REU 2532 W Service Manual 08 03.pmd Rinnai

2013-04-23

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Continuum and Integrity
REU2532-W and REU2532-WC
Series Water Heaters
SERVICE MANUAL

Rinnai Corporation
103 International Drive
Peachtree City, Ga. 30269
Telephone number (800)621-9419
No portion or part of this manual may be copied without prior permission from Rinnai Corporation.

Key to Warning Symbols

Failure to comply with the following instructions may results in serious personal injury or
damage to the appliance.

Be careful of possible electric shock. Wiring inside this appliance may potentially be at 120
volts.

Disconnect power supply to unit when carrying out the following service repairs.

Read Fault Diagnosis and Wiring Diagram carefully to avoid incorrect wiring.

Do not disassemble. Parts within can not be exchanged or diagnosed faulty.

Please follow instructions in chapters to ensure safe and appropriate service.
After completing the service and confirming that there are no water or gas leaks or incorrect wiring,
test operation of the appliance. After confirming normal operation, explain what was serviced to the
customer and the operating principles, if necessary.
The information in this manual was compiled by Rinnai Technical Services. While many individuals
have contributed to this publication, it will be successful only if you – the reader and customer – find
it useful. We would like to extend an invitation to users of this manual to make contact with us, as
your feedback and suggestions are valuable resources for us to include as improvements. Rinnai is
constantly working toward supplying improved appliances as well as information, and specifications
may be subject to alteration at any time.

REU-2532W Series

Rinnai

Table of Contents

Glossary of Terms and Symbols .............................................................................................................. 4
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.

Introduction .................................................................................................................................. 5
Features ......................................................................................................................................... 6
Dimensions .................................................................................................................................... 8
Installation .................................................................................................................................... 9
Remote Controls ......................................................................................................................... 10
Safety Devices ............................................................................................................................. 12
Specification ................................................................................................................................ 14
Cut-away Diagram ............................................................................................................... ..... 16
Schematic Diagram .................................................................................................................... 17
Combustion Specifications ........................................................................................................ 18
Dip Switch Positions ................................................................................................................... 19
Water Flows ................................................................................................................................ 22
Main Components ...................................................................................................................... 24
Time Charts ................................................................................................................................ 26
Operation Flow Principle .......................................................................................................... 28
Operation Principles .................................................................................................................. 30
Error Messages ........................................................................................................................... 32
Diagnostic Points ........................................................................................................................ 34
Wiring Diagram ......................................................................................................................... 35
Fault Diagnosis ........................................................................................................................... 36
Electrical Component Analysis ................................................................................................. 37
Gas Conversion........................................................................................................................... 47
Gas Pressure Setting Procedure ................................................................................................ 52
Dismantling for Service ............................................................................................................. 54
Exploded Diagram ..................................................................................................................... 60
Parts List ..................................................................................................................................... 64
Troubleshooting Sheets .............................................................................................................. 69

REU-2532W Series

Rinnai

Glossary of Terms and Symbols

This glossary of terms and symbols is provided to assist you in understanding some of the
language used throughout this manual.
DB(A)
DC
AC
WFCD
FB
Hz.
IC
BTU/H
PSI
LED
GPM
mA
W.C.
mm
Nox
OHS
PCB
CPU
POT
rpm
SV
∅
∆ °F
POV
TE
TH
TIN
Tout

REU-2532W Series

sound pressure level in decibels, “A” range
direct current
alternating current
water flow control device
feedback information
hertz
integrated circuit
British thermal units
Pounds per square inch
light emitting diode
gallons per minute
milliamps
inches of water column
millimeters
oxides of nitrogen NO & NO2
overheat switch
printed circuit board
central processing unit
potentiometer
revolutions per minute
solenoid valve
diameter
delta T or temperature rise above ambient
modulating valve
thermal efficiency
thermistor
temperature of incoming water
temperature of outgoing water

Rinnai

Introduction

The brand name Continuum refers to “Endless Hot Water”. The new Continuum series has been
developed in response to the growing changes in the lifestyle of our customers, and the increasing
diversification and sophistication of demand in the marketplace.
The Continuum series offers reduced cost with advanced safety features, and an option to connect one,
two, or three remote temperature control pads to the residential units. The commercial units only allow
one keypad per heater.
The Continuum REU-2532 series is delivered with the maximum hot water temperature output set at
120 °F without the remote control. When using controllers you can adjust your hot water output from 96
– 120 °F using the “BC” and “BSC” controllers. The “MC” control will allow water temperature
adjustments from 96 – 140 °F, and the “MCC” control used only with the commercial unit, allows
adjustments from 96 - 180°F. .
About the Continuum
The front cover of each appliance in the new series is formed from 0.6 mm coated steel. Secured to the
main box assembly by (4) screws. Seals around the front cover prevent water from entering the
appliance.
Air inlets are situated in the front panel of the 2532 external unit. Air passes through the inlets and is
drawn into the combustion chamber at the left side of the fan housing. The by-products of combustion
on the external unit are expelled from the appliance through the flue outlet situated on the front of the
appliance, at the top. The general layout of components can be seen in the cut-away diagram, see table
of contents for page number. All components are suppported within the unit’s casing, which is made
from 0.8 mm coated steel.
The heat exchanger occupies the top section of the casing, and the burner is situated in a chamber
formed from 0.8 mm aluminized steel, attached to the bottom of the heat exchanger. The copper tubing
material used in the heat exchanger consist of, Phosphorus Dioxide Copper, (C1220P). The material
used to solder the heat exchanger pipes is, Phosphorus Bronze Brazing, (main components are P, Ag,
and Cu) (JIS No. BcuP-2). None of these materials contain lead.
The air for combustion is supplied by a fan, which is connected to the burner box by a duct at the left
side of the appliance, directly under the burner.
Gas and water controls are situated at the bottom right of the appliance, directly under the manifold. The
“O”ring material on the water and gas connections are made from EPDM, (Ethylene Propylene Diene)
rubber.
The burner assembly is made up of (16) identical stainless steel Bunsen burners, secured by an
aluminized steel framework. Each burner is capable of handling up to 11,250 BTU’s. An aluminum
manifold with (32) integrally molded injectors supplies gas to the burners, and is attached to the front
lower cover of the burner box.
REU-2532W Series

Rinnai

Features

Installation
The lightweight, slim, compact design enables ease of installation and improved appearance. The remote
controls (where fitted) are connected to the appliance by (2) core non-polar cable, or low voltage
thermostat wire, ensuring easy wiring and eliminating problems of mis-connections. Since the remotes
use a 12 VDC digital signal, there’s no-way you can cross up the wiring. You can connect the black
wires to black wires at one terminal, black and white at another, and still not short the units out.

Low Noise Level
Low noise level design enables these appliances to be installed in apartment units, townhouses, and
other high density residential areas with little concern about noise disturbances.

Safety
Various safety devices controlled by a micro- computer ensure complete safety. Also, the anti-frost
device automatically prevents the water inside the appliance from freezing by using small electrical
ceramic heaters, connected to the pipe-work at strategic locations throughout the appliance. The unit has
a secondary freeze prevention device that will allow the unit to fire for three seconds if the water
temperature inside the appliance drops below 37 °F. This mode will heat the water inside the unit back
up to 57 °F. The anti-frost devices should prevent the unit from freeze-ups down to the –30 °F, in a no
wind situation. This feature functions as long as the unit has power and gas.

Economy
Direct ignition to the main burner eliminates wasteful pilot gas consumption. The combustion fan rpm is
proportionally controlled with the gas consumption. This maintains high energy efficiency, as the gas
consumption changes with increased or decreased water flows. The unit’s thermal efficiency rating is;
0.85 for (LP) units and 0.79 for natural gas units.

Water Supply Control
The water supply capacity varies proportionally from 0.5 to 8.5 GPM’s. A suitable volume of hot water
can be supplied throughout all seasons by the water flow control device and water flow
servomechanism. The Continuum 2532 series will supply up to 6.5 GPM’s at a 50°F rise or up to 8.5
GPM’s at a 35 degree rise, controlled by an automatic electro-mechanical water control flow device.
Details pertaining to water flows can be found in the water flow charts in this manual.

REU-2532W Series

Rinnai

Water Temperature Control
With an “MC” remote control connected, the hot water control range at the key pad is 96 – 140 °F. The
“BC” and “BSC” key pads allow for adjustments between 96 – 120 °F. The “MCC” key pad allows the
commercial unit to be adjusted from 96 – 180 ° F. This allows the Continuum to be set to comply with
various State codes pertaining to maximum water temperatures allowed for homes, child care centers,
elderly care centers, etc. where the water temperature can not exceed a certain set point.

Over Temperature Control
All Continuum models incorporate a device to prevent the hot water temperature from exceeding the
pre-set temperature by more than 4 °F.

Temperature Locks
With the remote control(s) connected, the pre-set water temperature can only be altered between 96 –
110 °F while water is flowing. Also, if the remote control circuit fails while water is flowing, the unit
defaults back to 100 °F. That prevents inadvertently increasing the temperature to a hazardous level
while someone is in the shower. This is an Anti-Scald feature.

REU-2532W Series

Rinnai

Dimensions

REU-2532W Series

Rinnai

Installation
Piping recommendation.

REU-2532W Series

Rinnai

Remote Controls

The MC45-4US, BC45-4US, BSC45-4US , and the MCC45-4US remote key pads were specifically designed
for use with the Continuum water heaters.

Features include:
Color coordination to allow immediate recognition of the temperature “hot” and “cold” buttons.
Large LED display. Temperature adjustments in two degree increments from 96 – 110 °F, then two five
degree increments from 110 – 115 °F , and 115 °F - 120 °F , on the BC, BSC and MC controllers.
The “MC” controller has two additional ten degree increments, from 120 to 130, and 130 to 140 °F.
The BC, BSC and MC controls are for domestic use. The MCC control allows the temperature to be adjusted
from 96°F - 180°F , this control is used only for commercial units.
Water temperature adjustment only in the range of 96 – 110 °F while hot water is flowing. Anti-Scald feature
defaults unit back to 100 °F, if remote fails or becomes disconnected while water is flowing.
Enhanced communication system between the remote controls, allowing priority temperature selection from
each remote control.
Remote controls offer self-diagnostics in the event of a fault with the unit, simplifying service calls. To
retrive the last ten error codes press and hold the green button down, while holding this button down press the
red button. This will gi ve you a fault code history. To reset, turn the power supply off to the unit , then
reapply power.
Flashes “LC” in the event of a liming condition. To reset the “LC” mode, power must be turned off to the
unit and then reapplied.

To measure the flow rate through the unit using the remote control, press the red button and hold it
down while the unit is operational, while holding the red button down press the green button. This
will give you the gallons per minute flowing through the heater.
To measure the water heater’s output water temperature press the blue button and hold it
down while the unit is operational, while holding the blue button down press the green button. This
will give you the water temperature being delivered by the unit.

