Water Heater

3. Installing the Water Heater
3.1 Choosing an Installation Location
When choosing an installation location, you must ensure that
the location provides adequate clearance for the water heater,
adequate venting and drainage options, and sufficient access to
gas, water, and electrical supplies. Carefully consider the following
factors when choosing an installation location:
About Water Quality

Contaminant

Maximum Allowable Level

Total Hardness

Up to 200 mg/l (12 grains/gallon)

Aluminum

0.05 to 0.2 mg/l

Chloride

Up to 250 mg/l

Copper

Up to 1.0 mg/l

Iron

Up to 0.3 mg/l

Manganese

Up to 0.05 mg/l

6.5 to 8.5

Sulfate

Up to 250 mg/l

Total Dissolved Solids (TDS)

Up to 500 mg/l

Zinc

Up to 5 mg/l

Chlorine

Up to 4 mg/l

Access to utilities

Water – the installation location should be near where the
domestic water supply enters the building.
Gas – the installation location should be near where the gas
supply enters the building.
Electricity – the installation location should be near where the
electrical supply enters the building.

Installing the Water Heater

The water heater produces a significant amount of condensate

Proper maintenance of the water heater is required to ensure
that your water meets EPA quality standards. The following table
shows the maximum contaminant levels allowed, based on the
EPA National Secondary Drinking Water Regulations (40 CFR Part
143.3). If you suspect that your water is contaminated in any way,
discontinue use of the water heater and contact an authorized
technician or licensed professional.

Adequate drainage

Maintain proper clearances from any openings in the building.
Install the water heater with a minimum clearance of 12 in
(300 mm) above an exterior grade or as required by local codes.
Maintain a minimum clearance of 4 ft (1.2 m) from heating and
cooling vents.
Do not enclose the vent termination.
Install the exhaust vent in an area that is free from obstructions
and does not allow the exhaust to accumulate.
Do not install the water heater where moisture from the exhaust
may discolor or damage walls.
Do not install the water heater in bathrooms, bedrooms, or any
other occupied rooms that are normally kept closed or that are
not adequately ventilated.

Proximity to fixtures and appliances
Install the water heater near fixtures that deliver or use hot water,
such as bathroom, kitchen, and laundry room faucets. Select a
location that minimizes the water piping required between major
fixtures. If the distances are long or if the water heater requires
“instant“ hot water, we recommend running a recirculation line
back to the water heater from the furthest fixture. Insulate as
much of the hot water supply and recirculation lines as possible.
For more information about the water supply, refer to “3.4
Connecting the Water Supply“ on page 20.

Adequate installation clearances

3.2 Mounting the Water Heater to the Wall

Install the water heater in an area that allows for service and
maintenance access to utility connections, piping, filters, and traps.
Based on the installation location, ensure the following clearances
are maintained:

Navien water heaters come with an upper mounting bracket that
is pre-drilled at 16 in on center for easy installation on standard
wall studs. If the strength of the wall is insufficient or if the framing
is non-standard or uneven, reinforce the area before installing the
water heater. Avoid installation on common walls as the unit will
make some operational noises while it is running.

Clearance
from:

Indoor Installation

Outdoor Installation

Top

9 in (229 mm)
minimum

36 in (900 mm)
minimum

Back

0.5 in (20 mm)
minimum

Front

4 in (100 mm)
minimum

24 in (600 mm)
minimum

Sides

3 in (76 mm)
minimum

Bottom

12 in (300 mm)
minimum

To mount the water heater to the wall:
1. Affix the bracket securely to the wall and ensure that it is level
and that it can support the weight of the water heater.
2. Align the grooves on the back of the water heater with the
tongues on the mounting bracket and hang the water heater
on the bracket.
When mounted with the mounting bracket, the water heater
will have a 5/8 in (16 mm) clearance from the back of the wall.

Clean, debris and chemical-free combustion air

Do not install the water heater in areas where dust and debris
may accumulate or where hair sprays, spray detergents, chlorine,
or similar chemicals are used.
Do not install the water heater in areas where gasoline or other
flammables are used or stored.
Ensure that combustible materials are stored away from the
water heater and that hanging laundry or similar items do not
obstruct access to the water heater or its venting.
In commercial locations, do not install the water heater in areas
with greasy fumes or heavy amounts of steam or take measures
to prevent fumes and steam from entering the water heater.

High Elevation Installations
This water heater may be installed at elevations up to 10,100 ft
(3,078 m) for use with Natural Gas and 4,500 ft (1,370 m) for
use with Propane. Refer to “3.8.2 Setting the Front Panel DIP
Switches” on page 35 for the appropriate altitude setting.

CAUTION
Do not mount the water heater to dry wall that has not been
reinforced.

Installing the Water Heater

3.3 Connecting the Gas Supply

To connect the gas supply:
1. Determine the gas type and pressure for the water heater by
referring to the rating plate.

WARNING
2. Perform a pressure test on the main gas supply line.

Before connecting the gas supply, determine the gas type
and pressure for the water heater by referring to the rating
plate. Use only the same gas type indicated on the rating
plate. Using a different gas type will result in abnormal
combustion and malfunction of the water heater. Gas
supplies should be connected by a licensed professional
only.
The appliance and its gas connection must be leak tested
before placing the appliance in operation.
This water heater cannot be converted from natural gas
to propane or vice versa without a Navien gas conversion
kit. Do not attempt a field conversion of this water heater
without a Navien gas conversion kit. Doing so will result in
dangerous operating conditions and will void the warranty.

3. Purge the gas line of any debris.
4. Determine the proper size and type for the gas line. Refer to
the tables that follow.
5. Install full port valves on the gas supply line and water heater.
6. Connect the gas supply line.
7. Test the supply line, all connection points, and the water
heater for gas leaks.

Gas Supply

Navien recommends connecting the water heater as the first water
heater downstream of the gas meter, to ensure a sufficient gas
supply.

Pipe size : 1/2 in to 3/4 in
(inner diameter)

Gas Shutoff Valve
Union

Gas meter’s capacity ≥ Total gas
capacity of connected appliances

Gas Inlet Adapter

Gas Supply Line

Bottom View

The water heater is
recommended to be the first
appliance to be connected
to the gas supply line.

Installing the Water Heater

Note

Tighten the water heater connection valves with
care to avoid damage.

Typical LP Gas piping examples:

The gas connection fitting on all water heaters is
3
/4 in.

2 Stage System with Multiple Regulators (Recommended)

/2 in rigid pipe can be used; refer to the sizing
tables on the proceeding pages for limitations.
Avoid using 1/2 in corrugated connectors or tubing
as noise may occur.

Corrugated Connector

When using flexible gas lines, ensure that the
pipe’s inner diameter and connector is sufficient
to supply the required BTUs. Also, ensure that the
flexible line has no crimps or tight bends in it, as
this will restrict gas flow.

Gas Regulators
(2 Stage)

High Pressure Low Pressure
Regulator
Regulator
Gas Tank
Full size
Gas Pipe

When using rigid pipe, Navien recommends the
installation of a union on the gas supply line
close to the water heater, to facilitate any future
maintenance or service.

CAUTION
Prior to using an excess flow valve (EFV) in the gas line, check
the manufacturer's minimum and maximum flow capacity
rating. An improperly sized EFV wil not allow for a full flow of
gas to the water heater and may cause improper operation.

Single Regulator System

195
135
5

CLOSE:
195
MAX OPER: 135
BYPASS:
5

KBTU
/HR

CLOSE:
MAX OPER:
BYPASS:

KBTU
/HR

Gas Regulator
12 in W.C.

Pipe

Full size
Gas Pipe

Excess Flow Valve
Gas Tank

Full size
Gas Pipe

Installing the Water Heater

3.3.1 Gas Pipe Sizing Tables (Referenced from 2012 National Fuel Gas Code)
These tables are for reference only. Please consult the gas pipe manufacturer for actual pipe capacities.

Maximum Natural Gas Delivery Capacity
in Cubic Feet (ft3) per Hour (0.60 Specific Gravity; 0.5 in WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures less than 6 in WC.
Length (including fittings)
Pipe Size

10 ft
(3 m)

20 ft
(6 m)

30 ft
(9 m)

40 ft
(12 m)

50 ft
(15 m)

60 ft
(18 m)

70 ft
(21 m)

80 ft
(24 m)

90 ft
(27 m)

100 ft
(30 m)

125 ft
(38 m)

/4 in

360

247

199

170

151

137

126

117

110

104

1 in

678

466

374

320

284

257

237

220

207

195

173

1 /4 in

1,390

957

768

657

583

528

486

452

424

400

355

1 1/2 in

2,090

1,430

1,150

985

873

791

728

677

635

600

532

2 in

4,020

2,760

2,220

1,900

1,680

1,520

1,400

1,300

1,220

1,160

1,020

2 /2 in

6,400

4,400

3,530

3,020

2,680

2,430

2,230

2,080

1,950

1,840

1,630

3 in

11,300

7,780

6,250

5,350

4,740

4,290

3,950

3,670

3,450

3,260

2,890

4 in

23,100

15,900

12,700

10,900

9,660

8,760

8,050

7,490

7,030

6,640

5,890

in Cubic Feet (ft3) per Hour (0.60 Specific Gravity; 3.0 in WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures of 6 in WC or greater.
Length (including fittings)
Pipe Size

10 ft
(3 m)

20 ft
(6 m)

30 ft
(9 m)

40 ft
(12 m)

50 ft
(15 m)

60 ft
(18 m)

70 ft
(21 m)

80 ft
(24 m)

90 ft
(27 m)

100 ft
(30 m)

125 ft
(38 m)

454

312

250

214

190

172

158

147

138

131

116

/4 in

949

652

524

448

397

360

331

308

289

273

242

1 in

1,787

1,228

986

844

748

678

624

580

544

514

456

1 1/4 in

3,669

2,522

2,025

1,733

1,536

1,392

1,280

1,191

1,118

1,056

936

1 /2 in

5,497

3,778

3,034

2,597

2,302

2,085

1,919

1,785

1,675

1,582

1,402

2 in

10,588

7,277

5,844

5,001

4,433

4,016

3,695

3,437

3,225

3,046

2,700

2 1/2 in

16,875

11,598

9,314

7,971

7,065

6,401

5,889

5,479

5,140

4,856

4,303

3 in

29,832

20,503

16,465

14,092

12,489

11,316

10,411

9,685

9,087

8,584

7,608

4 in

43,678

30,020

24,107

20,632

18,286

16,569

15,243

14,181

13,305

12,568

11,139

/2 in

Installing the Water Heater

Maximum Liquefied Propane Delivery Capacity
in Thousands of BTU/H (0.5 in WC Pressure Drop)
Length (including fittings)
Pipe Size

10 ft
(3 m)

20 ft
(6 m)

30 ft
(9 m)

40 ft
(12 m)

50 ft
(15 m)

60 ft
(18 m)

80 ft
(24 m)

100 ft
(30 m)

125 ft
(38 m)

150 ft
(45 m)

175 ft
(53 m)

200 ft
(60 m)

250 ft
(76 m)

291

200

160

137

122

110

101

/4 in

608

418

336

287

255

231

212

197

185

175

155

140

129

1 in

1,150

787

632

541

480

434

400

372

349

330

292

265

243

2,350

1,620

1,300

1,110

985

892

821

763

716

677

600

543

500

1 /2 in

3,520

2,420

1,940

1,660

1,480

1,340

1,230

1,140

1,070

1,010

899

814

749

2 in

6,790

4,660

3,750

3,210

2,840

2,570

2,370

2,200

2,070

1,950

1,730

1,570

1,440

/2 in

1 /4 in

3.3.2 Measuring the Inlet Gas Pressure
WARNING
The water heater cannot function properly without sufficient inlet gas pressure. Measuring the inlet gas pressure should be performed by
a licensed professional only.