REU-2532W Series

Rinnai

Suggested Connection Methods for Remotes

There must be at least one cable from the remote control(s) connected to the Continuum water heater.
Power for the remote(s) is supplied from the PC board. On the front of the PCB, there are two screws
labeled terminals for controls. This is the 12VDC digital power supply for the remotes. Use low voltage
thermostat wire when wiring up the keypads.

REU-2532W Series

Rinnai

Safety Devices

Flame Failure
Situated to the right of the burner in the front of the combustion chamber, the flame rod monitors the
combustion process. This sensor monitors the flame intensity, while the PCB compares this signal to the
feed back signal from the combustion fan motor, water flow control, and gas flow through the POV
valve. If any one of the feedback signals are incorrect, the unit will shut off, preventing discharge of
gas to the burner.

Over Heat Protection Device
Also referred to as an Over Heat Switch. This device is fitted to a bend section at the left side of the heat
exchanger. If the flame remains on to the burner after the tap is closed and the water temperature inside
the heat exchanger reaches 194 ° F, a 12 volt DC bi-metal cut-off switch will shut off the gas supply to
the solenoids.

No Water
Should the incoming water flow become restricted or stop, the water flow sensor will cease to send a
magnetic pulse signal to the PCB, in turn preventing gas to flow into the combustion chamber. If you
have restricted flow, first check to ensure the inline water filter is not clogged up.

Thermal Fuse
Wrapped around the entire surface of the heat exchanger you will find a thermal fuse. This device
activates in the event the heat exchanger burns out, or the temperature outside the heat exchanger
reaches 264 °F. If the thermal fuse melts, it breaks an electronic circuit which in turn shuts off the
power supply to the gas solenoids, shutting the unit off.

Combustion Fan Revolution Check
The combustion fan rpm’s are continually monitored by a magnetic pulse generator connected to the
PCB. If the fan revolutions deviate from the speed required for complete combustion, a signal is sent to
the PCB and the revolutions adjust accordingly. (If not the unit shuts down)

Automatic Frost Protection
When the temperature inside the appliance drops below 37 °F , the frost sensing device inside the
appliance activates the anti-frost heaters to prevent the water inside the unit from freezing. The antifrost heaters remain ON until the temperature inside the appliance rises to 57 °F. There are five (16) watt
anti-frost heaters located at various points throughout the main water flow area of the appliance. The
unit also incorporates the ability to fire for (3) seconds in the event the anti-frost heaters can not keep
the water temperature from dropping below 37 °F. This unique feature will heat the water in the lines
inside the appliance back up to 57 °F. Both of the above features function as long as the unit has
power and gas. There is an optional freeze protection system that can be added to the unit’s piping. See
the auto drain down drawing in the product Owner’s manual for instructions on how to install the option
freeze protection in the event of a power failure in cold climates.
REU-2532W Series

Rinnai

5 °F Over temperature Cut-Off
The temperature of the outgoing hot water is constantly monitored by the water temperature thermistor
located near the outlet of the appliance. If the outgoing water temperature reaches 5 °F above the preset
temperature, the burner will automatically go out. The burner will only ignite again once the outgoing
hot water temperature falls below the preset temperature.

REU-2532W Series

Rinnai

SPECIFICATIONS

Type of appliance
Operation
Exhaust system
Rinnai model number
Maximum/Minimum gas rate (Input
Btu’s)
Thermal Efficiency
Energy Factor (EF)
Capacity (Gallons 1st. Hour @ 90 ºF
rise)
NOx Emissions (at 3% 02 )
Hot water capacity (35°F rise)
Hot water capacity (50°F rise)
Setpoint Temperature (without
remote)
Temperature range with remote
keypads connected
Approved gas type
Installation
Dimensions

Weight
Noise levels
Connections

Ignition system
Electrical consumption

Water temperature control
Water flow control
Recommended Minimum water
supply pressure
Maximum water supply pressure

REU-2532W Series

Temperature controlled continuous flow gas hot water system
With/without remote controls
Direct Vent - Forced combustion
REU-2532W
REU-2532W-C
199,000 Btu’s – 15,000 Btu’s Natural gas
199,000 Btu’s – 15,000 Btu’s Propane Gas
Natural Gas 84%.
Propane Gas 85%
Natural Gas 0.82
Propane Gas 0.84
Natural Gas 218
Propane Gas 227
Less than 40 ppm
0.5 to 8.5 GPM’s
0.5 to 6.5 GPM’s
Factory setting - 120°F
BC-45-4US
96 - 120°F
MCC-45-4US 96 - 180°F
BSC-45-4US 96 - 120°F
MC-45-4US
96 - 140°F
Natural or Propane – Ensure unit matches supply gas type.
Outdoor installation ONLY
Height
235/8”
Width
133/4”
Depth
87/8”
46 Lbs.
49 dB’s
Gas supply
¾” MNPT
Cold water inlet ¾” MNPT
Hot water outlet
¾” MNPT
Direct electronic ignition
Normal
63 watts
Standby
5.5 watts
Anti-frost protection
84 watts
Simulation feedforward and feedback
Water flow sensor and automatic electro-mechanical water
control devise
20 PSI (Rinnai recommends 50-80 PSI for maximum
performance)
150 PSI

Rinnai

Specifications cont.
Power Supply
Safety Devises

Remote control

Remote control cable
Clearances from combustibles

Clearances from non combustibles

Appliance – 120 Volts A.C. – 60 Hz.
Remote control 12 volt D.C. (Digital)
Flame failure
Boiling protection
Remaining flame (OHS)
Fusible link
Automatic frost protection
Combustion fan rpm check
Over current
MCC-45-4US
BC–45-4US
BSC-45-4US
MC-45-4US
Non-polarized two core cable
Top of heater
Front of heater
Sides of heater
Back of heater
Ground
Top of heater
Front of heater
Sides of heater
Back of heater
Bottom of heater
Installations within RGB-25 Recess Box: Clearances
from combustibles to recess box top, bottom, back and
sides = 0”
Top of heater
36”

Clearances from Eaves, Porches,
Overhangs
Minimum and maximum gas supply Natural Gas: Minimum 6” W.C.
pressure
(NAT.)
Maximum 10.5”
W.C.
Manifold Gas Pressure
Warranty

REU-2532W Series

Rinnai

Cut-way Diagram

REU-2532-FFU Series

REU-2532W Series

Rinnai

10.

Schematic Diagram

REU-2532W Series

Rinnai

11.

Combustion Specifications

Model: REU-2532W Series
Item
Gas Type
Gas consumption
Injector Diameter
Main Burner
Main Damper
Gas Pressure
Supply/Manifold

REU-2532W Series

Natural

Propane

Minimum Btu’s
Maximum Btu’s
Upper
Lower

15,000
15,000
199,000
199,000
Ø1.15
Ø0.75
Ø1.8
Ø1.15
B3A7-1
(Lean and Rich Bunsen Burner)
H73-115
(Upper: Ø6, Lower: Not Used)
Minimum Supply
6” W.C.
10” W.C.
Maximum Supply
10.5” W.C.
13.5” W.C.
Minimum Manifold 0.56” W.C.
0.88” W.C.
Maximum Manifold 3.4” W.C.
5.1” W.C.

Rinnai

12.

DIP SWITCHES

Contact Rinnai for dip switch settings when changing PC board or setting up unit for special applications. Failure to set dip
switches to the proper position will result in damage to the unit, property damage, personal injury or death. DO NOT,
adjust dip switches unless you have written permission from Rinnai. Call 1(800)621-9419 to set-up a special training class
pertaining to dip switch functions.
The dip switches on this appliance can be adjusted to deliver water temperatures from 108°F - 180°F, only for commercial
type applications, and to check/reset low/high fire manifold pressures, and to set the unit up to operate on a different gas
type in the event the unit was converted from one gas type to another. In residential applications these switches should
never be readjusted from the factory setting. The factory default temperature setting is 120°F.
The set-up configuration for the water heater differs depending on:
Gas type
Maximum water flow selected
Temperature limiting requirements
Application type
“SW1” row of dip switches
1. Not Used
2. Fixed water temperature with or without remote.
3. To select a desired water temperature for commercial applications
4. To select a desired water temperature for commercial applications
5. To select a desired water temperature for commercial applications
6. Flow switch activated or de-activated and temperature selection for commercial applications.
7. Combustion control (Forced low fire).
8. Combustion control (Forced high fire).
Combustion control switches are used to set or check the manifold gas pressures on this appliance. When dip
switch #7 is placed in the “ON” position, it places the appliance into forced low fire. When dip switches #7 and
#8 are placed in the “ON” position, it places the unit into forced high fire. Before placing the unit into forced
low or high fire, you MUST ensure you have maximum water flow through the appliance. Open several
faucets throughout the residence before proceeding. After checking or setting manifold gas pressures, dip
switches 7 and 8 MUST be placed in the “OFF” position, to return the appliance to a normal operating
mode. Failure to place these switches to the “OFF” position will cause the unit to mal-function.
The REU-2532 series water heaters comes from the factory set to deliver a water temperature of 120 °F, the REU-2532-C
series is set to deliver 120°F. However, the commercial series will allow water temperature adjustments up to 180°F for
applications such as; hotels, car washes, laundry mats, hospitals, farms, processing plants, etc., that require water
temperatures above 120°F. Temperatures above 120 °F are not recommended due to burn hazards. Please use extreme
caution if adjusting water temperatures above 120 °F.

Explanation of “SW1” Dip Switches;

(Switch #1)

at SW1” row of switches comes from the factory in the “OFF” position. This switch presently is not used.

(Switch #2) Fixed Water Temperature with or without Remote. When this switch is set to the “OFF” position, switches
3 – 6 can be adjusted to a pre-determined position that will not allow the remote pad to be adjusted above a selected
temperature. When set to the “ON” position and no keypad is being used, the unit can be set to deliver a set temperature
from 108, 120, 130, etc. DO NOT make adjustments without written permission from Rinnai.

REU-2532W Series

Rinnai

(Switches 3,4, & 5) Temperature Adjustment Switches. Switches #3, 4, and 5 are used to set fixed temperatures with or
without the remote keypads. Contact Rinnai for dip switch settings when changing the unit’s PC board or setting up special
applications. Failure to set dip switches to the proper position will result in damage to the unit, property damage,
personal injury or death. DO NOT, adjust switches unless you have written permission directly from Rinnai. Call
1(800)621-9419 to set-up a special training class pertaining to dip switch functions.
(Switch #6) Flow Switch and Temperature Adjustments. Rinnai offers a flow switch that can serve as an anti-scald
device. This switch is installed in-line with each bathroom. Therefore, if someone was using water above 120°F and a tap
was turned on in one of the bathrooms, the unit would automatically default back to 120°F to prevent scalding. When dip
switch #6 is set to the “ON” position this function is activated. At the present time this switch is not used in the U.S.
market, due to anti-scald devices and/or pressure balancing valves presently being used in our market.
(Switches 7& 8) Low/High Fire Combustion Control Switches. Dip switch # 7 is used to place the unit into forced low
fire when checking and/or setting manifold gas pressures. Dip switch #7 and #8 are used to place the appliance into forced
high fire. Before making any adjustments to these switches, please ensure you follow the gas pressure setting procedure
found in this manual.

“SW2” row of Dip Switches
1. Gas type (Used only when replacing PCB or converting unit)
2. Lime control switch activated or de-activated.
3. Plus three degrees or plus six degrees differential.
4. Type of unit. (Residential or commercial)
(SW2) Explanation of SW2 row of Dip Switches
(Switch #1) Gas Type Switch. When set to the “OFF” position the unit is setup to operate on propane gas, in the “ON”
position it is setup for natural gas.
(Switch #2) Lime Control Switch. Set dip switch #2 to the “OFF” position to activate the lime control function. To
deactivate this function place this switch in the “ON” position.
(#3) Temperature Differential Switch. The temperature of the outgoing water is constantly monitored by the outlet
temperature thermistor. If the outlet water temperature rises to more than 5.4°F above the preset temperature, the burner
will automatically go out when dip switch #3 is in the “OFF” position. The burner will ignite again once the outlet water
temperature falls below the preset temperature. If this switch is set to the “ON” position it will allow a 10.8 °F rise.
(Switch #4) Type of Unit. Danger; do not adjust this dip switch. Adjusting this will result in damage to the unit,
property damage, personal injury or death.

REU-2532W Series

Rinnai

Rinnai Continuum and Integrity Water Heaters
Dip Switch Default Settings
The settings below are factory default settings. Please ensure the model number and gas type of the unit
you have, matches the model number and gas type listed below; before settings any switches. If you need
assistance, contact Rinnai at (800)621-9419 before proceeding.

Residential Units

REU-2532-W
Propane Gas Model
Dip Switch Settings:
(SW1)
#1 = Off
#2 = On
#3 = Off
#4 = Off
#5 = Off
#6 = Off
#7 = Off
#8 = Off

REU-2532-W
Natural Gas Model
Dip Switch Settings:
(SW1)
#1 = Off
#2 = On
#3 = Off
#4 = Off
#5 = Off
#6 = Off
#7 = Off
#8 = Off

(SW2)
#1 = Off
#2 = Off
#3 = Off
#4 = Off

Commercial Units
REU-2532-WC
Propane Gas Model
Dip Switch Settings:
(SW1)
#1 = Off
#2 = On
#3 = Off
#4 = Off
#5 = Off
#6 = Off
#7 = Off
#8 = Off

REU-2532W Series

(SW2)
#1 = On
#2 = Off
#3 = Off
#4 = Off

Commercial Units

REU-2532-WC
Natural Gas Model
Dip Switch Settings:
(SW1)
#1 = Off
#2 = On
#3 = Off
#4 = Off
#5 = Off
#6 = Off
#7 = Off
#8 = Off

(SW2)
#1 = Off
#2 = Off
#3 = Off
#4 = On

(SW2)
#1 = On
#2 = Off
#3 = Off
#4 = On

Rinnai

13.

Water Flows

A simple calculation of the water flow rate, in gallons per minute, can be made using the chart on the
next page, or simply using formula provided below. The chart on the following page indicates the water
flow from the Continuum at various temperature rises up to a 140 degree rise.
a. How to read the charts:
The vertical plane indicates water flow in gallons per minute, and the horizontal plane indicates the
temperature rise. The chart shows flow rates up to a 140 degree rise. Therefore, the water flow chart can
be used to help you size your applications, if you know the temperature rise needed. The temperature
rise is the difference between the temperature of the incoming water and the selected temperature at the
remote control(s). Another name used in place of temperature rise, is delta T.
Select the appropriate temperature rise. Draw a vertical line up the graph from the selected temperature
rise until it intersects the curve. The point at where these lines intersect indicates flow at that
temperature rise.
b. How to calculate water flows:
The following information is an outline of the formula required to measure accurately the flow rate in
gallons per minute, as well as being the base for the chart on the next page. The formula below can be
utilized when you know the following information, the Btu’s and efficiency of the appliance, and the
delta T you are dealing with. If this information is known follow the example below to determine your
flow rate. The example below assumes the appliance’s Btu rating is 180,000, the efficiency is .82 and
the delta T is 55 degrees.

EXAMPLE:
BTU’s ÷ AT x 500 = GPM’s
GPM’s = (180,000 BTU’s x .82 efficiency rating) ÷ ÄT x 500
GPM’s = 147,600 ÷(Requested water temperature – incoming water temperature) x 500
GPM’s = 147,600 ÷ (120 °F requested – 65 °F incoming) x 500
GPM’s = 147,600 ÷ (55 °F delta T x 500)
GPM’s = 147,600 ÷ 27,500
GPM’s = 5.367

REU-2532W Series

Rinnai

Unmixed Water Flows for REU-2532 Series

The chart below can be used to determine water flow rates in “gallons per minute” at a given
temperature rise. In order to figure flow rates, you need the following information; requested water
temperature and inlet water temperature. Next, subtract the inlet water temperature from the requested
temperature to get your delta T or temperature rise. Then, locate your temperature rise at the bottom of
the chart. Follow that line vertically until it intersects with the flow rate line to the left. This indicates
the flow rate at your temperature rise.

REU-2532W Series

Rinnai

14.

Main Components

Mechanical Water Regulator

Rinnai’s unique water regulator mechanism ensures the hot water is maintained with no noticeable
change to the desired temperature during use, even if water pressure drops due to another tap being
turned on and increasing the demand.
The following graph shows that maximum flow is approximately 8.5 gallons per minute for the
Continuum. This maximum flow is reached at 29 PSI inlet pressure respectively.

Preset Bypass

A preset volume of cold water is mixed with water heated in the heat exchanger.
3.

Burner

The burner assembly is made up of 16 identical stainless steel
Bunsen burners, secured by an aluminized steel framework.
An aluminum manifold with 32 integral injectors supplies gas
to the burners, and is attached to the front lower cover of the
burner box and gas control assembly.
4.

Gas Control Valve

The gas control valve uses four solenoids to fully modulate within four different input ranges to
respond quickly and accurately to changes in water flow rate. The four ranges are as follows: up to
18% of total btu’s (using three burners), up to 33% (using five burners), up to 50% (using eight
burners, and up to 100% (using sixteen burners) This increases the flexibility of the regulator/
modulating valve by supplying gas equally to each burners.
REU-2532W Series

Rinnai

Combustion Fan

Air for the combustion is supplied by a centrifugal fan
driven by a DC motor. After a pre-purge period of 0.2
seconds, the fan speed is controlled by the PCB to
provide the correct volume of air for combustion. The
calculation for the fan speed is based upon incoming
water temperature, water flow and the temperature
selected on the remote controls.
The actual speed of the motor is continuously monitored
by a magnetic pulse sensor.
This sensor emits (4) pulses per rotation of the fan. This is
the fan feedback or confirmation data processed by the PCB.
1. The fan speed is constantly correcting to provide optimum combustion conditions.
2. To determine the opening degree of the modulating gas valve, so that the gas rate always matches the volume
of air for combustion, as well as the input required to heat the water.
The reason for controlling the opening degree of the modulating gas valve based upon data from the combustion
fan is that, the gas valve is able to react much more quickly to a change in control signal than the combustion fan
is. Controlling the gas valve based upon data from the combustion fan means that combustion remains
satisfactory, even if there are sudden changes in input conditions.

Water Flow Sensor and Water Flow Control device

Water flow is detected by a turbine/magnetic pulse generating device. Water flows through the turbine/magnetic
sensor providing information to the PCB by generating a pre-determined number of pulses in proportion to the
water flow. These pulses are counted by the PCB – no pulse indicates no water flow. The frequency of the
magnetic pulses increases as the water flow increases, this enables the PCB to calculate the exact water flow, and
determine the water flow in gallons per minute. As soon as the required water flow is detected, the PCB activates
the combustion fan. The combustion fan speed is monitored by a magnetic pulse sensor. The output from this
sensor is processed by the PCB which opens the gas modulating valve to a degree proportional to the fan speed.
See above for further details on the combustion fan.
The water flow control consists of a plug and barrel valve which is rotated by a motor to increase or decrease the
volume of water passing through the heat exchanger.
REU-2532 units have an automatic water flow control device.

REU-2532W Series

Rinnai

15.

Time Charts

REU-2532W Series

(External Unit)

Rinnai

REU-2532W Series

Rinnai

16.

Operation Flow Principle
Check power supply

Fuses/electrical
circuit operational

Eliminate cause

Disconnect power
supply

Yes

Remote control indicates no
flow OFF

Remote control
signal normal?

Yes

ON/OFF Switch

ON/OFF switch ON
Error display

OFF

Set Temperature displayed
Water flow sensor stopped

A
Hot water tap open

Hot water tap closed

Error code displayed on remote

water flow greater
than 0.6 gpm's

Yes

OFF

(after 5 seconds)
No

combustion fan operates

Combustion fan

Fan initial power flow abnormal

90 Flashing

Combustionfan rpm's abnormal

61 Flashing

Failed to sense flame circuit

72 Flashing

Solenoid valve circuit faulty

71 Flashing

Modulating solenoid valve faulty

52 Flashing

Thermistor faulty

32 Flashing

Combustion fan pre-purges

6
Initial check
normal?

Yes

Fan rpm check

Thermo fuse melted

Overheat bi metal switch faulty

14Flashing
61 Flashing

Not OK

(12.5 seconds after A)
Yes
Pre-purge of combustion fan
(2 seconds)

9
10

Sparker

ON
Sparker

Solenoid valve SV0

OPEN

Main gas valve SV1

OPEN

Solenoid valve SV2

OPEN

Solenoid valve SV3

Modulating valve

Closed

Solenoid valve SV0

Closed

Solenoid valve SV1

Closed

Solenoid valve SV2

Closed

Solenoid valve SV3

Closed

OFF

Modulating valve

Closed

Solenoid valve SV0

Closed

Solenoid valve SV1

Closed

Solenoid valve SV2

Closed

OPEN
Solenoid valve SV3 Closed
(after 4 seconds)

REU-2532W Series

Rinnai

Flame
detected (1
micro amp
or g re ater)

Yes
Ignition failure
(3 a ttempts)

11 Flashing

No Combustion

12 Flashing

10 Flashing

32 Flashing

61 Flashing

10 Flashing

Flame failure (less
than 1 micro amp)

Water temperature
over 200 degrees

Thermistor faulty
(open or
short-circuit)

Combustion fan
rpm's abnormal

Flue restriction or
block

Yes
Sparker

OFF

Combustion proved
Gas solenoid open

14 Flashing

12 Flashing

52 Flashing

71 Flashing

Check grounding,
venting, and gas
pressures.