The inlet gas pressure must be maintained between 3.5 in and 10.5 in WC for natural gas and between 8.0 in and 13 in WC for liquefied
propane.
The appliance and its individual shutoff valve must be disconnected from the gas supply piping system during any pressure testing of
that system at test pressures in excess of 1/2 psi (3.5 kPa). The appliance must be isolated from the gas supply piping system by closing its
individual manual shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psi (3.5
kPa).

To measure the inlet gas pressure:
1. Shut off the manual gas valve on the gas supply line.

Opened

Closed

Gas Valve

Installing the Water Heater

2. Open a hot water faucet. The water heater should turn on and
the gas in the gas supply line will be purged.

8. When the water heater reaches its maximum firing rate, check
the inlet gas pressure reading on the manometer. The gas
pressure must fall within the ranges specified on page 19.

3. Leave the faucet on until the water heater shuts down due to a
lack of gas supply, and then turn off the hot water faucet.
4. Remove the water heater front cover by loosening the
4 Phillips head screws securing it to the case.

3.4 Connecting the Water Supply

5. Loosen the screw indicated in the figure below and connect a
manometer to the pressure port. Reset the manometer to zero
before use.

The water fittings on the water heater are 3/4 in. If the installation
site only has 1/2 in plumbing throughout, it is not necessary to
upsize the water lines to 3/4 in, if you are installing a single water
heater. When installing multiple water heaters, the number of
water heaters and pipe sizing required will depend on the total
hot water demand. For information about pipe sizing for multiple
water heaters, refer to "4.1.1 Piping Sizes and Considerations" on
page 38.
When connecting the water supply, follow these guidelines:

Digital pressure
manometer

6. Re-open the manual gas valve and check for leaks.
7. Open multiple fixtures that have high flow rates, such as
bathtub and shower faucets, to ramp the water heater up to its
maximum firing rate.

Installing the Water Heater

Do not remove the factory installed recirculation inlet cap unless
a return line is connected to this fitting. Water leakage will occur
if this cap is loose or missing ("A" model only).
Use only pipes, fittings, valves, and other components, such as
solder, that are approved for use in potable water systems.
Tighten the water heater connection valves with care to avoid
damage.
We recommend using unions and manual shut-off valves on the
cold water inlet, DHW outlet, and recirculation water inlet.
Strive to make the hot water piping system as short as possible,
to deliver hot water to the fixtures more quickly.
To conserve water and energy, insulate all water piping—
especially the hot and recirculation water lines. Never cover the
drain or pressure relief valve. If the water heater is installed in
a closed water supply system, such as one having a backflow
preventer in the cold water supply line, means shall be provided
to control thermal expansion. Contact the water supplier or local
plumbing inspector for information about how to control this
situation.
After installing the water heater, clean the inlet water filter that
is located inside the cold water inlet, and then test the water
heater for proper flow and inspect for leaks. Instruct the water
heater owner that the filter must be cleaned periodically to
maintain proper water flow.

The following is a typical water piping example for NPE-180A/
210A/ 240A models.

3.4.1 Using the Water Heater for Combination
Water Heating and Space Heating
When using the water heater for both water (potable) heating and
space heating, follow these guidelines:

Pressure
Relief Valve

Union
Full port
Gas Valve

Shutoff Valve
Gas Supply

Condensate Drain

Hot Water Supply
Cold Water
Supply
Recirculation Line

CAUTION

Expansion
Tank

Do not configure the system for DHW recirculation when it is
configured to run an air handler using the ComfortAir+ addon controller. DHW recirculation and Navien ComfortAir+
configurations cannot be used at the same time.

[NPE-180A/ 210A/ 240A]

Ensure that all piping and components connected the water
heater are suitable for potable water applications.
Do not introduce toxic chemicals, such as boiler treatments, into
the potable water.
On Combi applications, circulators suitable for DHW applications
must be used.
Do not connect the water heater to any heating systems or
components that have been previously used with non-potable
water heaters.
If the system requires varying temperatures for water—for
example, hotter water for space heating than for other uses—
install a mixing valve to temper the water and reduce the
potential for scalding.
Do not use the water heater for space heating only.
Make sure circulator flow rate through the Water Heater does
not exceed 4 GPM.

The following is a typical water piping example for NPE-180S/
210S/ 240S models.

3.4.2 Selecting a Recirculation Mode ("A" model
only)
On all “A“ model Navien water heaters, you can choose from
two pre-heating modes: internal recirculation mode or external
recirculation mode. To select a recirculation mode, you must set
the DIP switches on the front panel, and set the position of the
2-way valve inside the water heater. By default, the DIP switches
are set to OFF.

Union

Pressure
Relief Valve

Full port
Gas Valve

Shutoff Valve

Gas Supply
Condensate Drain
Cold Water
Supply

Hot Water
Supply

When you use a recirculation mode, there will be some minor
efficiency loss, as a result of the water heater maintaining a steady
temperature within the circulation loop. Although in many cases,
higher gas usage will be made up for by lower water usage.
The recirculation feature of the “A“ models has three performance
advantages:

Elimination of any minimum flow rate requirement.
Elimination of any hot/cold/hot stacking—the “cold water
sandwich“ effect.
Quicker hot water delivery to fixtures, which results in less water
wasted.

[NPE-150S/ 180S/ 210S/ 240S]

Installing the Water Heater

Note

When using external recirculation mode with the
built-in pump, observe the following maximum
recirculation pipe lengths including fittings (3/4 in pipe
is recommended):
-1/2 in Copper Pipe- 100 ft (30 m) of equivalent length
-3/4 in Copper Pipe- 500 ft (150 m) of equivalent length
Lengths in excess of these limits will require an
external recirculation pump.

CAUTION
Do not remove recirculation cap. (Internal Recirculation Mode)

The following diagram shows the internal recirculation flow for
pre-heating:

Internal Recirculation Mode
Primary Heat Exchanger

To use the internal recirculation mode:
1. Connect the water supply.
2. Set the 2-way valve inside the water heater to “INT.“

Buffer
Tank

Secondary Heat Exchanger

2-Way
Valve

Circulation
Pump

Open

Flow
Sensor

Check
Valve

Water
Adjustment
Valve

Hot Water
Supply

Domestic Water
Supply
Internal Recirculation Mode

3. Set the front panel DIP switches at the far left (set of ten) to:
1—ON; 2—OFF.

External Recirculation Mode
To use the external recirculation mode:
1. Connect the water supply to support recirculation. Refer to the
"[NPE-180A/ 210A/ 240A]" diagram on page 21.
2. Set the 2-way valve inside the water heater to “EXT.“

Installing the Water Heater

3. Set the front panel DIP switches at the far left (set of ten) to:
1—OFF; 2—ON.

3.4.3 External Pump Wire Connection
An external pump may be connected to the water heater for
recirculation applications. When selecting a circulator, it shall be
sized to maintain a flow of 2-4 GPM through the water heater.
Follow the instructions below when connecting the pump wire
accessory to the PCB.

WARNING
Failure to follow the instructions below may result in property
damage, personal injury or death. To avoid the danger of
electric shock, make sure that the water heater is turned off
before connecting the wire to the PCB.

Maximum Power Consumption: 150 W, 1.5 A
Length: 6 ft (183 cm)

Ú When using a pump with larger power requirements than the listed

specication above, a relay should be used to ensure proper operation.
1

1. Remove the water heater front cover by loosening the
4 Phillips head screws securing it to the case.

The following diagram shows the external recirculation flow for
pre-heating:

Primary Heat Exchanger

Buffer
Tank

Secondary Heat Exchanger

2-Way
Valve

Circulation
Pump

2. Locate the power switch on the right side of the front panel
and switch the system off.

Water
Adjustment
Valve

Closed

Hot
Water
Supply

Flow
Sensor

Check
Valve

Recirculation
Water Supply

Domestic
Water
Supply

Turn the switch off.
External Recirculation Mode

Installing the Water Heater

3. Remove the 2 screws holding the PCB box in place and remove
the PCB box from the system.

8. Locate the 10-switch DIP (SW1) on the front panel and turn on
the proper switches based on the desired recirculation setting
(see Recirculation Dipswitch Settings below).

Remove Screws here.
1

4. Connect the external pump wiring connector to the connector
socket on the PCB (TB1).

9. Turn on the switch beside the front panel.

TB1

10. Put the water heater cover back on and secure it with the
4 screws.

5. Put the PCB box back in its original place and secure it using
the 2 mounting screws.
6. Remove the plastic insulation from the external pump wire
with a wire stripper before connecting it to the pump.
G

Condensate
Gas

Domestic
Hot Water

Domestic
Cold Water
Domestic
Recirculation
Return

7. Connect the External Pump Wire to the proper wires from the
pump junction box.

WARNING
To avoid the danger of electric shock, turn on the water heater
ONLY after connecting the wire to the external pump.

Installing the Water Heater

Recirculation Using External Pump Only

To complete the installation of the water heater, you must install
an approved 3/4 in, maximum 150 PSI pressure relief valve on the
hot water outlet. The water heater has a built-in high temperature
shut off switch, so install a “pressure only“ relief valve. This valve is
not supplied, but is required. The following examples are approved
for use with the water heater:

Wilkins P-1000A (Zurn Industries)
Conbraco 17-402-04
Watts Industries 3L(M7)
Cash Acme FWL-2, 3/4 in

The pressure relief valve should be placed as close to the water
heater as possible. No other valve should be placed between the
pressure relief valve and the water heater.
Condensate
Gas
Domestic
Cold Water

Domestic
Hot Water

Pressure
relief valve

Domestic
Recirculation
Return

Recirculation Using Two Pumps
(Navien Internal Pump & External Pump)
Shut-off Valve
Gas

Hot water

Cold water

3.4.4 Connecting a Pressure Relief Valve
When installing the valve, follow these guidelines:

WARNING
Improper installation of the pressure relief valve may result
in property damage, personal injury, or death. Follow all
instructions and guidelines when installing the pressure
relief valve. The valve should be installed only by a licensed
professional.