Modulating solenoid
valve abnormal

SV0, SV1, SV2, or
SV3 solenoid valve
circuit abnormal

Hot water is sensed
Water flow servo
operational
Combustion fan
operational
Modulating valve
operational
Gas solenoids
operational

Safety circuit
operational

Thermal fuse melted
Overheat switch
activated

Yes

REU-2532W Series

Rinnai

17.

Operation Principles

The preset temperature is selected at one of the remotes controls (where fitted). Where no remote control is
fitted , the default temperature can be set at 108, 120, 130, 140, 150, 160, 170, or 180 °F. To select one of
the above temperatures as your default setting, you MUST obtain written permission and training from
Rinnai. This function may not be allowed at temperatures above 120°F for safety reasons.
When the unit is first plugged into 120 volts, the PCB assumes an incoming water temperature of 77 °F.
This prevents the appliance from starting in “High fire” and producing very hot water the first time it is
used.
The data used to determine the outgoing water temperature, initially, is incoming water flow and the remote
control pre-set temperature.
From the incoming water flow and remote control pre-set temperature data, the CPU is able to determine a
suitable gas rate to kick the appliance off once a hot water tap opens.
The calculation of temperature rise and water flow is called simulation feed-forward.
The water heater calculates incoming water temperature by subtracting the theoretical temperature rise
from the outgoing hot water temperature to establish the correct gas flow.
When a hot water tap is opened, water begins to flow through the appliance. The turbine in the water flow
sensor begins to revolve. The revolution speed is proportional to the heater flow. A sensor located inside
the device relays information in the form of magnetic pulses to the main PCB to determine whether or not
water is flowing, and also, the volume of water flowing. When a predetermined water flow is sensed, the
ignition sequence begins.
The combustion fan pre-purges the combustion chamber. A rev counter on the combustion fan indicates
the fan rpm to the main PCB. Once the pre-purge cycle is completed, the PCB controls the fan rpm by
varying the DC voltage to the fan motor. This maintains the correct air/gas ratio throughout the time the
water heater is in use and ensures good combustion.
The gas is ignited by direct electronic spark and the flame is sensed by the flame rod. The opening degree
of the modulating valve is determined by the combustion fan speed.
The changeover valve directs gas to one side or both sides of the burner. At the point where the changeover
valve opens or closes the modulating valve is instantly re-adjusted by the PCB to compensate for the
change in the number of burners in use. From the information provided by the water flow sensor and the
water temperature thermistor, the PCB determines how much gas is required to heat the water to the
temperature selected on the remote control.
The PCB is programmed to provide the maximum volume of water possible at a given temperature rise. As
the water flow from the tap is increased, the PCB increases the gas and air flow to the burner.
REU-2532W Series

Rinnai

When the hot water tap is turned off, the water flow sensor stops revolving, and the magnetic pulse ceases,
indicating to the PCB that there is no water flowing, in turn the PCB closes the gas valves. The combustion
fan continues to operate for 65 seconds. This is to provide quicker ignition when the tap is turned on and
off in rapid succession, as it removes the need for a pre-purge cycle and allows the burner to re-light
immediately when a hot water tap is opened again.

REU-2532W Series

Rinnai

18.

Error Codes
Error

Faulty

Remedy

Air Supply or Exhaust
Blockage

No Ignition

Flame Failure

Thermo Fuse

Over Temperature
Warning

Check intake and exhaust ports for obstructions.
Check that nothing is blocking the flue inlet or exhaust.
Did you maintain the proper clearance from combustibles
around the unit?
Ensure you have gas to the appliance.
Ensure gas type and pressure is correct.
Bleed all air from gas lines.
Verify dip switches are set properly.
Disconnect all MSA controls.
Ensure gas line, meter, and/or regulator is sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Ensure igniter is operational.
Check igniter wiring harness for damage.
Ensure you have gas to the appliance.
Ensure gas type and pressure is correct.
Bleed all air from gas lines.
Verify dip switches are set properly.
Ensure flame rod wire is connected.
Check flame rod for carbon build-up.
Ensure gas line, meter, and/or regulator is sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Check power supply for loose connections.
Check power supply for proper voltage and voltage drops.
Disconnect all MSA controls.
Disconnect keypad.
Disconnect and re-connect all wiring harnesses on unit and PC
board.
Immediate code 12 usually indicates a defective gas valve or
power supply problem.
Ensure dip switches are set to the proper position.
Ensure high fire and low fire manifold pressure is correct.
Check gas type of unit and ensure it matches gas type being
used.
Check heat exchanger for cracks and/or separations.
Ohm out safety circuit.
Check for improper conversion of product.
Check for restrictions in air flow around unit and vent terminal.
Check for a low flow circulating system that is causing the unit
to short cycle.
Check for a foreign materials in combustion chamber and/or
exhaust piping.
Check for clogged heat exchanger.
Check for restrictions in air flow around unit and vent terminal.
Check for a low flow circulating system that is causing the unit
to short cycle.
Check for a foreign materials in combustion chamber and/or
exhaust.

REU-2532W Series

Rinnai

Outgoing Water
Temperature Sensor Faulty

Heat Exchanger Outgoing
Temperature Sensor Faulty

Combustion Air
Temperature Sensor Faulty

Modulating Solenoid Valve
Answer Abnormal

Combustion Fan Failure

SV0, SV1, SV2, and SV3
Solenoid Valve Circuit
Faulty
Flame Sensing Device
Faulty

Scale Build-up in Heat
Exchanger

No code

Nothing happens when
water flow is activated.

REU-2532W Series

Check sensor wiring for damage.
Ohm out sensor
Check and clean scale from sensor.
Replace sensor.
Check sensor wiring for damage.
Ohm out sensor
Check and clean scale from sensor.
Replace sensor.
Check sensor wiring for damage.
Ohm out sensor
Check and clean scale from sensor.
Ensure fan blade is tight on motor shaft and it is in good condition.
Check for restrictions in air flow around unit and vent terminal.
Replace sensor.
Check modulating gas solenoid valve wiring harness for loose or damage
terminals.
Ohm out solenoid valve.
Ensure fan motor will turn freely. Motor will operate with a small amount of
restriction.
Check wiring harness to motor for damaged and/or loose connections.
Ohm out motor winding.
Check wiring harness to all solenoids for damage and/or loose connections.
Ohm out each solenoid.
Check micro amps produced by flame rod.
Remove flame rod and check for carbon build-up, clean will sand paper.
Ensure flame rod is touching flame when unit fires.
Check inside burner chamber for any foreign material blocking flame at flame
rod.
Check all wiring to flame rod for damage.
Replace flame rod.
Turn off power supply, then reapply power; if code does not reappear separate
control wires from the unit’s power supply.
Flush heat exchanger.
Replace heat exchanger.
Clean inlet water supply filter.
Ensure you have at least the minimum flow rate required to fire unit.
Check for pipe dope inside water flow control turbine.
On new installations ensure hot and cold water lines are not crossed.
Check for bleed over. Isolate unit from building by turning off hot water line
to building.
Then open your pressure relief valve, if unit fires, there’s a bleed over in your
plumbing.
If a circulating system is in use, it must be isolated also.
Remote control does not light up but you have 12 VDC at the terminals for
controls.
Disconnect water flow control motor, then turn on hot water, if unit fires
replace water
flow control assembly.

Rinnai

19.

Diagnostic Points

Flow Chart is on page #28
Wiring Diagram is on page #35

Component
Surge Protector

Measurement Point

Blue - Brown

AC 108 - 132 V

Red-Blue

DC 11 - 13 V

Power Supplied to Unit

DC 11 - 13 V

Power Supplied to Unit

Gray-Yellow

Gray-Brown

By-pass Flow Control Device

Remote Control

Water Flow Sensor

Combustion Fan

Below DC 1 V (Limiter On)
DC 4 - 6 V (Limiter Off)
Below DC 1 V (Limiter On)
DC 4 - 6 V (Limiter Off)

Modulating Valve

Full Close Position

Brown-White
Orange-White
Yellow-White
Red-White Gnd

DC 2 - 6 V

Black-Black

DC 11 - 13 V

Red - Black

DC 11 - 13 V

On 0.82 gal/min (30 Hz)
Over 1800 pulse/min

Yellow - Black Gnd

DC 4 - 7 V (Pulse 17-460 Hz)

Off 0.6 gal/min (20 Hz)
Below 1200 pulse/min

Unit In Operating Mode

15 - 35 kΩ

Red-Black

DC 6 - 45 V

Yellow-Black

DC 11 - 13 V

White-Black Gnd

DC 6 - 45 V (33-400 Hz)

Yellow-Gnd

AC 5 - 150 V

After Ignition

Yellow-Flame Rod

Over DC 1 µA

Flame Condition

Pink-Pink

DC 2 - 15 V
67 - 81 Ω

Air Thermistor

White-White

59°F 11.4 - 14.O KΩ
86°F 6.4 - 7.8 KΩ
113°F 3.6 - 4.5 KΩ
140°F 2.2 - 2.7 KΩ
221°F 0.6 - 0.8 KΩ

Thermal Fuse

B3
C3

Red-Red

Below 1Ω

Ignitor

Gray-Gray

AC 90 - 110 V

Heat Exchanger
Outgoing Thermister

Full Open Position

Flame Rod

Outgoing Thermistor

Notes

Wire Color

Gray-Orange
Water Flow Control Device

Normal Value

Comp. No.

B5
White-White
B6

Main Solenoid Valve

Pink - Black

DC 80 - 100 V
1.7 - 2.1 KΩ

Solenoid Valve 1

Yellow - Black

DC 80 - 100 V
1.7 - 2.1 KΩ

Solenoid Valve 2

Blue-Black

DC 80 - 100 V
1.7 - 2.1 KΩ

Solenoid Valve 3

Brown - Black

DC 80 - 100 V
1.7 - 2.0 KΩ

TRANSFORMER VOLTAGES AND RESISTANCES
Primary Windings

Blue-Brown

51 - 63 Ω

Secondary Windings

White-Black

AC 90 - 110 V

REU-2532W Series

Rinnai

20.

REU-2532W Series Wiring

REU-2532W Series

Rinnai

21.

Block Diagram

REU-2532W Series

Rinnai

22.

Electrical Component Analysis

Before carrying out checks marked with a # sign, disconnect power supply.
Unit’s wiring diagram can be found on page 35.

Appliance fails to operate (even remote control fails to operate).
1) Is the fuse blown
Check fuse.

Fuses are located in plastic
holders in the main harness,
on the lower right hand side
of the appliance.

a. Disconnect unit from power supply.
b. # Measure resistance to check the electric fuse (3
amp)
Normal: less than 1Ω
If normal, proceed to check item 2 below.
Faulty: Replace 3 amp glass fuse. If the fuse
blows again, investigate cause of short
circuit.