Ensure that the discharge capacity of the pressure relief valve
is equal to or greater than the maximum pressure rating of the
water heater.
Ensure that the maximum BTU/H rating on the pressure relief
valve is equal to or greater than the maximum input BTU/H
rating of the water heater.
Direct the discharge piping of the pressure relief valve so that
hot water will not splash on anyone or any nearby equipment.
Attach the discharge line to the pressure relief valve and run the
end of the line to within 6-12 in (150-300 mm) of the floor.
Ensure that the discharge line will allow free and complete
drainage without restriction. Do not install a reducing coupling
or other restriction on the discharge line.
If the relief valve discharges periodically, this may be due to
thermal expansion in a closed water supply system. Contact the
water supplier or local plumbing inspector on how to correct
this situation. Do not plug the relief valve.

Installing the Water Heater

3.5 Connecting the Condensate Drain
The Navien Condensing Water Heater creates condensation when
it operates. This condensation has an acidic pH of 3-5. Follow all
local codes and regulations when disposing of condensate from
the water heater. We recommend draining the condensate into
a laundry tub, as the alkali in laundry detergent will neutralize
the acid in the condensate. However, other suitable waste drain
locations may be used according to local codes.

CAUTION

a. From the water heater directly into an external drain.
b. From the water heater, through a neutralizing agent, and then
into an external drain.
Note

If you choose this option, the neutralizing agent
must be replaced periodically. Depletion of the
neutralizing agent will vary, based on the usage
rate of the water heater. During the first year of
operation, the neutralizer should be checked every
few months for depletion and replaced as needed.

c. From the water heater into a laundry tub.

Do not cap or plug the integrated condensate line. If
prevented from draining, condensate can damage the water
heater.

The condensate line must have a negative slope to drain
properly.

Before connecting the condensate drain, choose one of the
following disposal options:

Note

The bottom of the water heater must be higher
than the top of the laundry tub to use this option.
The condensate line must have a negative slope to
drain properly.

d. From the water heater into a condensate pump, and then into a
laundry tub.
Note

A pump can be used when there is a long distance
between the water heater and the laundry tub or
when the bottom of the water heater is lower than
the top of the laundry tub.

To connect the condensate drain:
1. Connect a drain line to the 1/2 in fitting at the bottom of the
water heater.
Use only corrosion-resistant material for the drain line, such as
PVC or CPVC. Do not reduce the size of this fitting or the drain
line to less than 1/2 in.

Direct to the
external drain
To the
drain via a
neutralizer

To the
laundry tub

NPT 1/2 in

External drain

To the laundry tub via
a condensate pump

2. Place the free end of the drain line into an appropriate drain.
3. If you are using a condensate pump, ensure that the pump
allows for up to 2 GPH of drainage for each water heater in the
system.
If you are not using a condensate pump, ensure that the drain
line is pitched downward at a minimum slope of 1/4 in per foot.

Installing the Water Heater

3.5.1 Condensate Neutralizer Kit
WARNING

To avoid damaging the appliance, the neutralizer inlet and
discharge must be lower than the condensate drain.

Do NOT allow exhaust flue gases to vent through the
neutralizer. Leakage can cause injury or death from carbon
monoxide.

The connection between the appliance and the neutralizer
must be installed to prevent the backflow of condensate
into the appliance.

Do not connect more than one appliance to the neutralizer.

Optional
overflow bypass

If option 'b' is selected for condensate disposal, the Navien
condensate neutralizer kit is recommended. The condensate from
the appliance flows through the neutralizing media and increases
the pH of the condensate. An increased pH prevents corrosion of
the installation's drainage system and the public sewer system.

Figure 1. Horizontal installation

Installation

The inlet has a center connection port and the outlet has an
offset connection.
Install the neutralizer on the wall or the floor and secure it using
the brackets supplied with the kit.
If the neutralizer is installed horizontally, rotate the neutralizer to
position the outlet at the highest point (Figure 1).
If the neutralizer is mounted vertically, ensure that the outlet is
higher than the inlet (Figure 2).
Ensure that the condensate runs freely to the drain.
Ensure all connections are made to prevent the backflow of
condensate. Use corrosion resistant piping and secure all piping
to prevent movement.
Note

Optional
overflow bypass

Do not install condensate piping in areas where the
temperature drops below freezing point. Protect piping
in high pedestrian areas from damage and vibration.

For increased safety when the condensate drain blocks, install
a Y-fitting. Connect the Y-fitting as shown in the installation
diagram and ensure that the condensate runs freely to the drain.
Ensure that the discharge connection is accessible. Access to
the discharge connection is required for maintenance and pH
testing.
If there is insufficient gradient for drainage, install a drainage
pump designed for boiler and water heater condensate removal.

Figure 2. Vertical installation

Maintenance
Periodically monitor the level of media in the neutralizer and test
the pH level at the outlet. We recommend an annual pH test using
recognized test strips or an electronic pH meter to obtain precise
measurements. Replace the neutralizing media when the pH drops
below the minimum level required by the local water authority. If
the pH level is not specified, replace the neutralizing media when
the pH is below 6.0. For replacement media, contact your local
Navien distributor.

Installing the Water Heater

3.6 Venting the Water Heater

WARNING
Improper venting of the water heater can result in excessive
levels of carbon monoxide, which can lead to severe personal
injury or death. This water heater must be vented in
accordance with the “Venting of Equipment“ section of
the latest edition of the ANSI Z223.1/NFPA 54 Natural Fuel
Gas Code in the USA and/or the “Venting systems and air
supply for water heaters“ section of the latest version of
the CAN/CGA B149.1 Natural Gas and Propane Installation
Code in Canada, as well as all applicable local building
codes and regulations. Follow all instructions and guidelines
when venting the water heater. Venting should be performed
only by a licensed professional.

The water heater must be properly vented to ensure a constant
supply of clean intake air and to ensure that exhaust air is properly
removed from living areas. When venting the water heater, follow
these guidelines:

Do not install the water heater in areas with contaminated air
(containing a high level of dust, sawdust, sand, flour, aerosols,
or any other such airborne contaminants), as contaminants
can cause operational problems. The warranty does not cover
damage caused by contaminants in the installation area. If you
must install the water heater in an area with contaminated air,
use direct venting to supply air from outside the building. We
recommend regular filter cleaning and maintenance in these
areas.
For best results, keep the venting system as short and straight as
possible.
Locate the water heater as close as possible to the vent
termination.
Do not connect the water heater vent to a vent for any other gas
water heater or vent stack.
For horizontal runs, slope the horizontal section upward toward
the vent termination at a rate of 1/4 in per foot (2 % slope).
Create an airtight seal at each joint in the exhaust and intake air
pipes from the water heater collar to the vent termination.
To avoid moisture and frost build-up and to maintain clearances
to openings on adjacent homes, 45° elbows, 90° elbows, or tees
may be attached to the end of the termination vent pipe to
direct the exhaust plumes away from buildings, as long as the
total allowable vent lengths, maximum number of elbows, and
distances to air intake restrictions are observed.

Installing the Water Heater

Do not store hazardous or flammable substances near the vent
termination.
If this water heater will be installed in areas where snow is
known to accumulate, protect the vent termination from
blockage.
Ensure that the vent termination is at least 12 in (305 mm) above
ground, or as required by local codes.
Support the vent pipe with hangers at regular intervals or as
required by local codes.
Exhaust and intake air pipes must be supported at least every 4
ft (1.2 m).
The vent for this appliance shall not terminate over public
walkways; or near soffit vents or crawl space vents or where
condensate or vapor could create a nuisance or hazard or cause
property damage; or where condensate or vapor could cause
damage or could be detrimental to the operation of regulators,
relief valves, or other equipment.

3.6.1 Selecting a Vent Type
All water heaters are prepared at the factory to be direct vent
(sealed combustion) water heaters that draw all of their required
combustion air directly from outside the building. Navien
recommends direct air vent installations whenever possible to
avoid back drafting cold air through the water heater. If you cannot
use a direct vent, ensure that an ample supply of make-up air is
available in the installation location.
Navien also recommends installing a new vent system with this
appliance. If reusing an existing vent system, thoroughly inspect
it for punctures, cracks, or blockages prior to connecting it to the
water heater.
Direct Venting
The water heater uses 2 in or 3 in diameter exhaust and 2 in or 3
in diameter intake air ducts. To ensure the draw of air directly from
and exhaust of air directly to the outside of the building, create an
airtight seal from the water heater collar to the vent termination.
Intake materials can be made of ABS, PVC, CPVC, PP, galvanized
steel, corrugated aluminum or any other such materials. If you
use a corrugated material, ensure that there is not inadvertent
crimping of, or damage to, the intake air pipe.
When using direct venting, maintain the following venting
clearances, as required by ANSI Z21.10.3 and the National Fuel
Gas Code, ANSI Z223.1/NFPA 54, and CAN/CGA B149.1 Natural
Gas and Propane Installation Code:

Description

Canadian Direct Vent Installations1

US Direct Vent Installations2

Clearance above grade, veranda, porch, deck, or balcony

12 in (30 cm)

Clearance to window or door that may be opened

36 in (91 cm)

12 in (30 cm)

Clearance to permanently closed window

Vertical clearance to ventilated soffit located above the
terminal within a horizontal distance of 2 ft (61 cm) from
the center line of the terminal

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line extended above
meter/regulator assembly

3 ft (91 cm) within a height 15
ft above the meter/regulator
assembly

Clearance to service regulator vent outlet

3 ft (91 cm)

Clearance to nonmechanical air supply inlet to building
or the combustion air inlet to any other appliance

36 in (91 cm)

12 in (30 cm)

Clearance to a mechanical air supply inlet

6 ft (1.83 m)

3 ft (91 cm) above if within 10
ft (3 m) horizontally

Clearance above paved sidewalk or paved driveway
located on public property

7 ft (2.13 m) †

Clearance under veranda, porch deck, or balcony

12 in (30 cm) ‡

Ref

1 In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2 In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier.

Installing the Water Heater

Non-Direct Venting (Single Pipe)
If, at any time, the installation location could experience negative
pressure, there is a possibility of back drafting cold air through
the water heater’s heat exchanger. This situation could lead to
the freezing of the heat exchanger and malfunction of the water
heater.
However, building codes in most jurisdictions disallow negative
pressures in residences. In a home with a well-balanced air supply,
the heat exchanger should not be in danger of freezing. Because
the cause of back drafting is not considered a manufacturing
problem, any freezing damage which occurs from back drafting
will not be covered by the Navien warranty. If there is any question
about the possibility of back drafting in the installation location,
use a direct venting system for the water heater.
When installed in a manufactured home (mobile home), all
combustion air must be supplied from the outdoors as described
on page 28.
When using non-direct venting, maintain non-direct vent
clearances shown on page 31 as required by ANSI Z21.10.3 and
the National Fuel Gas Code, ANSI Z223.1/NFPA 54, and CAN/
CSA B149.1 Natural Gas And Propane Installation Code.

2. Provide two openings to allow for circulation of combustion air
as specified by ANSI Z223.1/NFPA 54 or CAN/CGA B-149.1:

NPE-150S

NPE-180A
NPE-180S

NPE-210A
NPE-210S

Maximum
Input
(BTU/H)

Outdoor
make up air is
provided,
a minimum
free area of
1 in2 per 4,000
BTU/H

Indoor make
up air is
provided,
a minimum
free area of
1 in2 per 1,000
BTU/H

120,000

30 in2
10 in (W) x 3 in
(H) or 6 in
round

120 in2
11 in (W) x
11 in (H)

150,000

40 in2
10 in (W) x 4 in
(H) or 7 in
round

150 in2
12 1/4 in (W) x
12 1/4 in (H)

180,000

45 in2
10 in (W) x 5 in
(H) or 8 in
round

180 in2
13 1/4 in (W) x
13 1/4 in (H)

199,900

50 in2
10 in (W) x 5 in
(H) or 8 in
round

199 in2
14 1/4 in (W) x
14 1/4 in (H)

To use non-direct venting for the water heater:
1. Insert the termination end cap into the intake air duct. Do not
glue the end cap, to allow for easy removal and cleaning of the
cap.

Vent termination cap 2 in
Coupling 2 in
Pipe 2 in

Installing the Water Heater

NPE-240A
NPE-240S

Description

Canadian Non-Direct Vent
Installations1

US Non-Direct Vent
Installations2

Clearance above grade, veranda, porch, deck, or balcony

12 in (30 cm)

Clearance to window or door that may be opened

36 in (91 cm)

48 in (120 cm) below or to side
of opening; 12 in (30 cm) above
opening

Clearance to permanently closed window

Vertical clearance to ventilated soffit located above the
terminal within a horizontal distance of 2 ft (61 cm) from
the center line of the terminal

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line extended above
meter/regulator assembly

36 in (91 cm) within a height
15 ft (4.57 m) above the meter/
regulator assembly

Clearance to service regulator vent outlet

36 in (91 cm)

Clearance to nonmechanical air supply inlet to building or
the combustion air inlet to any other appliance

36 in (91 cm)

48 in (120 cm) below or to side
of opening; 12 in (30 cm) above
opening

Clearance to a mechanical air supply inlet

6 ft (1.83 m)

36 in (91 cm) above if within 10 ft
(3 m) horizontally

Clearance above paved sidewalk or paved driveway
located on public property

7 ft (2.13 m) †

Clearance under veranda, porch deck, or balcony

12 in (30 cm) ‡

Ref

Installing the Water Heater

3.6.2 Selecting Vent Pipe Materials

3.6.3 Measuring Vent Length

Venting requirements differ in the US and Canada. Consult the
following chart or the most recent edition of ANSI Z223.1/NFPA
54 or CAN/CGA B149.1, as well as all applicable local codes and
regulations when selecting vent pipe materials. Do not use cellular
core based pipe materials for the exhaust vent.

The maximum vent length when using 2 in exhaust ducts is 60 ft.
The maximum vent length when using 3 in vent ducts is 150 ft.
The intake duct length can be of equal length to the exhaust duct
length. Both maximum lengths are reduced by the number of
elbows used, as shown in the following table:

Locale

Recommended Vent Materials

USA

Canada**

Maximum
Length

Vent Size

PVC Schedule 40 (Solid Core)
CPVC Schedule 40 or 80 (Solid Core)
Approved Polypropylene*
Type BH Special Gas Vent Class IIA (PVC)
Type BH Special Gas Vent Class IIB (CPVC)
Type BH Special Gas Vent Class IIC
(Polypropylene)

60 ft
(18 m)

2 in

Maximum
# of Elbows

Reduce the maximum
vent length
accordingly for each
elbow used:
Each 90° elbow
equates to 8 linear
ft (2.4 m) of vent
Each 45° elbow
equates to 4 linear
ft (1.2 m) of vent

Reduce the maximum
vent length
accordingly for each
elbow used:
Each 90° elbow
equates to 5 linear
ft (1.5 m) of vent
Each 45° elbow
equates to 3 linear
ft (0.9 m) of vent

* Approved polypropylene systems include:
Duravent Polypro (Single Wall): 2PPS-xxx (2 in), 3PPS-xxx (3 in)
Centrotherm Innoflue SW: ISxx02xx (2 in), ISxx03xx (3 in)
Refer to manufacturer’s literature for detailed information.
**For installation in Canada, field-supplied plastic vent piping must comply
with CAN/CGA B149.1 (latest edition) and be certified to the Standard
For Type BH Gas Venting Systems, ULC-S636. Components of this listed
system must not be interchanged with other vent systems or unlisted
pipes or fittings. All plastic components and specified primers and glues
of the certified vent system must be from a single system manufacturer
and must not be intermixed with another system manufacturer’s parts.
The supplied vent connector and vent termination are certified as part of
the water heater.

CAUTION

This water heater has a built-in control to limit the exhaust
temperature to 149 °F (65 °C). As a result, the Navien water
heater can be vented with Schedule 40 PVC. If the incoming
(or recirculation return) water temperature does not exceed
150 °F (66 °C), the exhaust temperature will not exceed
149 °F (65 °C).

However, if you set the water heater at a temperature
above 150 °F (66 °C) and you are also incorporating either
an external recirculation loop or a combination heating
system, the exhaust temperature can exceed 149 °F (65 °C).
In that case, you must use Schedule 40 or 80 CPVC or
Approved Polypropylene in the USA or Type BH Special
Gas Vent Class IIB (CPVC) or Class IC (Polypropylene) that
conforms to ULC-S636 in Canada.

In systems with 2 in vents, if the exhaust temperature
exceeds 149 °F (65 °C), CPVC pipe (field supplied) must
be used for the first 3 ft of equivalent pipe length. For
systems with 3 in vents, if the exhaust temperature exceeds
149 °F (65 °C), CPVC pipe (field supplied) must be used for
the first 5 in of equivalent pipe length.

Installing the Water Heater

150 ft
(45 m)

3 in

Note

Equivalent Lengths

The Maximum Length does not include any elbows.

If using a concentric termination as shown on
pages 33-34, count this as 5 linear ft (1.5 m) of
vent.

The maximum vent lengths at high altitudes are
the same as shown in the table above.

3.6.4 Terminating the Vent

Non-concentric Sidewall Venting – Air is drawn from a different
location at a minimum of 12 in (300 mm) from the exhaust
termination. Try to minimize the length of the intake air pipe
with this venting.

Concentric Sidewall Venting

Before installing the water heater, determine what type of vent
termination is appropriate for the installation location and
situation. The subsections that follow describe some typical
venting configurations, but do not include all possible options.
Along with 2 in and 3 in PVC Concentric Terminations shown on
pages 33-34, the following terminations can also be used:

IPEX Low Profile Termination Kits:
2 in Low Profile Vent Kit #196984
3 in Low Profile Vent Kit #196985

Duravent PolyPro Horizontal Concentric Termination Kit
2 in x 4 in Concentric Vent Kit #2PPS-HK
3 in x 5 in Concentric Vent Kit #3PPS-HK

12 in (300 mm) min.

Refer to the vent manufacturer's instructions for detailed
installation procedures.
Indoor Water Heater Installation Venting Examples
The following are some possible indoor venting options:
2 in or 3 in Two-pipe Sidewall Venting
Intake Air
Exhaust Gas

Combustion Air
Combustion Air
Vent

Vent
Maintain 12 in
1 in (25 mm) min. (300 mm) min.*
* Clearance above
highest anticipated
snow level or grade.

Interior View

Do not vertically
stack terminations on
sidewalls.
12 in (300 mm) min.

12 in (300 mm) min.

CAUTION
Refer to the figures below for the orientation of vent if the
IPEX low profile vent kit is used for the termination.

Exhaust Gas
Intake Air

Exterior View
Installing the Water Heater

2 in or 3 in Two-pipe Vertical Venting – Intake and exhaust pipes
do not have to terminate in the same area.
36 in (900 mm) min.
12 in (300 mm) min.

Exhaust Gas

12 in (300 mm) min.

Intake Air

Outdoor Installation
Outdoor installation should only be considered in mild climates.
Freezing temperatures or contaminated air can damage the
water heater. When installing the water heater outdoors, maintain
clearances from building openings, as described in the “Non-Direct
Venting (Single Pipe)“ section on page 30. Outdoor installation
areas should be in an open, unroofed area and should allow for the
following minimum clearances from the water heater:

12 in (300 mm) min.
From any
obstruction (above,
below, left, or right)

Top
Exhaust Gas
Intake Air

Back

Side

Front

Bottom

Concentric Roof Venting
Vent
Combustion Air
Maintain 12 in (300 mm) min.
(18 in (450 mm) min. for Canada)
Clearance above highest
anticipated snow level. Maximum
of 24 in (600 mm) above roof
Combustion Air

Bottom

12 in

Back

0.5 in

Sides

3 in

Front

24 in

Top

36 in

Vent

When installing a water heater outdoors, follow these guidelines:

Installing the Water Heater

The Navien Outdoor Vent Kit must be used to ensure proper
operation of the water heater.
Ensure that there is plenty of clearance around the air intake and
that it is adequately protected to prevent any debris, liquids, or
flammable gases from entering the air intake.
If the water heater is installed under an eave, maintain a
clearance of 3 ft or more from the eave to the top of the water
heater vent terminals.

3.7 Connecting the Power Supply
WARNING
Improperly connecting the power supply can result in electrical
shock and electrocution. Follow all applicable electrical codes
of the local authority having jurisdiction. In the absence of
such requirements, follow the latest edition of the National
Electrical Code (NFPA 70) in the USA or the latest edition
of CSA C22.1 Canadian Electrical Code Part 1 in Canada.
Connecting the power supply should be performed only by a
licensed professional.