2) Is the main transformer normal ?
Check the transformer.
a. Measure the voltage and/or resistance at
connector F, black ~ white wires.
Normal: 100 ~ 120 VAC
51 ~ 63 Ω resistance
Faulty: Check for 120 – 125 VAC at the surge
protector, blue ~ brown wires, connector
F7.
Resistance reading 51 ~ 63 Ω
If normal, check item 3 on next page.
Faulty: Replace the transformer.

REU-2532W Series

Rinnai

3) Is the remote control normal ?
Check voltage between the two remote control
cable connectors.
a.

Check the voltage between terminals on
the remote control terminal mount D1.
Normal: 11 ~ 13 VDC
If normal, check for an open circuit or
short before replacing the remote control.
Faulty: Replace PCB.

No combustion (despite remote control indication)
1) Is the water flow sensor normal ?
Check the water flow sensor.
a. Check the voltage at PCB connector B4, red
and black wires.
Normal: 11 ~ 13 VDC or 5.8 ~ 6.4K Ω
If normal, check (b) below.
Faulty: Replace the PCB.
b. Check the voltage at PCB connector B4,
yellow and black wires.
Normal: 4 ~ 7 VDC or 1M ~ 1.2M Ω.
If normal, proceed to check item 2 on next
page.
Faulty: Replace the water flow sensor.

REU-2532W Series

Rinnai

2) Is the flame rod normal ? Error “72” is displayed
Checking the flame rod.
a. # Detach the flame rod terminal C1, and
re-attempt operation.
(“72 is displayed)
Proceed to check item 3 below.
(no “72” displayed)
Inspect flame rod wiring for current leak and
inspect flame rod for carbon build-up.
Measure resistance between the flame rod
Terminal C1 and the appliance earth.
Normal: 1 MΩ or more.
If normal, replace the PCB unit.
Faulty: Replace the flame rod.

See page 43 for additional information and
reading pertaining to the flame rod.

3) Is the water temperature thermistor normal ?
If error “32” is displayed, check the water
temperature thermistor.
a. # Disconnect connectorB5, and measure
resistance of the white ~ white wires.
Resistance > 1 MΩ = open circuit.
Resistance < 1Ω = short circuit.
Normal: Proceed to check item 4 on the
next page.
Faulty: Replace the water temperature
thermistor.

See page 44 for additional information and
reading pertaining to the temperature
thermistor. .

REU-2532W Series

Rinnai

4) Is the combustion fan motor normal ?
Motor check.
If error “61” is displayed, check the combustion
fan.
a. Measure voltage at connector A1. Black and red
wires.
Normal: 6 ~ 45 VDC (Fan on)
0 VDC (Fan off)
If normal, check item b below.
Faulty: Replace the PCB unit.
Fan revolution sensor check.
b. Measure voltage at connector A1, black and
yellow wires.
Normal: 11 ~ 13 VDC or 3.1 ~ 3.7 KΩ
If normal, check item c below.
Faulty: Replace the PCB unit.
c. Measure voltage at connector A1, black and
white wires.
Normal: 6 ~ 45 VDC or 9 ~ 9.4 KΩ
(33 ~ 400 Hz.)
If normal, proceed to check item 5 below.
Faulty: Replace the combustion fan motor.

5) Is the sparker operating normally ?
Check the sparker module.
a. Measure voltage at connector F8, grey and grey
wires.
Normal: 90 ~ 110 VAC
0 VDC (when fan is off)
If normal, check b below.
Faulty: Replace the PCB unit.
b. # Disconnect connector F8, and measure the
resistance between the two sparker terminals.
Normal: > 1 MΩ
Faulty: Replace the igniter module.
Electrode gap should be 3/16” to 1/4” .
.

REU-2532W Series

Rinnai

6) Is the main gas solenoid valve (SV0) operating normally ?
If error “11” or “71” is displayed, check the main
gas solenoid valve.
a. # Disconnect the main gas solenoid valve (SV0)
connector and measure the resistance at the
solenoid terminals.
Normal: 1.7 ~ 2.1 KΩ
If normal, check b below.
Faulty: Replace the main gas solenoid valve.
b. Measure voltage at the main gas solenoid (SV0)
Pink and black wires.
Normal: 80 ~ 100 VDC
If normal, proceed to check item 7 below.
Faulty: Replace PCB unit.

7) Is the change over solenoid (SV1) operating normally ?
If error “11” or “71” is displayed, check the change
over solenoid (SV1).
a. # Disconnect the change over solenoid (SV1)
connector, and measure resistance at the
solenoid terminals.
Normal: 1.7 ~ 2.1 KΩ
If normal, check b below.
Faulty: Replace the change over solenoid (SV1).
b. Measure voltage at the change over solenoid
(SV1) yellow ~ black wires.
Normal: 80 ~ 100 VDC
If normal, check 8 below.
Faulty: Replace PCB unit.

8) Is the change over solenoid (SV2) operating normally?
If error “11” or “71” is displayed, check the change
over solenoid (SV2).
a. # Disconnect the changeover solenoid (SV2)
connector, and measure the resistance at the
solenoid terminals.
Normal: 1.7 – 2.1 KΩ
If normal, check b below.
Faulty: Replace the changeover solenoid (SV2).
b. Measure the voltage at the changeover solenoid
(SV2), blue – black wires.
Normal: 80 – 100 VDC
If normal, check 9, on next page.
Faulty: Replace the PCB unit.

REU-2532W Series

Rinnai

9) Is the change over solenoid (SV3) operating normally?
If error “11” or “71” is displayed, check the change
over solenoid (SV3).
a. # Disconnect the changeover solenoid (SV3)
connector, and measure the resistance at the solenoid
terminals.
Normal: 1.7 – 2.1 KΩ
If normal, check b below.
Faulty: Replace the changeover solenoid (SV3).
b. Measure the voltage at the changeover solenoid
(SV3), brown – black wires.
Normal: 80 – 100 VDC
If normal, reconfirm gas pressures are correct..
Faulty: Replace the PCB unit.

REU-2532W Series

Rinnai

Error code “14” Check the thermal fuse.
a. # Disconnect connector B3 and C3, measure the
resistance between the red – red wires.
Normal: Less than 1Ω
If normal, check b below.
Faulty: Check manifold gas pressure. Check heat
exchanger for cracks and/or separations. If
there is nothing abnormal, replace the thermal fuse.

b. Check bi-metal switch, (remaining flame safety
device). Measure resistance between the two
terminals at B3 and C3.
Normal: 100 – 120 VAC
If normal, process to item a below.
Faulty: Replace the bi-metal switch.

Combustion stops due to flame failure
1) Is the flame rod functioning normally ?
a. Measure the voltage between the flame rod
terminal C1 and the appliance earth.
Normal: 5 – 150 VAC from yellow to ground.
If normal, check b below.
Faulty: Replace the PCB unit.
b. Check that the flame rod attachment is not loose.
Normal: Replace the PCB unit.
Faulty: Secure the flame rod bracket.

2) Is the earth lead wire connected ?
a. Check for defective earth terminal, or an open
circuit or short. If normal, investigate other possible
causes for the flame failure.
(Eg. Is the gas valve open ? Is the filter mesh
blocked ?) Was proper venting material used? Did
you regulate your gas supply pressure to the proper
gas pressure for gas type being used?
Faulty: Ensure unit is properly grounded. Check
ground circuit outside home at service pole. There
should be an eight foot ground rod driven in the
earth and a copper lead tied to the service meter.
Ensure connection on ground rod is tight.

REU-2532W Series

Rinnai

Unable to adjust hot water temperature
1) Is the water temperature thermistor operating normally ?
a. # Disconnect the connector B5, and measure the
resistance between the white wires, see below
for resistance readings.
Thermistor resistance valves:
59 ºF = 11.4 ~ 14 KΩ
86 ºF = 6.4 ~ 7.8 KΩ
113 ºF = 3.6 ~ 4.5 KΩ
140 ºF = 2.2 ~ 2.7 KΩ
221 ºF = 0.6 ~ 0.8 Ω
Normal: Proceed to check item 2 below.
Faulty: Replace the water temperature
thermistor.
2) Is the change over solenoid (SV1) normal ?
a. # Disconnect the changeover solenoid (SV1)
connector, and measure resistance at the
solenoid terminals.
Normal: 1.7 ~ 2.1 KΩ
If normal, proceed to b.
Faulty: Replace the changeover solenoid (SV1).
b. Measure the voltage at the changeover solenoid
(SV1) yellow ~ black wires.
Normal: 80 ~ 100 VDC
If normal, proceed to check item 3, on next
page.
Faulty: Replace the PCB unit.

REU-2532W Series

Rinnai

3) Is the modulating valve operating normally ? Error code 52
a. # Disconnect the modulating valve festoon C2
terminals and measure the resistance at the
terminals.
Normal: 67 ~ 81 Ω
If normal, check b.
Faulty: Replace modulating valve.
b. Re-connect terminal C2 and measure voltage across
the pink ~ pink wires when the unit is firing.
Normal: 2 ~ 15 VDC
If normal, check c below.
Faulty: Replace the PCB unit.
c. Investigate the change in the manifold gas
pressure, when the remote control pre-set
temperature is altered from 96 ~ 140 ºF.
Normal: If the manifold pressure changes,
proceed to check item 4 below. DO NOT
adjust manifold pressures.
Faulty: Replace modulating valve.

4) Is the water flow servo normal ?
a. # Disconnect connector B2 and measure the
resistance of the water flow servo, red ~ blue
wires.
Normal: 19 ~ 24Ω
If normal, proceed to b.
Faulty: Replace the water flow servo and sensor.
b. Disconnect connector B2 , and measure the
voltage on the PCB unit side, were the orange
(+), and/or grey or black (-) wires connect to the
board.
Normal: 3.3 ~ 4.5 VDC
If normal, proceed to c.
Faulty: Replace the PCB unit.
c. With connector B2 , connected (do not turn water
ON … wait for the water flow servo to return to
fully open), measure the voltage at the brown ~
grey wires.
Normal: 4 ~ 6 VDC vent limiter OFF
Faulty: Replace the water flow servo and
sensor.
d. With connector B2 , connected (do not turn water
ON… wait for the water flow servo to return to fully
open), measure the voltage at the yellow ~ grey
wires.
Normal: Less than 0.5 VDC when unit is set at 120
°F and there is no water flowing through the unit. .
Faulty: Replace water flow servo and sensor.

REU-2532W Series

Rinnai

Anti-frost heaters do not operate
1) Are the ceramic anti-frost heaters OK ?
a. # Disconnect connector F4, and measure the
resistance of the heater mounted in the water
flow control valve, these are white wires.
Disconnect connector F5, and measure the
resistance of the heater in the outlet line
connector See connectors in the first and second
picture to the left.
Normal: 348 ~ 375 Ω
If normal, proceed to b.
Faulty: Replace defective element.

b. # Take an ohm meter and read resistance across the
heater on the face of the heat exchanger. The
resistance across this element is listed below. See
third picture to the left for location of this element.
These are white wires.
Normal: 100 ~ 110Ω
If normal, proceed to check item 2 below.
Faulty: Replace defective anti frost heater
assembly.
c. Check resistance of the two heat exchanger
outlet line heater elements, as shown in the
third picture to the left. Check across each heater
independently.
Normal: 33 ~ 39Ω
Faulty: Replace defective anti frost heater
assembly.