When connecting the power supply, follow these guidelines:

Do not connect the electric supply until all plumbing and gas
piping is complete and the water heater has been filled with
water.
Do not connect the water heater to a 220-240 V AC power
supply. Doing so will damage the water heater and void the
warranty.
All water heaters come with a factory-installed, 3-pronged
(grounded) plug. The water heater can be plugged into any
grounded electrical outlet nearby, as it requires only 2-4 Amps.
It is not necessary to run a dedicated electrical line to the water
heater.
If local codes require the water heater to be wired directly,
remove and discard the factory-installed plug. Install a power
switch between the breaker and the water heater to facilitate
end-user maintenance and servicing. Connect the water heater
to a 110-120 V AC at 60 Hz with a maximum of 2 A (4 A if an
external pump is connected) rating electrical supply.
The water heater must be electrically grounded. If using the
power plug, ensure that the electrical outlet you connect the
water heater to is properly grounded. If wiring the water heater
directly to a power supply, do not attach the ground wire to
either the gas or the water piping as plastic pipe or dielectric
unions may prevent proper grounding.
We recommend using a surge protector to protect the water
heater from power surges.
If there is a power failure in cold weather areas, the freeze
prevention system in the water heater will not operate and may
result in freezing of the heat exchanger. In cold weather areas
where power failures are common, you must completely drain
the water heater to prevent damage if the power will be off
for any extended period of time. A battery back-up (available
at most computer retailers) may be used to supply hot water
during periods of power outages. Damage caused by freezing is
not covered under warranty.

3.8 Setting the DIP Switches
The water heater has two DIP switch locations: on the main circuit
board (PCB) and on the front panel. Each location has two sets
of DIP switches that control the functionality of the water heater.
Set the DIP switches appropriately, based on the installation
environment.

3.8.1 Circuit Board DIP Switches
The two sets of DIP switches on the circuit board configure the
water heater’s model settings. These configurations are set at the
factory and should not be changed.

3.8.2 Setting the Front Panel DIP Switches
The two sets of DIP switches on the front panel configure the water
heater’s pump & recirculation, display, well pump, storage tank &
solar system, lime alarm, high altitude, Cascade Venting and Gas
Type settings. Some of these configurations are set at the factory
and should not be changed. The following tables describe the
functions of the DIP switches and their settings:

Installing the Water Heater

10-switch Panel:
Switch

Function
Recirculation ModeInternal Navien
Pump ("A" model
only)

Setting

Remark

No Recirculation

1-OFF; 2-OFF; 3-OFF

Internal Recirculation

1-ON; 2-OFF; 3-OFF

External Recirculation

1-OFF; 2-ON; 3-OFF

Intelligent Preheating*

1-ON; 2-ON; 3-OFF

External Pump Only

1-OFF; 2-OFF; 3-ON

Internal Recirculation ("A" model only)

1-ON; 2-OFF; 3-ON

External Recirculation ("A" model only)

1-OFF; 2-ON; 3-ON

Intelligent Preheating*

1-ON; 2-ON; 3-ON

Celsius

4-ON

Fahrenheit

4-OFF

Well Pump Operation

5-ON

Do Not Use Well Pump

5-OFF

Storage Tank/Solar System Operation

6-ON

Do Not Use Storage Tank/Solar System

6-OFF

6 Months Alert

7-ON; 8-OFF

12 Months Alert

7-OFF; 8-ON

24 Months Alert

7-ON; 8-ON

0–1,999 ft (0–609 m)

9-OFF, 10-OFF

2,000–5,399 ft (610–1,645 m)

9-ON, 10-OFF

5,400–7,699 ft (1,646–2,346 m)

9-OFF, 10-ON

7,700–10,100 ft (2,347–3,078 m)

9-ON, 10-ON

1-3
Recirculation ModeExternal Pump
Connected**

7&8

9 & 10

Note

Display Temperature
Unit
Well Pump
DHW Storage Tank/
Solar System

Lime Alarm***

High Altitude ****

*Intelligent Preheating:
Learns the user's hot water
usage patterns and starts
preheating prior to an
anticipated draw.
Preheating starts when
remote controller is not
connected.
When remote controller is
connected, preheating starts
and operates based on the
timer.
Set the timer on the remote
controller to use hot water
at the time of your choice.
Intelligent preheating does
not function in Cascade
Mode (Preheating OFF).
Freeze protection is still
available with preheating
OFF.
**External Pump:
These settings are to be used
when an external pump is
wired to the water heater.
***Lime Alarm:
Displays a "760" error when
the set time period has been
reached to indicate a flush or
service is necessary.
****High Altitude
Above 2,000 ft (610 m), the
water heater will de-rate by
4% for each 1,000 ft (305 m) of
altitude gain.

This water heater may be installed at elevations up to 10,100 ft (3,078 m) for use with Natural Gas and 4,500 ft (1,370 m) for use
with Propane. To use the water heater at a specific altitude, the DIP switches should be set as described above.

CAUTION
Do not configure the system for DHW recirculation when it is configured to run an air handler using the ComfortAir+ add-on controller.
DHW recirculation and Navien ComfortAir+ configurations cannot be used at the same time.

2-switch Panel:
Switch

Function

Cascade Vent

2
36

Setting
Common Vent

1-OFF

Individual Vent

1-ON

Natural Gas

OFF

Propane Gas

Gas Type

Installing the Water Heater

4. Installing a Cascading System
When installing a cascading system, carefully consider the design of the system and the features of the installation location. Follow all local
codes and regulations, as well as all guidelines for installing the water heater. The following sections describe additional considerations that
are specific to installing cascading systems. Read them carefully before designing or installing the system.

4.1 Connecting Water Supplies
Several options are available for plumbing a cascading system of water heaters. The options shown here are only examples. The setup you
choose will vary based on the installation location, local building codes, and other factors. Follow all applicable regulations when installing a
cascading system.
You can connect up to 16 water heaters to meet high-volume hot water demands. Some possible connection options include the following:

Recirculation via Internal Pumps (“A” model only):

Communication
Cable

Union
Ball Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve

Gas Supply Line
DHW Supply Line

Cold Water Supply Line
Recirculation Line

[NPE-180A/ 210A/ 240A]
Note

The recommended minimum recirculation flow rate for each water heater is 2 GPM. Depending on the number of water heaters
and the diameter of the recirculation line, it may not be necessary to connect all water heaters to the recirculation line. If this is
the case, set the unconnected water heaters to internal recirculation mode. The master water heater must always be connected
to the recirculation line and set to external recirculation mode.

Multiple NPE-S Units:

Communication
Cable

Union
Ball Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve

Gas Supply Line
DHW Supply Line

Cold Water Supply Line

[NPE-150S/ 180S/ 210S/ 240S]
Installing a Cascading System

4.1.1 Piping Sizes and Considerations

Note

When plumbing a cascading system, consider the following pipe
diameters and flow rates. Note that flow rates above 6.6 ft/s may
cause pipe erosion. These specifications may vary depending on
installation conditions.

4.2 Connecting the Communication Cables
Up to 16 water heaters can be connected with Navien Ready-Link
communication cables. Select one of the water heaters in the
cascading system as the master water heater, and then connect the
other water heaters to it as slaves. Before making any connections,
ensure that the power is turned off to all water heaters.

Qty

ΔT=54 ºF
Flow rate (GPM)

Water
Velocity (ft/s)

7.19

4.78

20A

14.38

5.61

25A

1 in

21.57

5.54

30A

1 1/4 in

28.77

5.21

40A

1 1/2 in

35.96

6.53

40A

1 1/2 in

43.15

4.49

50A

2 in

50.34

5.24

50A

2 in

57.5

6.00

50A

2 in

64.72

4.39

65A

2 1/2 in

71.92

4.75

65A

2 1/2 in

79.11

5.34

65A

2 1/2 in

86.30

5.84

65A

2 1/2 in

93.49

6.33

65A

2 1/2 in

100.68

6.79

65A

2 1/2 in

107.87

5.11

80A

3 in

115.07

5.44

80A

3 in

4.2.1 Configuring the Communication Settings

122.26

5.81

80A

3 in

129.45

6.14

80A

3 in

After connecting the Ready-Link communication cables, restore
power to the water heater and turn on all water heaters using the
Power button.

136.64

6.46

80A

3 in

143.83

6.83

80A

3 in

151.02

4.06

100A

4 in

158.21

4.25

100A

4 in

165.41

4.45

100A

4 in

172.60

4.65

100A

4 in

179.79

4.85

100A

4 in

186.98

5.05

100A

4 in

194.17

5.24

100A

4 in

201.36

5.44

100A

4 in

208.56

5.61

100A

4 in

215.75

5.81

100A

4 in

Installing a Cascading System

Pipe
Diameter (mm/in)

The table above is based on model NPE-240A.

/4 in

Connect the Ready-Link cables to the J6 ports on the right side of
the front panel:

To configure the communication settings:
1. On the master water heater, press and hold the Diagnostic
and Up(+) buttons for more than 5 seconds. “MA.00” will
appear on the display to confirm that this water heater is set as
the master.

2. On the slave water heater, press and hold the Diagnostic and
Down(-) buttons for more than 2 seconds. “SL.01” will appear
on the display to confirm that this water heater is set as a slave.

3. Repeat step 2 to configure the rest of the slave water heaters in
the system.
4. On the master water heater, press and hold the Diagnostic
and Up(+) buttons for more than 5 seconds. All the display
screens on the configured water heaters will return to the
temperature display.
Note

To add additional slaves at a later time, repeat step
2.

To cancel the cascading communication setup,
on the master water heater, press and hold
the Diagnostic and Reset buttons for more
than 5 seconds. The water heaters will revert
to independent operation. Repeat steps 1-4 to
reassign the master water heater.

Installing a Cascading System

5. Appendixes
5.1 Gas Conversion

Water Heater
This water heater is configured for Natural Gas from the factory. If
conversion to Propane Gas is required, the conversion kit supplied
with the water heater must be used.

WARNING

NPE-240A
NPE-240S

This conversion kit shall be installed by a qualified service
agency* in accordance with Navien’s instructions and all
applicable codes and requirements of the authority having
jurisdiction. The information in these instructions must be
followed to minimize the risk of fire or explosion or to prevent
property damage, personal injury or death. The qualified
service agency is responsible for the proper installation of
this kit. The installation is not proper and complete until the
operation of the converted appliance is checked as specified in
the manufacturer’s instructions supplied with the kit.

1STAGE

2STAGE

1STAGE

2STAGE

Ø6.10

Ø6.30

Ø4.50

Ø4.80

Table 1. Orifice size
Gas Pressure and Conversion Kit Number Labels

Procedure:
1. Turn off both gas and water supply to the water heater.
2. Using a Phillips hand screwdriver, remove 4 screws (2 from the
top and 2 from the bottom) of the front cover assembly to gain
access to the internal components. See Figure 1 for illustration
of the front cover on the unit.

* A qualified service agency is any individual, firm, corporation or company
which either in person or through a representative is engaged in and
is responsible for the connection, utilization, repair or servicing of gas
utilization equipment or accessories; who is experienced in such work,
familiar with all precautions required, and has complied with all of the
requirements of the authority having jurisdiction.

In Canada: The conversion shall be carried out in accordance with
the requirements of the provincial authorities having jurisdiction
and in accordance with the requirements of the CAN‐B149.1 and
CAN1‐B149.2 Installation Code.

Tools Required:

Phillips Screwdriver
Flathead Screwdriver
5
/32 in or 4 mm Allen Wrench
Combustion Analyzer or Dual Port Manometer
Gas Leak Detector

Figure 1. NPE Series Front cover

Included Items:

Gas Orifice (refer to below table)
Water Heater

NPE-150S

Ø6.30

Ø5.10

Gas Inlet
Pipe

Gas Valve

Water Heater
NPE-180A
NPE-180S

1STAGE

2STAGE

1STAGE

2STAGE

Ø4.80

Ø5.95

Ø3.80

Ø4.70
Figure 2. NPE Series Internal Components

NPE-210A
NPE-210S

Appendixes

Ø6.10

Ø6.30

Ø4.50

Ø4.80

3. Once the front cover is removed, place it in a safe location to
prevent accidental damage. With the internal components
exposed, locate the gas inlet pipe and the Gas Valve near the
left side of the unit which are highlighted in Figure 2.
4. Use a Phillips screwdriver to remove the two screws at Location
A - the connection below the Gas Valve where it connects
to the pipe. See Figure 3 for reference. Once the screws are
removed, carefully separate the pipe from the Gas Valve.
5. Once the gas inlet pipe is detached from the Gas Valve, find
Location B - the connection above the Gas Valve where it is
attached to the Fan Motor Assembly. Carefully remove the four
screws by hand using a Phillips screwdriver and pull the Gas
Valve away from the Fan Assembly to access the Gas Orifice.

6. Once the Gas Orifice is exposed, remove the two screws that
hold the part in place. Remove the Gas Orifice from its housing
and prepare the new Gas Orifice for the LP conversion for
installation.

Remove two (2)
screws here

Location B:
Remove four
(4) screws here

Figure 4. Access to Gas Orifice in Fan Assembly

WARNING
Location A:
Remove two (2)
screws here

Figure 3. Detaching Gas Valve from
Gas Inlet Pipe and Fan Motor Assembly

DO NOT adjust or attempt to measure gas valve outlet
pressure. The gas valve is factory-set for the correct outlet
pressure. This setting is suitable for natural gas and propane,
requiring no field adjustment.

Attempting to alter or measure the gas valve outlet pressure
could result in damage to the valve, causing potential severe
personal injury, death or substantial property damage.
Navien water heaters are shipped ready to fire natural gas
ONLY.

Appendixes

Packing

DANGER

Gas Orifice

See Figure 5. Inspect the O-ring between the gas valve and
gas valve inlet adapter whenever they are disassembled.
The O-ring must be in good condition and must be installed.
Failure to comply will cause a gas leak, resulting in severe
personal injury or death.

O-ring

LP
NPE-150S

NPE-180A/ 210A/ 240A/ 180S/ 210S/ 240S

Figure 6. Orifice identification

7. Replace the old Orifice piece with the new part for use with LP
gas. Ensure that the Orifice is properly seated inside the port
before proceeding to the next step.

8. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
Note

Do not overtighten as this may damage or crack
the components.

DANGER

Gas Orifice

Inspect the O-ring between the gas valve and gas valve inlet
adapter whenever they are disassembled. The O-ring must be
in good condition and must be installed. Failure to comply will
cause a gas leak, resulting in severe personal injury or death.

O-ring

9. Set the Front Panel Dip switch according to the gas type.

WARNING
Be sure to turn off the power before changing the DIP switch
setting.

Figure 5. Exploded view of Gas assembly

Appendixes

ON
1

ON
2

High fire

Low fire

%CO2

8.9

9.5

10.2

10.8

NPE-180A
NPE-180S

8.9

9.5

10.2

10.8

NPE-210A
NPE-210S

8.9

9.5

10.2

10.8

NPE-240A
NPE-240S

8.9

9.5

10.2

10.8

Water
Heater
2

Fuel

NPE-150S
NG

LP
1

DANGER

When conversion is required, be sure to set the Front Panel
DIP switches according to the supply gas type.
Failure to properly set the DIP switches could cause carbon
monoxide poisoning, resulting in severe personal injury or
death.

10. Turn on the gas and water supply to the water heater.
11. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer (recommended)
a. Loosen the screw, rotate the plate and remove the gasket
to access the emissions monitoring port as shown in
Figure 7.
b. Insert the analyzer into the port (Figure 7).

Table 2. CO2 and CO value
(CO2 values must be within 0.5% of the values listed.)
c. Fully open several hot water fixtures and set the
water heater to operate at 1-stage MIN mode (refer to
page 45). Measure the CO2 value at low fire.
If the CO2 value is not within 0.5% of the value listed in
Table 2, the gas valve set screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 8. Using a 5/32 in or 4 mm Allen wrench, turn
the set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the CO2 value.

Figure 8. Set Screw Location

Figure 7

Note

The set screw is located behind the screw-on
cover. This must be removed first.

Appendixes

d. Fully open several hot water fixtures and set the water
heater to operate at 2-stage MAX mode (refer to
page 45). Measure the CO2 value at high fire.
If the CO2 values do not match Table 2 at high fire, do not
adjust the gas valve. Check for the proper Gas Orifice.

DANGER

c. Fully open a hot water fixture and set the water heater to
operate at 1-stage MIN mode (refer to page 45). Measure
the offset value at low fire and compare it to the values in
Table 3. If the offset value is out of range, the gas valve set
screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 10. Using a 5/32 in or 4 mm Allen wrench, turn
the set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the offset value.

Improper gas valve settings can cause severe personal injury,
death or substantial property damage.
Option 2. Using Digital Manometer
a. Open the offset pressure port by loosening the screw two
turns as shown in Figure 9.

Figure 10

Note

d. At high fire, do not check the offset value and never adjust
the gas valve.

Figure 9

b. Connect a manometer to the offset pressure port. For dual
port manometers, use the positive pressure side.
Model

The set screw is located behind the screw-on
cover. This must be removed first.

Kit Part No.

Gas Type

Offset

NAC-N6

-0.03 in ± 0.01 in

NAC-L6

-0.04 in ± 0.01 in

NAC-01

-0.03 in ± 0.01 in

NAC-100

-0.04 in ± 0.01 in

NAC-02

-0.02 in ± 0.01 in

NAC-200

-0.04 in ± 0.01 in

NAC-03

-0.02 in ± 0.01 in

NAC-300

-0.04 in ± 0.01 in

DANGER
Improper gas valve settings can cause severe personal injury,
death or substantial property damage.

NPE-150S
NPE-180A
NPE-180S
NPE-210A
NPE-210S
NPE-240A
NPE-240S

Table 3. Offset value for low fire

12. Once the CO2 or offset values have been confirmed, apply the
included conversion stickers to show that the appliance has
been converted to propane gas. Place this labels adjacent to
the rating plate as shown in Figure 11.
This unit has been
converted to Propane fuel
Cet appareil a ete converti au Propane
Orifice Size / Injecteur:
Min. 4.5 mm to Max. 4.8 mm
Inlet Gas Pressure / Pression d'entrée du gaz:
Min. 8.0 to Max. 13.0 inches
Manifold Gas Pressure /
Pression à la tubulure d’alimentation:
Min. -0.02 to Max. -0.66 inches WC
BTU Input / Debit calorifique:
Max. 180,000 - Min. 19,900 BTUh
Conversion Kit No.: NAC-02

This water heater was converted on
______/______/______ to ____________ gas
with Kit No. ________________________
by _________________________________
_________________________________
(name and address of organization making
this conversion, who accepts responsibility
for the correctness of this conversion)

Figure 11. Proper Placement of Gas Conversion Labels

Appendixes

5.1.1 Setting the Operation Mode
1. Using the Front Panel, press and hold the Diagnostics Button
for over 5 seconds until “1.TST” is displayed.
2. Press the + (Up) button once to change the display to “2.OPR”.
3. Press the Information Button once to acess the Operation
Mode menu.
4. Press the + (Up) button once to set the water heater to
opearate at 1-stage MIN (“MIN.1”).
5. To set the water heater to operate at 2-stage MAX (1-stage
MAX for NPE-150S), press the + (Up) button 3 times or until
“MAX.2 (MAX.1 for NPE-150S)” is displayed.
6. To exit the Operation Mode and return the water heater to
normal operation, press the Reset button twice.

Diagnostics
Information
Reset

Appendixes

5.2 Technical Data
Pressure Drop Curve

2TGUUWTG.QUU RUK

9CVGT(NQY )2/

[NPE-240A/ 240S]

2TGUUWTG.QUU RUK

9CVGT(NQY )2/

[NPE-210A/ 210S]

2TGUUWTG.QUU RUK

9CVGT(NQY )2/

[NPE-180A/ 180S]

2TGUUWTG.QUU RUK

9CVGT(NQY )2/

[NPE-150S]
46

Appendixes

Outlet Flow Data

(NQY )2/

ů66GORGTCVWTG4KUG ș

[NPE-240A]

(NQY )2/

ů66GORGTCVWTG4KUG ș

[NPE-210A]

(NQY )2/

ů66GORGTCVWTG4KUG ș

[NPE-180A]
Note

At altitudes above 2,000 ft (610 m), the outlet flow will be reduced by 4% for each 1,000 ft (305 m) of altitude gain.

Appendixes

(NQY )2/

Outlet Flow Data

ů66GORGTCVWTG4KUG ș

(NQY )2/

[NPE-240S]

ů66GORGTCVWTG4KUG ș

(NQY )2/

[NPE-210S]

ů66GORGTCVWTG4KUG ș

[NPE-180S]

(NQY )2/

ů66GORGTCVWTG4KUG ș

[NPE-150S]
Note

Appendixes

At altitudes above 2,000 ft (610 m), the outlet flow will be reduced by 4% for each 1,000 ft (305 m) of altitude gain.