2) Is the frost sensor switch operating normally ?
a. # Disconnect connector F2, and measure the
resistance through this switch, measure when
atmospheric temperature is 39 ºF + or – 3 ºF.
See drawing to left for location of this sensor,
these are blue wires to this switch.
Normal: Less than 1Ω
If normal, check wiring harness for defects.
(100 volts AC)
Faulty: Replace the frost sensing sensor.
# If the atmospheric temperature is too high,
cool the switch with ice.

REU-2532W Series

Rinnai

23.

ELECTRICAL COMPONENT ANALYSIS

Nature of Fault
A. The LED on
the remote
control does not
light up, when
the system is
powered up

Examination Point
1. Do you have
voltage to the unit?

Diagnostic Point
Inspect visually

Values

Y/N

Action

Do you have 120 VAC
at the power supply?

Yes

Go to A – (2)

Plug in cord

Yes
No

Yes

Go to A – (3)
Check power
supply circuit.
Check fuses.
Go to A – (4)

Go to A – (5)

Yes

Go to A – (5)
and replace
fuse.
Go to A – (6)

2. Is supply voltage
correct?

Measure voltage at power
point.

120 VAC

3. Check surge
protector.

Inspect visually

Do you have 120 volts
AC across the blue
and brown wires at the
surge protector?
Is fuse blown.

4. Check 3 amp
electrical fuses.

5. Check for short
circuits.

6. Check to ensure
you have 120 VAC
across both terminals
feeding the surge
protector.

REU-2532W Series

# Disconnect and measure
resistance to confirm if
fuse is blown. Normal <
than 1MΩ

Repair
No

1. Measure resistance of
each solenoid valve.
# Remove connector E
from the PCB before
measuring .
Pink ~ Black (SV0)
1.7 ~ 2.1KΩ
Yellow ~ Black (SV1)
1.7 ~ 2.1KΩ
Brown ~ Black (SV2)
1.7 ~ 2.1KΩ
1. Measure the
resistance.
# Disconnect sparker
connector F8 and measure
the resistance between both
terminals.

Are valves within
those specified at left?
# Measure after
checking that there are
no broken wires or
shorts.

Yes

Go to A – (6) 2

Replace faulty
solenoid
valves.

Is resistance >1MΩ ?

Yes

Go to A (5-3)

Replace
sparker.

3. Check wiring.

Are there any shorts ?

Yes

1. Measure voltage at the
blue and brown or black
and white wires.

100 ~ 120 VAC

No
Yes

Rectify/
Replace
Replace PCB
Go to A (6-2)

5
6

Check for
proper voltage
to unit.

Rinnai

Nature of Fault

Examination Point

Diagnostic Point
2. Measure the
voltage at connector
F with appliance
power supply on.

Values

Y/N

Are valves within
those specified at left.

Yes

Go to A – (7)

Replace
transformer

Yes

Check cable for
shorts or broken
wires. Replace
remote control
Replace PCB.

Yes

Go to B–1-2

Replace PCB

Yes

Go to B - 2

Replace water
flow sensor.

Yes

Replace PCB

Replace flame
rod
Replace water
temperature
thermistor.
Go to B-4

F – Black ~ white
100 ~ 120 VAC
F7 – Blue ~ Brown
100 ~ 120 VAC
7. Check remote(s)
(where connected).

B. Digital monitor
lights up, but
combustion does
not commence.
(When remotes
are connected).

1. Check water flow
sensor.

Error code “72”
displayed on the
digital monitor.

2. Check flame rod

Error code “32”
displayed on
digital monitor.

3. Check outgoing
water temperature
thermistor.

Error code “61”
displayed on
digital monitor

REU-2532W Series

4. Check combustion
fan.

Measure voltage
between remote
control terminals at
D.

11 ~ 13 VDC Digital

Action

1. Measure voltage
between red ~ black
of connector B4.

11 ~ 13 VDC

2. Measure voltage
between yellow ~
black at connector B4.

4 ~ 7 VDC

# Measure resistance
between flame rod
terminal C1 and earth

Resistance > 1MΩ?

# Disconnect
connector B5 and
measure resistance.
Open circuit: > 1MΩ
Short circuit: <1Ω

Are values as shown
at left.

1. Check motor.
Measure voltage
between black ~ red
at connector A1.
2. Check fan rotation
sensor. Measure
voltage between
black ~ yellow at
connector A1..
3. Measure voltage
between black ~
white of connector
A1.

6 ~ 45 VDC (Fan on)

Yes

Go to B–5-2

0 VDC (Fan off)

Replace PCB

11 ~ 13 VDC

Yes

Go to B-4-3

Replace PCB

Yes

Go to B-5

Replace fan

6 ~ 45 VDC

Yes

Repair
No

Rinnai

Nature of Fault
Error code “11”
displayed on
digital monitor.

Examination Point
5. Check sparker.

6. Check main gas
solenoid valve (SV0)
Error code 71

7. Check solenoid
valve (SV1)

8. Check changeover
solenoid valve (SV2)

Error code “14”
displayed on
digital monitor

9. Check thermal fuse

10. Check overheat
(remaining flame) bimetal switch.

REU-2532W Series

Diagnostic Point

Values

Y/N

Action

1. Measure voltage
between grey ~ grey of
connector F8 (sparker)

90 ~ 110 VAC

Yes

Go to B-5-2

Is the resistance >1MΩ

No
Yes

Replace PCB
Go to B-5-3

2. # Remove connector
F8 and measure the
resistance between
sparker terminals.

Replace sparker.

3. Check if unit is
sparking.

Is the sparker
sparking?

Yes

Go to B-6

1. # Disconnect the
main solenoid valve
connector E from the
PCB, and measure
resistance between pink
~ black (SV0)
2. Measure voltage
between pink ~ black of
SV0 connector.
1. # Disconnect
connector E from the
PCB. Measure
resistance between
yellow ~ black (SV1)
2. Measure voltage
between yellow ~ black
of SV1 connector.
1. #Disconnect
connector E from PCB.
And measure resistance
between blue ~ black
(SV2)
2. Measure the voltage
between blue ~ black of
SV2 connector.
1. #Disconnect
connector B3 and C3
measure resistance
between red ~ red
2. #Disconnect OHS
(remaining flame) bimetal switch festoon
terminal B3 and C3 , and
measure resistance
between terminal on
switch.

1.7 ~ 2.1KΩ

Yes

Adjust/replace
electrode.
Go to B-6-2

Replace main
solenoid valve
(SV0)

Yes

Go to B-7

Replace PCB

Yes

Go to B-7-2

Replace (SV1)

Yes

Go to B-8

Replace PCB

Yes

Go to B-8-2

Replace (SV2)

Yes

Go to B9

Replace PCB

Yes

Go to B-10

Replace thermal
fuse
Replace PCB

Replace
remaining flame
bi-metal switch

80 ~ 100 VDC

1.7 ~ 2.1KΩ

80 ~ 100 VDC

1.7 ~ 2.1KΩ

80 ~ 100 VDC

Is resistance <1Ω?

Yes

Repair
No

Rinnai

Nature of Fault
C. Combustion
occurs, but flame
fails.

Examination Point

Y/N

Action

Yes

Go to C-1-2

Replace PCB

Yes

Go to C-2

Replace/rectify

Yes

Check for other
causes of flame
failure.

Replace or repair
grounding circuit
to unit.

5 ~ 150 VAC

2. Check to ensure
flame rod bracket is not
loose.

Is it secure?

Check for faulty ground
wire connections at
unit, receptacle, and
ground rod to home,
and for broken or
shorted wires.

Are connections OK?

1. Check hot water
thermistor.

# Disconnect connector
B5 and measure the
resistance between
white ~ white. See
diagnostic points on
page #34 for
temperature at various
resistance.

Resistance values
match table on page
#44.

Yes

Go to D – 2

Replace water
temperature
thermistor.

2. Check
changeover
solenoid valve
(SV3)

1. # Disconnect
solenoid connector E
from PCB and measure
the resistance between
brown ~ black.
2. Measure voltage
between brown ~ black
wire of the changeover
solenoid valve (SV3) at
connector E.
1. #Disconnect
modulating valve at C2
festoon terminal and
measure resistance at
solenoid terminals.
2. Measure the voltage
between the two
harness terminals at C2.
3. Check whether the
manifold pressure alters
when remote control
temperature is altered
between 96° ~ 140°F.
1. #Measure resistance
between red ~ blue
wires of the water flow
servo connector B2.

1.7 ~ 2.1KΩ

Yes

Go to D-2-2

Replace (SV3)

Yes

Go to D-3

Replace PCB

Yes

Go to D-3-2

Replace
modulating valve

Yes

Go to D-3-3

Replace PCB

Does the manifold
pressure change?

Yes

Go to D-4

Replace
modulating valve
(POV)

22 ~ 26Ω

Yes
No

Go to D-4-2
Replace water
flow servo
sensor.

2. Check ground
wire.

3. Check modulating
valve.

4. Check water flow
servo

REU-2532W Series

Values

1. Measure the voltage
between flame rod
terminal C1 and
appliance ground.

1. Check flame rod

Error code “12”
Displayed on
digital monitor.

D. Cannot adjust
water temperature.

Diagnostic

80 ~ 100VDC

67 ~ 81Ω

2 ~ 15VDC

Repair
No.

Rinnai

Nature of Fault

E. Anti-frost
heater does not
work.

Examination Point

1. Check anti-frost
heater.

2. Check frost
sensing switch.

REU-2532W Series

Diagnostic Point

Values

2. Measure voltage
between orange (+) and
grey (-) of the water
flow servo connectorB2.
3. Measure voltage
between brown ~ grey
of water flow servo
connector B2. (Do not
turn water on).
4. Measure voltage
between yellow ~ grey
of the water flow servo
connector B2. (Do not
turn water on)

11 ~ 13 VDC

4 ~ 6 VDC

1. #Disconnect
connector F3 and F
measure resistance
across each of the
heating elements.
(White wires)

348 ~ 375Ω

2. #Read resistance of
the heating element that
is mounted on the front
of the heat exchanger.
(White wires)

100 ~ 110Ω

3. Read resistance of
heating elements on the
heat exchanger outlet
hot water line.

33 ~ 39Ω

#Disconnect connector
F2.and measure across
the frost sensing relay
located on the bottom
left of the casing. This
is a black plastic piece
with two blue white
connected to it. Check
this switch at
temperatures below
37°F. You can place an
ice cube against the
switch to activate it.