Color Code

Water Adjustment Valve
Feedback

replaced, they must be replaced
with their equivalent.

supplied with the water heater must be

B
B

R
W
BK
R
W
BK

If any of the original wires as

Ground

WAV

Exhaust Thermistor

Outlet1 Thermistor

Inlet2 Thermistor

Outlet2 Thermistor

B
B

Flow Sensor

Air Pressure Sensor

High Limit S/W

: Blue
: Orange
: Red
: White
: Yellow
: Black
: Brown
: Green/Yellow

Inlet1 Thermistor

APS

B
O
R
W
Y
BK
BR
GY

BR
O
R
B
Y
R
W
BK

CON7

CON6

CON10
F

CON8

CON5

L
CON4

BK BK BK BKBK BKBK BKBK BKBK BK

Front Panel

TB1

CON3

CON2

CON11

CON1

Power Switch

Fuse(5A)
GY

Dual Venturi

Spark
Electrode

Flame Rod

Main Gas Valve

MGV

Fan Motor

Y
R OW BK

Pump

Hot(BK)

External
Pump

Ground

Optional

W
Y
R

BR
B

BK
B
BR

Neutral(W)

Power Cord
Ground(GY)

5.3 Wiring Diagram

[NPE-180A/ 210A/ 240A]

Appendixes

[NPE-150S/ 180S/ 210S/ 240S]

Appendixes

Color Code

High Limit S/W

: Blue
: Orange
: Red
: White
: Yellow
: Black
: Brown
: Green/Yellow

Mixing Valve
Feedback

Water Adjustment Valve
Feedback

be replaced, they must be replaced
with their equivalent.

supplied with the water heater must

BR
O
R
B
Y
R
W
BK

B
BR
O
R
B
Y
R
W
BK

B
B

R
W
BK
R
W
BK

B
B

If any of the original wires as

Ground

MIX

WAV

Exhaust Thermistor

Outlet1 Thermistor

Inlet2 Thermistor

Outlet2 Thermistor

Inlet1 Thermistor

Flow Sensor

APS Air Pressure Sensor

B
O
R
W
Y
BK
BR
GY
BK BKBK

CON10

CON9

CON7

CON6

Front Panel

CON8

CON5

L
CON4

BKBK BKBK BKBK BKBK BK

TB1

Anti-Frost Heater

CON3

CON2

CON11

CON1

Power Switch

Fuse (5A)

Freeze Protect S/W

BR
B

BK
B
BR

Dual Venturi

Spark
Electrode

Flame Rod

W
Y
R

Main Gas Valve

MGV

Fan Motor

Y
R OW BK

Hot(BK)

External
Pump

Ground

Optional

Neutral(W)

* NPE-180S/ 210S/ 240S only

W
BK

Power Cord
Ground (GY)

5.4 Ladder Diagram
NEUTRAL

3.15A

HOT

EXT_PUMP

Relay 1

EMI
FILTER

VENTURI

Relay 2

Relay 3

IGNITER

Relay 4

PUMP

PWM

FAN
Primary

Primary
SMPS
DC15V

Secondary

Speed Control

DC24V

DC12V
Water Adjust
Valve

DC5V

FSA Power
Switch

200V

Flow Control

Flame Rod

Flow Sensor

APS
H.T.L
Fan
Hall Sensor

WD-PSS

Outlet
Thermistor 1

Driving Circuit
Relay 3

Outlet
Thermistor 2

MCU 1

MGV1

MCU 2

MGV2
Inlet
Thermistor 1

Relay 1
Relay 2

Inlet
Thermistor 2
Exhaust
Thermistor

Relay 4

Communication
Interface
UART
Communication
Interface

Ready Link
Interface

FRONT
PANEL

Ready Link

[NPE-180A/ 210A/ 240A]

Appendixes

NEUTRAL

3.15A

HOT

EXT_PUMP

Relay 1

EMI
FILTER

* NPE-180S/ 210S/ 240S only
Relay 2

VENTURI

Relay 3

IGNITER

Relay 4

PUMP

PWM

FAN
Primary

Primary
SMPS
Speed Control

DC15V

Secondary

DC24V

DC12V
FSA Power
Switch

DC5V
Water Mixing
Valve

Flame Rod

Flow
Control

Water Adjust
Valve

200V

Flow Sensor

APS
H.T.L
Fan
Hall Sensor

WD-PSS

Outlet
Thermistor 1

Driving Circuit
Relay 3

Outlet
Thermistor 2

MCU 1

MGV1

MCU 2

MGV2
Inlet
Thermistor 1

Relay 1
Relay 2

Inlet
Thermistor 2
Exhaust
Thermistor

Relay 4

Communication
Interface
UART
Communication
Interface

Ready Link
Interface

[NPE-150S/ 180S/ 210S/ 240S]

Appendixes

FRONT
PANEL

Ready Link

5.5 Component Assembly Diagrams and Parts Lists
5.5.1 Case Assembly

12
1
11

2
4
3
6

17
16
15
14
5
18
13

Appendixes

Description

Part #

Intake Air Duct Assembly

30008662B

Intake Air Filter

20007667A

Case

Remark

20019078C

NPE-180A/210A/240A

20026559B

NPE-150S/180S/210S/240S

Air Pressure Sensor

30010346A

Panel Bracket

20018388A

Cover

30008678B

NPE-180A/210A/240A

30011694A

NPE-150S/180S/210S/240S

Case Lower Bracket

20007643B

PCB

30011969A

Power Switch

30009482A

Front Panel

30008333A

Case Bracket

20007609A

Exhaust Pipe Assembly

30008673A

Rubber Ring

20025127A

Saddle

20013508A

NPE-150S/180S/210S/240S

Saddle Bracket 1

20026170A

NPE-150S/180S/210S/240S

Freeze Protector Sensor

30002587A

NPE-150S/180S/210S/240S

Freeze Protector Sensor Bracket

20007671A

NPE-150S/180S/210S/240S

Saddle Bracket 2

20026172A

NPE-150S/180S/210S/240S

Appendixes

5.5.2 Burner Assembly(NPE-180A/ 210A/ 240A)
6

18
13
3
5

7-1

8
6-1

12
6-1

15
12

6-1

4-1

17-1

4
17

11-1
6-1

12
17
6-1

12
6

Appendixes

Description

Heat Exchanger Assembly

Remark

20018362A

NPE-180A

30008780A

NPE-210A/240A

Fan Packing

20022744A

Fan Bracket (F)

20022095A

Flow Sensor Assembly

30008571A

Thermistor

30008366A

Fan Braket (R)

20022096A

Cold Inlet Pipe

4-1

6-1

30009166A

NPE-180A

30008446A

NPE-210A/240A

O-Ring (Φ17.5 x 2.7 t)

20006947A

WPA-A (Clip)

20018344A

Thermistor

30008366A

WPA-B

20018343A

H-Ex Middle Pipe

7
7-1

10
11

30009126A

NPE-180A

30008439A

NPE-210A/240A

30009145A

NPE-180A

30008442A

NPE-210A/240A

Hot Water Outlet Pipe
WPA-A (Screw)

30008569A

Thermistor

30008366A

Fastner

20017726A

Ignition Transformer

30010455A

Fastner

20007853A

Ignitor

30008591A

Damper

30008825A

Buffer Tank Inlet Adapter

20018346A

O-Ring (P16)

30009478A

Thermistor

30009478A

11-1

17-1
18

Part #

Appendixes

5.5.3 Burner Assembly(NPE-150S/ 180S/ 210S/ 240S)

2
18

3
10

15
14

20
10
4

10
17
21

10
5

10 6
22
19

9
24

10 15

9
10

6
10
8
9
10
11

Appendixes

Description

Part #

Ignition Transformer

30010455A

Fan Bracket (R )

20022096A

Thermistor

30009478A

Exhaust

30214351A

NPE-150S

30011706A

NPE-180S

30011705A

NPE-210S

30011704A

NPE-240S

30214183A

NPE-150S

30012226A

NPE-180S/210S/240S

Ignitor

Packing (Φ26.5 x 2.4 t)

20006868A
30014326A

NPE-150S

30011519A

NPE-180S

30011515A

NPE-210S/240S

Heat Exchanger Outlet Pipe

WPA-C (Screw)

20026780A

Fastner

20017726A

O-Ring (Φ17.5 x 2.7 t)

Cold Inlet Pipe

20006947A
30214751A

NPE-150S

30011521A

NPE-180S

30011665A

NPE-210S

30011517A

NPE-240S

Fan Damper

30008825A

Fan Packing

20022744A

Fan Bracket (F)

20022095A

Backup Ring

20018744B

High Limit Switch

30002577A

Fastner

20007853A

WPA-A (Clip)

20018344A

Thermistor

30008366A

Water

20033191A

NPE-150S

20018343A

NPE-180S/210S/240S

30014330A

NPE-150S

30009126A

NPE-180S/180A

30010803A

NPE-210S/210A

30008439A

NPE-240S/240A

WPA-B

H-Ex Middle Pipe

WPA-A (Screw)

Heat Exchanger Assembly

Remark

Mixing Pipe

WPA-T

Hot Water Outlet Pipe

Appendixes

30008569A
30014327A

NPE-150S

30011518A

NPE-180S

30011514A

NPE-210S/240S

20025960A
30014328A

NPE-150S

30011520A

NPE-180S

30011516A

NPE-210S/240S

5.5.4 Waterway Assembly(NPE-180A/ 210A/ 240A)
8-3

8-4

15
8

8-2

1
8-1

11
3-5

2-4

3-3

2-4

9-3
9-2

3-2

3-4

3-1

7-1

4-1

4-3

2-3

2-2

11
4

2-1

9-1

2-5

9-3

12-5

4-2

12-4
12-2

12-3

12-1

Description

Part #

Buffer Tank

30010953A

Hot Water Outlet Pipe Assembly

30008338A

2-1

Pipe Adapter

30008349A

2-2

O-RING (P20)

20017212A

2-3

Thermistor (Red)

30008366A

2-4

O-RING (P16)

20006947A

2-5

Pipe Clip

20007733A

Return Pipe Assembly

30008350A

Pipe adapter

30008349A

3
3-1

Remark

Appendixes

Description

Part #

3-2

O-RING (P20)

20017212A

3-3

O-RING (P19)

20017211A

3-4

Water Filter

30008351A

3-5

Pipe Clip

20007733A

Circulation Pump

30010346A

4-1

Pump Air Seperator

30006831A

4-2

Drain Plug

30003550B

4-3

O-RING (P18)

20006947A

Fastner

20017726A

Water adjustment valve (WAV)

30008245A

WAV Outlet Pipe Assembly

30008624A

O-Ring (P16)

20011438A

Syphon

30009756A

8-1

O-Ring (Φ31.7x3.5t)

20018013A

8-2

Syphon Clip

20018155A

8-3

Hose Clip

20007833A

8-4

Syphon Hose

20018429A

Pump Outlet Pipe Assembly

30008361A

9-1

Check Valve

30008360A

9-2

Pipe Clip

20017722A

9-3

O-Ring (P16)

20017210A

Return Pipe clip

20017767A

Fastner

20007859A

Cold Water Inlet Pipe Assembly

30009437A

12-1

Water Filter

30008351A

12-2

O-RING (P19)

20017211A

12-3

Pipe adapter

30008349A

12-4

O-RING (P20)

20017212A

12-5

Pipe Clip

20007733A

O-RING (P29)

20017923A

Buffer Tank adapter

20017757A

Buffer tank pipe A

20017759A

Buffer tank pipe B

20017760A

Fastner

20017724A

7-1
8

Appendixes

Remark

5.5.5 Waterway Assembly(NPE-180S/ 210S/ 240S)
11

8
6
8
12

15
14

6
17

13
16

3
2

Appendixes

Description

Part #

Bracket

20026489A

Thermistor

30008366A

Water Filter

30008171A

Cold Water Inlet Adapter

30011597A

O-Ring (P15)

20017217A

Fastner

20007859A

Flow Sensor

30011534A

O-Ring (P16)

20017210A

Flow Sensor Outlet Adapter

20025959A

Outlet Adapter

20025961A

Fastner

20017726A

Water Adjustment Valve (WAV)

30011532A

Inlet Adapter

20025962A

O-Ring (P18)

20006947A

How Water Outlet Adapter

30011601A

Siphon

30009756B

Siphon Hose

20018429A

Appendixes

Remark

5.5.6 Fan(Gas) Assembly

6
9

15
9
1
9

10
9
12
11
9

2
9

7
9
3
9

14
9
13
9

10
9

4
9
10
9

8
9
5
9

[NPE-180S/ 180A/ 210S/ 210A/ 240S/ 240A]

12
11

10
2

10
13
16
4
10
8

[NPE-150S]
Appendixes

Description

Gas Adapter

Gas Pipe

Remark

30009921A

NPE-180S/180A

30009922A

NPE-210S/210A/240S/240A

30014329A

NPE-150S

30013323A

NPE180S/180A

30008431A

NPE-210S/210A/240S/240A

Gas Connector

20018430A

Gas Valve

30008429A

Gas Inlet Adapter

20023809A

Fan Assembly
Single Venturi

Dual Venturi

Silence

30015421A

NPE-150S

30008834A

NPE-180S/180A/210S/210A/240S/240A

30014688A

NPE-150S

30009219A

NPE-180S/180A

30008909A

NPE-210S/210A/240S/240A

30015322A

NPE-150S

20019142A

NPE-180S/180A

20023829A

NPE-210S/210A/240S/240A

20023861A

NPE-180S/180A

20019141A

NPE-210S/210A/240S/240A

Silence Adapter

O-Ring (P20)

20006934A

O-Ring (G70)

20007001A

NPE-150S

O-Ring (G75)

20018079A

NPE-180S/180A/210S/210A/240S/240A

Fan Packing

20022744A

11
12

Part #

Gas Orifice

20029420B

NPE-150S (NG)

20034178A

NPE-150S (LP)

20024159A

NPE-180S/180A (NG)

20024190A

NPE-180S/180A (LP)

20019144A

NPE-210S/210A/240S/240A (NG)

20024189A

NPE-210S/210A/240S/240A (LP)

20030893A

NPE-150S

Venturi Packing

20022660A

NPE-180S/180A/210S/210A/240S/240A

O-Ring (P34)

20019090A

NPE-180S/180A/210S/210A/240S/240A

Silence Packing

20032129A

NPE-150S

Appendixes

5.6 Installation Check list
After installing the water heater, review the following checklist. You should be able to answer “Yes” to all of the items in the checklist. If not,
review the appropriate sections to complete the installation. To troubleshoot any operational problems refer to “Troubleshooting” in the
Owner’s Manual.
If you have additional questions or need assistance with installation, contact Technical Support at 1-800-519-8794 or 1-949-420-0420, or refer
to the technical support section of Navien’s website (www.navien.com).
Installing the Water Heater

Yes

Have you maintained the required clearances from building openings and intake air vents?
Have you minimized the distance between the water heater and the vent termination?
Have you minimized the distance between the water heater and major fixtures?
Have you maintained the proper service and maintenance clearances?
Is the make-up air supply sufficient for proper operation?
Is the make-up air supply free from dust, dirt, corrosive elements, and flammable vapors?
Is the water heater and vent piping clear of combustible materials, including clothing, cleaning materials, and rags?

Connecting the Gas Supply
Does the gas supply match the type specified on the water heater’s rating plate?
Is the gas line at least 1/2 in or 3/4 in ID (Inner Diameter)?
Is the gas supply line sufficient in length and diameter to deliver the required BTUs?
Have you measured the pressure of the gas supply line?
Is the gas supply pressure within the recommended ranges specified in this manual?
Is the gas supply line equipped with a manual full port valve?
Have you tested the gas line pressure and all fittings for leaks?
Has the gas company inspected the installation, if required?

Connecting the Water Supply
Is the water supply pressure sufficient (greater than 40 PSI)?
Have you installed shut off valves on the inlet and outlet to facilitate cleaning of the inlet water filter?
Have you bled the air out at each fixture?
Have you checked each fixture to ensure hot water is being supplied?
Have you cleaned the inlet water filter?
If you installed a recirculation line, have you insulated the hot water pipes and the return line?

Connecting a Pressure Relief Valve
Have you installed an approved pressure relief valve on the water heater?
Does the rating of the pressure relief valve match or exceed the maximum BTU rating of the water heater?
Is the pressure relief valve at least 3/4 in in diameter?

Appendixes

Connecting a Pressure Relief Valve

Yes

Have you installed the pressure relief valve on the hot water outlet pipe near the water heater?
Have you installed a discharge drain tube from the pressure relief valve to within 6–12 in (150–300 mm) of the floor?

Connecting the Condensate Drain
Have you installed a condensate drain line from the water heater to a drain or laundry tub?

Venting the Water Heater
Have you vented the water heater with 2 in or 3 in PVC, CPVC, Polypropylene, Type BH Special Gas Vent (ULC-S636) for
Category IV Water Heaters (Canada), or in accordance with all local codes and the guidelines in this manual?
Have you ensured that PVC cellular core pipe has not been used as venting for the water heater?
Is the vent sloped upward toward the vent termination at a rate of 1/4 in per foot (2 % grade)?
Are all vent runs properly supported?
Have you properly supported the vent termination?
Have you properly sealed all air intake and exhaust joints, from the flue collar to the to the vent termination?
Have you installed end caps on the exhaust and intake pipes?
Have you checked the venting for leaks?
Is the vent termination at least 12 in (300 mm) above the exterior grade?
Have you ensured that sufficient make-up air is available?
Is the total vent length within the maximum vent length restriction?

Connecting the Power Supply
Is the supplied voltage 110-120 VAC?
Is the water heater plugged into a properly grounded outlet?
If you have made a direct power supply connection, have you installed a power switch to facilitate end-user
maintenance?
Have you checked the polarity of the electrical connection?
Is the system properly set up for cascading operation (master and slave water heaters), if applicable?

Setting the DIP Switches
Have you verified the positions of all DIP switches on the circuit board?
Have you verified the positions of all DIP switches on the front panel?

Operating the Water Heater
Have you shown the owner how to clean the inlet water filter?
Have you given the Installation Manual and Owner’s Manual to the owner for future reference?
Have you shown the owner how to shut off the gas in case of an emergency?

Appendixes

5.7 Navien ComfortAir+ Add-on Controller Kit (Optional)
The Navien ComfortAir+ is an add-on controller for the Navien NPE-A series water heaters. It adds input and
output functions to the NPE-A series water heaters for a combination application where space heating and
domestic hot water (DHW) are supplied simultaneously. With this add-on controller, a thermostat (1 or 2-stage)
and an outdoor sensor can be installed along with a hydronic air handler to add space heating functionality to
the system.

CAUTION
This device is designed to work with the NPE-A series models ONLY.

Basic Principles
The following diagram shows the basic operation of an NPE-A series water heater system with the Navien ComfortAir+ add-on controller.

NPE-A Series
Water Heater

Outdoor Sensor

Thermostat
Heat Demand
Output
Expansion
Tank

Space Heating
Supply

Check
Valve

Space Heating
Return

Flow Switch

Cold Water
Supply

Mixing Valve

DHW Supply

For details, refer to the installation manual that is provided with the ComfortAir+ add-on controller kit.

Appendixes

5.8 Navien On-Demand Control Kit (Optional)
Navien On Demand Control Kit is an add-on input board for the Navien NPE-A series water heaters. It adds
signal input functions to the NPE-A series water heaters for more efficient DHW hot water recirculation
functionality.
With the On Demand Control Kit, DHW recirculation is carried out exactly when the actual demands arise.
This prevents energy loss caused by unnecessary operation of the burner a nd pump throughout th e day.
The On Demand Control Kit can receive signals from multiple push buttons installed in various areas and
performs optimal DHW recirculation only when there is a demand for hot water.

CAUTION
This device is designed to work with the NPE-A series models ONLY.

Basic Principles
The following diagram shows the basic operation of an NPE-A series water heater system with the Navien On-Demand control kit.

CAUTION

SW1
R7

CON2 D1

CE1

SIGNAL 1

SIGNAL

CON1

12 V

C7
C1
C2

GND

SIGNAL 2

SIGNAL

CON3

SIGNAL 3

C4
ZD1

GND

The Navien On-Demand control kit can be used ONLY with a water heater system configured for DHW recirculation.

RA1
U1

CE1
1

SW1

Push button
contact signal

To cold water inlet

DHW return
(to recirculation inlet)

DHW supply
(to hot water fixtures)

City water supply

Cold water line

For details, refer to the installation manual that is provided with the On-Demand control kit.

Appendixes

Push button
contact signal

5.9 Requirements for the State of Massachusetts
NOTICE BEFORE INSTALLATION
This appliance must be installed by a licensed plumber or gas fitter in accordance with the Massachusetts Plumbing and Fuel Gas Code 248
CMR Sections 2.00 and 5.00.
IMPORTANT: In the State of Massachusetts (248 CMR 4.00 & 5.00)
For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for
residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than
seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall
be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At the time of installation of the side wall horizontal vented gas fueled equipment,
the installing plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back‐up is
installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter shall observe that a
battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or
structure served by the side wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner to secure the
services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard wired carbon
monoxide detector with alarm and battery back‐up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner shall have a
period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery
operated carbon monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector as required in accordance with the above provisions shall
comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of
eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than one‐half (1/2) inch in size, "GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL
OBSTRUCTIONS".
4. INSPECTION. The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation
unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of
248 CMR 5.08(2)(a)1 through 4.

Appendixes

Memo

Installation Manual
NPE Condensing Water Heaters
Getting Service
If your water heater requires service, you have several options for getting service:
Contact Technical Support at 1-800-519-8794 or on the website: www.navien.com.
For warranty service, always contact Technical Support first.
Contact the technician or professional who installed your water heater.
Contact a licensed professional for the affected system (for example, a plumber or electrician).
When you contact Technical Support, please have the following information at hand:
Model number
Serial number
Date purchased
Installation location and type
Error code, if any appears on the front panel display
Version: 5.0 (Jul 30, 2015)

Navien, Inc.
800.519.8794 www.Navien.com
20 Goodyear, Irvine, CA 92618

T H E

L E A D E R

I N

C O N D E N S I N G

T E C H N O L O G Y

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