Is resistance <1Ω
after applying ice to
this switch for five
minutes?

Y/N

Action

Repair
No

Yes

Go to 4-3

Replace PCB

Yes

Go to D-4-4

Replace water
flow servo
sensor.

Yes
No

Normal
Replace
flow
sensor.

Yes

Go to E-1-2

Replace Antifrost heater
located in the
water valve.
Go to E-2

Yes
No

water
servo

Replace antifrost heater that
is defective.
Go to E-2
Replace antifrost heater that
is defective.
Check wiring

Replace Antifrost sensing
switch.

Rinnai

Gas Pressure Setting Procedure

CONTINUUM and INTEGRITY
REU-2532- W
All settings/adjustments must be performed
by a qualified Service Technician.
1. Turn unit off at power source and turn off the gas to the water heater.
2. Remove the front cover from the water heater.
3. Remove the gas pressure test port plug. Connect manometer to this port. See Figure #1 for location of the
test port plug. Turn on the gas to the water heater.
4. Flow water through the water heater at the maximum flow rate obtainable, at least three gallons per minute.
5. To adjust the “Low” fire pressure, set combustion control dip switch #7 to the “ON” position, and switch
#8 to the “OFF” position (see figure #2 for location of combustion control switches.) This will put the unit
into forced low fire. Check the pressure reading on your manometer. If the pressure needs adjusting, remove
the rubber plug from the bottom of the water heater casing (located beneath the regulator), to access the
regulator adjustment screw. Adjust the regulator screw to achieve the correct gas pressure. (See figure #1 for
location of the regulator adjustment screw.) Below are the proper pressures for “Low” fire, per gas type.
Propane
Natural

0.88” w.c. @ 10” w.c. supply
0.56” w.c. @ 6” w.c. supply

(Low fire rate of 15,000 BTU’s)
(Low fire rate of 15,000 BTU’s)

6. To adjust the “High” fire pressure, set combustion control dip switch #7 to the “ON” position, and switch
#8 to the “ON” position (see figure #2 for location of the combustion control switches), this will put the unit
into forced high fire. Check the pressure reading on your manometer. If the pressure needs adjusting,
adjust it by turning the high pressure “Pot”. See figure #2 for location of “high pressure setting pot”.
Below are the proper pressures for “High” fire.
Propane
Natural

5.1” w.c. @ 10” w.c. supply
3.4” w.c. @ 6” w.c. supply

(High fire rate of 180,000 BTU’s)
(High fire rate of 180,000 BTU’s)

7. Verify both low and high fire pressures by placing the water heater into “Forced Low Fire” and “Forced
High Fire” as described in steps 5 and 6 above. This completes the gas pressure setting procedure.
Dip switches #7 and #8 (combustion control switches), MUST be returned to the “Off” position, after
setting the pressures.

REU-2532W Series

Rinnai

8. Turn off the gas to the w ater heater. Remove the manometer connection. Reinstall the
pressure port plug. Turn on the gas to the water heater and check for gas leaks around
test port with a leak solution.
9. Reinstall the front cover and place the unit back into operation.
10. Verify you are getting the proper water temperature, as set on the controller at your
outlets. If controllers are not being used the output temperature should be 120°F.

Figure #1

Figure #2

M anifold gas
pressure test port.

High pressure setting “Pot”

Regulator adjustment screw used when
setting low and high fire manifold gas
pressures only. DO NOT, adjust this screw
without following gas pressure setting
procedures.

REU-2532W Series

Dip switches #7 and #8 are used when
adjusting low and high fire manifold
gas pressures, as stated in the gas
pressure setting procedure.

Rinnai

25. Dismantling for Service

NOTE: Before proceeding with dismantling, be sure to follow the CAUTION
instructions before each explanation. Always disconnect the electrical supply, turn off
water and gas supply service valves, and drain all water from the unit before
proceeding. Only trained and qualified service agencies should attempt to repair
this product.
Item

Page

1. Removal of the Front Panel ………………………………………………………………… 55
2. Removal of the PC Board …………………………………………………………………… 55
3. Removal of the Water Flow Control and Sensor ………………………… ……………… 55
4. Removal of the Sparker ……………………………………………………………………... 56
5. Removal of the Combustion Fan …………………………………………………………… 56
6. Removal of the Water Temperature Thermistor …………………………………………

7. Removal of the Transformer ………….……………………………………………………

8. Removal of the Burner and Burner Manifold ……………………………………………

9. Removal of the Gas Valve Assembly………………………………………………………

!0. Removal of the Heat Exchanger Assembly ……..………………………………………… 58
11. Removal of the Thermal Fuse ……………………………………………………………… 59

Re-assembly in all task listed above in the reverse order of dismantling, unless
stated otherwise.

REU-2532W Series

Rinnai

IMPORTANT
When dismantling the unit you should always isolate the
following items.
• Gas supply.
• Electrical supply.
• Water supply.
• Drain all water from the appliance.
The following diagram may be of assistance in locating
the above.

Removal of PC board
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Remove the two (2) screws holding the PCB in
place with a Phillips screw driver, then pull the
PC board out of the appliance.
Disconnect all connectors.

P.C. board
screws

Gas shut-off

Cold and hot water shut-off valves

1. Removal of the Front Panel

3. Removal of the Water Flow Sensor and Water
Flow Control Valve Assembly

CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.

a. Remove the four (4) screws holding the panel in
place with a Phillips driver.

a. Remove one (1) Phillips screw from the heat exchanger
water supply line and (1) screw from the bypass valve
assembly. Lift the water line retainer up and over the
housing it attaches too, pull water line towards yourself
to disconnect water lines from the assembly. Inspect orings for damage, replace if defective.

Front cover screws.

Water flow sensor
and servo assembly

REU-2532W Series

Rinnai

a. Remove the four (4) Phillips screws that secure the
water inlet filter housing to the unit. See picture
below for location of screws. Once screws are
removed reach into the unit and pull up and out on the
flow control assembly to remove it from the
appliance. Inspect o-ring for damage.

5. Removal of the Combustion Fan:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Disconnect wiring harness from fan motor.
b. Remove the (2) Phillips screws that secure the
combustion fan motor to the fan housing. Pull the fan
motor assembly towards yourself to remove it.

Water filter housing.

Remove combustion
fan motor housing,
(2) screws screws.

b. Disconnect wiring harness from assembly and remove
the water flow control assembly from the unit.

4. Removal of Sparker Module:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Remove one (1) Phillips screw that secures the
sparker module to the unit casing.
b. Disconnect high tension lead and connector.

6. Removal of the Water Temperature Thermistor:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Remove the two (2) Phillips screws that secure
the thermistor in place to remove the water outlet
temperature thermistor.

Sparker module.
Outlet water thermistor.

REU-2532W Series

Rinnai

7. Removal of Transformer:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Remove the combustion fan motor assembly as
described in section 5-a,b.
b. Remove the two (2) Phillips screws to release the
transformer.
c. Disconnect wiring harness connectors to transformer
and pull out towards you.

Burner plate screws
(6), and (3) gas valve
assembly screws.

d. To remove the burner assembly remove (8) Phillip
screws around the sight glass panel. Remove this
panel.
e. Locate the (2) Phillip screws inside the burner
chamber that hold the burner assembly in place.
Remove these two screws, grip the burner assembly
and slide it out of the combustion housing.
Transformer and
wiring harnesses.

8. Removal of Burner Manifold and the Burner:
Remove (2) screws shown by
arrows and (8) screws in the
view glass panel above, then
pull burner out toward you.

CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
f.
a. To remove the burner manifold, remove (6) Phillip
screws around the burner plate as shown in the upper
right picture.
b. Remove the (3) Phillip screws at the gas valve
assembly.
c. Grip the burner manifold and remove it from the unit.

If you need to remove each burner from this housing
remove the (2) Phillip screws on each side of the
burner, as shown below.

Burner assembly.

REU-2532W Series

Rinnai

b. Remove the heat exchanger water connection lines,
refer to section 3-a.
c. Remove the three (3) Phillip screws securing the gas
manifold assembly to the gas control valve.
d. Remove the six (6) Phillip screws that secure the heat
exchanger assembly in place.
e. Disconnect connectors B1, B5, B6, C1, C3, F1and F8.
These are the igniter, flame rod, thermo-fuse, hot
water inlet and outlet thermistor, and the anti-freeze
heater connections.

9. Removal of the Gas Valve Assembly:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.
a. Remove the burner manifold, refer to section 8-a,b,c.
b. Remove the four (4) Phillips screws that hold the gas
connection and gas control valve in place at the
bottom of the unit. Pull the gas connection down to
disconnect it from the gas valve assembly. Inspect oring for damage and/or defects. Ensure o-ring is in
place when re-assembling this connection.

Heat exchanger inlet
and outlet water lines

Gas connection

c. Disconnect connectors from solenoids, note which
connector goes to each solenoid, alone with the proper
wire colors. Pull gas valve assembly out of unit.

f. Pull the heat exchanger out of the heater.
g. Transfer all components found on the old heat
exchanger over to the new exchanger.

Gas valve

Remove (4) screws
recessed between casing
and heat exchanger.

10. Removal of Heat Exchanger:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.

Remove (2) screws back
behind combustion fan
motor assembly.

a. Remove PCB unit, refer to section 2-a.

REU-2532W Series

Rinnai

7. Removal of Thermal Fuse:
CAUTION
120 volt potential exposure. Isolate the appliance and
reconfirm power has been disconnected using a multimeter.

a. The REU 2532 has four thermal fuses, see picture
below for location.
b. Disconnect and remove the thermal fuse. Re-install
new thermo fuse using the existing thermo fuse clips.
Reconfirm inlet and manifold gas pressures are set to
the proper setting. Ensure unit matches gas type being
supplied to the heater.

This process may involve removing the heat exchanger if
the thermo-fuse on the rear of the heat exchanger is
blown.

Thermal fuse assembly, one
located on the front of the
heat exchanger and one on
the rear of this assembly.

REU-2532W Series

Rinnai

26.

EXPLODED VIEW - CABINET

REU-2532W Series

Rinnai

EXPLODED VIEW - INTERNALS

REU-2532W Series

Rinnai

EXPLODED VIEW - INTERNALS

REU-2532W Series

Rinnai

EXPLODED VIEW - ELECTRICAL

REU-2532W Series

Rinnai

PARTS LIST
Number

Description

Part Number

Quantity

001

Front Panel Assembly

U245-1110

002

Casing Assembly

U245-1100

003

Wall Installation Bracker

U195-121

004

Connection Reinforcement Panel

U245-120

005

Heat Protection Plate

U245-107

006

Rubber Bushing

CF79-41020-A

007

Front Panel Packing

BU195-167

008

Front Panel Packing Side

AU115-163

009

Cable Connection

BU56-602-N

010

Cable Seal Packing

AU169-126

011

Seal Packing

AU105-113

100

Gas Control Assembly

C36E-41-S

101

Screw

AU39-965

102

“Gas Connection (3/4””NPT)”

CU195-1866

103

Burner Unit Assembly

H73-110

104

Burner Case Front

CH51-209

105

Burner Case Bottom Panel

H73-112

106

Packing

BH51-218

107

Lean and Rich
Bunsen Burner Assembly

B3A7-1

108

Burner Case Back Panel

CH51-211

109

Damper

H73-115

110

Manifold Assembly-A (LPG)

U245-200-A

110

Manifold Assembly-C (Nat. G)

U245-200-C

REU-2532W Series

Rinnai

PARTS LIST
Number

Description

Part Number

Quantity

111

Packing of Combustion Chamber

AU155-207-2

112

Lower Packing of Combustion Chamber

H73-214

113

Screw

C10D-5

114

Combustion Chamber

U245-260

Front Plate Assembly

115

Combustion Chamber Front Plate

U245-261

116

Electrode

H73-120

117

Flame Rod

AH41-216

118

Electrode Packing

AH66-398

119

Electrode Holder

AH66-393

120

Upper Packing of Combustion Chamber

U245-262

122

Fan Casing Assembly

CH51-615

123

Blower Motor

H89-261

127

Fan Connecting Bracket

BH29-606

128

Fan Connecting Packing

AU183-562

132

Combustion Chamber Bracket

U245-255

135

Flue Outlet Assembly

U245-1131

136

Flue Outlet

U245-1130

137

Flue Outlet Packing

U245-1122

138

Flue Outlet Packing - 6

AH24-653-6

140

Heat Exchanger Complete Assembly

U245-1310

400

“Water Inlet (3/4”NPT)

H73-501-2

401

Water Flow Servo & Sensor Assembly

M8E-6-5

402

Rectifier

M8D1-15

REU-2532W Series

Rinnai

PARTS LIST
Number

Description

Part Number

Quantity

403

By-pass Servo Assembly

M6J-1-3

404

Stop Bracket

AH69-310

405

Plug Band

H73-512

406

Water Filter Assembly

H73-511

407

Filter Plug

H73-510

408

Hot Water Outlet (3/4”NPT)

U245-865-3

409

Stop Bracket

AU162-1876

410

Plug Band Small

AU103-413

411

Drain Valve

AU142-444

702

PCB Cover-Side

BU195-507

703

PCB Cover-Front

BU168-707

704

Transformer Assembly

ET-281

705

PCB Bracket

U245-257

706

Ignitor

EI-189

707

High Tension Cord

BH38-710-240

708

Electrode Sleeve

AU206-218

709

Thermistor

BH45-650

710

Thermistor Clip Large

CP-90172

711

Thermal Fuse Clip

U217-676

714

Heater Connecting Harness

U245-621

715

120V Valve Heater Assembly

U245-622

716

Anti-Frost Heater Clip

CF29-752

717

Anti-Frost Heater Clip A

AU111-653

REU-2532W Series

Rinnai

PARTS LIST
Number

Description

Part Number

Quantity

718

Anti-Frost Heater Clip

AU100-721

720

Power Supply Harness

AU195-1876

721

Fuse Harness

BU195-1630

722

100V Harness

U245-601

723

Solenoid Valve Harness

U245-602

725

Thermal Fuse Harness

U245-610

726

Mold-Type Over Heat Switch

BU129-824-2

730

PCB

U245-1200

731

Surge Protector

BU195-1873

732

Frost Sensing Switch

H73-750

733

120V Anti-Frost Heater Assembly

U245-1320

734

Sensor Harness - 2

U245-603-2

802

Washer

AU33-184

803

Screw

CP-21478-412

804

Screw

U217-449

805

Screw

ZAA0408UK

806

Screw

ZBD0508UK

807

Screw

AU48-174

808

Screw

ZBA0510UK

809

Screw

ZAD0408TK

810

O-ring

M10B-2-4

812

O-ring

M10B-13-4

813

O-ring

M10B-2-18

REU-2532W Series

Rinnai

PARTS LIST
Number

Description

Part Number

Quantity

814

O-ring

M10B-2-16

815

O-ring

M10B-2-14

816

O-ring

M10B-2-7

817

O-ring

M10B-1-24

818

Packing

C36E1-6

888

V2532W Owner’s Manual

U245-1360

Package Spec Sheet

PWB-261

“Manual 3/4”” gas control valve”

BU195-1865

Kitchen remote control kit

MC-45-4US

Bathroom remote control kit

BC-45-4US

2nd Bathroom remote control kit

BSC-45-4US

REU-2532W Series

Rinnai

SERVICEMAN’S TROUBLESHOOTING INFORMATION
for the
RINNAI “CONTINUUM REU2532-W” WATER HEATERS
IMPORTANT SAFETY NOTES:
There are a number of (live) tests that are required when fault finding this product. Extreme care
should be used at all times to avoid contact with energized components inside the water heater.
Only trained and qualified service agencies should attempt to repair this product.
Remember, before checking for resistance readings, you should disconnect the power source to
the unit and isolate item the to be checked from the circuit (unplug it).
(TR) Transformer:
Wire color
Black ~ White
Blue ~ Brown

Voltage
100 ~ 120 VAC
110 ~ 120 VAC

Resistance
51 ~ 63 ohms
51 ~ 63 ohms

Connector #
F9
F7

(SV0, SV1, SV2, SV3 and POV) Gas valve and Modulating solenoids: (Set meter above 2K)
(SV0) Pink ~ Black
80 ~ 100 VDC
1,8K ~ 2K ohms
E1
(SV1) Black ~ Yellow
80 ~ 100 VDC
1,8K ~ 2K ohms
E2
(SV2) Black ~ Blue
80 ~ 100 VDC
1,8K ~ 2K ohms
E3
(SV3) Black ~ Brown
80 ~ 100 VDC
1,8K ~ 2K ohms
E4
(POV) Pink ~ Pink
2 ~ 15 VDC
67 ~ 81 ohms
C2

Pin #’s
1~2
1~3

1~2
2~3
2~4
2~5
3~4

(M) Water Flow Control Device Servo or Geared Motor:
Red ~ Blue
11 ~ 13 VDC
22 ~ 26 ohms
B2
9 ~ 10
Grey ~ Brown
4 ~ 6 VDC
N/A
B2
5~7
Grey ~ Yellow
B2
5~8
N/A
N/A
Grey ~ Orange
11 ~ 14 VDC
N/A
B2
5~6
NOTE: The grey wire listed above turns to black at B connector on the PCB, the orange wire turns to red.
(QS) Water Flow Sensor:
Black ~ Red
11 ~13 VDC
Yellow ~ Black
4 ~ 7 VDC
By-pass Flow Control:
Brown ~ White
Orange ~ White
Yellow ~ White
Red ~ White/ Ground
(IG) Ignition System:
Grey ~ Grey

2 ~ 6 VDC

90 ~ 100 VAC

(FM) Combustion Fan Motor:
Red ~ Black
6 ~ 45 VDC
REU-2532W Series

5.5K ~ 6.2K
1 meg ~ 1.4 meg

B4
B4

5~6
1~5

Unit in operating
mode
15 ~ 35K

G4 ~ G5
G2 ~ G5
G1 ~ G5
G3 ~ G5

4~5
2~5
1~5
3~5

N/A

2~3

N/A

1~2

Rinnai

White ~ Black
6 ~ 45 VDC
9.2K ~ 9.4K
A1
2~4
Yellow ~ Black
11 ~ 13 VDC
3.5K ~ 3.9K
A1
2~3
Set your meter to the hertz scale. Reading across the red and yellow wires at terminals 2 and 3 you should
read between 60 and 350 hertz.
Thermal Fuse:
Red ~ Red
100 VAC
Below 1 ohm
B~C
B6 ~ C1

Overheat Switch:
Red ~ Red

100 VAC

Below 1 ohm

B~C

B6 ~ C1

Flame Rod:
Place one lead of your meter to the flame rod and the other to earth or ground. With the unit running you should read
between 5 ~ 150 VAC. Set your meter to the µ amp scale, series your meter in line with the flame rod. You should read
1µ or greater for proper flame circuit. In the event of low flame circuit remove the flame rod and check for carbon and/or
damage.
Heat Exchanger, Air Temperature, and Outgoing Water Temperature Thermistors:
Check all thermistors by inserting meter leads into each end of the thermistor plug. Set your meter to the 20K
scale and read resistance. You should be able to apply heat to the thermistor bulb and see the resistance
decrease. Then apply some ice to the thermistor and the resistance should increase. See below for examples
of temperatures and resistance reading at those temperatures.
Example: 59ºF = 11.4 ~ 14K
86ºF = 6.4 ~
113ºF = 3.6 ~
140ºF = 2.2 ~
221ºF = 0.6 ~

7.8K
4.5K
2.7K
0.8K

Outgoing Water Thermistor:
White ~ White
N/A

See example above

B3 ~ B4

Heat Exchanger Temperature Thermistor:
White ~ Pink at board
N/A

See example above

B3 ~ B12

Surge Protector:
Black ~ White
108 ~ 132 VAC
N/A
Surge Protector D1
1~3
Blue ~ Brown
108 ~ 132 VAC
N/A
Surge Protector D2
1~2
With the power off you can check the continuity through the surge protector. Place one meter lead on the top pin #1 of the
surge protector and pin #2 on the bottom of the surge protector. Then check across top pin #3 and bottom pin #1, if you
read continuity across these two points the surge protector is good. If you do not get continuity, replace the surge protector.
Remote Controls:
Terminals D1

10 ~ 13 VDC digital

1.5K ~ 1.9K ohms

1~3

Frost Protection:
This unit has four frost protection heaters mounted at different points inside the unit, to protect the water
heater from freeze ups. There are two heaters located on the outlet hot water line next to the thermistor.
REU-2532W Series

Rinnai

Using a voltage meter set on the 200 ohm scale, you should have a resistance reading of 26 ~ 30 ohms
through each of these heaters. The heater located on the heat exchanger piping should have a resistance
reading of 81 ~ 86 ohms and the one located in the water flow sensor valve has a resistance reading of 16 ~
19 ohms. Voltage throughout this circuit should be 120 VAC.

(3) Amp Fuses:
This unit has two inline (3) amp glass fuses. Remove the fuse and check continuity through it. If you have
Continuity through the fuse, it is good. If you can not read continuity, the fuse is blown and must be replaced.

Wiring Diagram:
REU2532-W

REU-2532W Series

Rinnai

sk about Rinnai’s other fine products:
The Silent Servant
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The Energy Savers
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The Infra-reds
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Portable Cooking Products
*One, two and two burner with
broiler models.
*Perfect for camping, a picnic or a
tailgate party

www.rinnai.us

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Title                           : REU-2532-W Service Manual 08-08-03.pmd
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REU 2532 W Service Manual 08 03.pmd Rinnai

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