LENNOX Air Conditioner/heat Pump(outside Unit) Manual L0806497

User Manual: LENNOX LENNOX Air conditioner/heat pump(outside unit) Manual LENNOX Air conditioner/heat pump(outside unit) Owner's Manual, LENNOX Air conditioner/heat pump(outside unit) installation guides

Open the PDF directly: View PDF .
Page Count: 24

Download
Open PDF In Browser	View PDF

INSTALLATION
INSTRUCTIONS

'1_2006 Lennox Industries Jnc,
Dallas, Texas, USA

HPXA16 Series Units
HEAT PUMP
504,954M

_Technical

UNITS

LLJJ

08/06

Publications

Litho U.S.A.

Supersedes 03/06

RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE

_, WARNING

CAUTION

A IMPORTANT

_, IMPORTANT

HPXA16 Outdoor Unit ..........................
Shipping & Packing List ........................
General Information ...........................
Unit Dimensions ...............................
Parts Arrangement ............................
Setting the Unit ...............................
Electrical .....................................
Refrigerant Piping .............................
Refrigerant Metering Device ....................
Flushing Existing Line Set & Indoor Coil ..........
Manifold Gauge Set ...........................
Service Valves ................................
Leak Testing ..................................
Evacuation ...................................
Start-Up ......................................
Refrigerant Charging ..........................
System Operation .............................
Defrost System ...............................
Maintenance ..................................
Optional Accessories ..........................
Check Points .................................

1
2
2
2
3
3
4
6
8
8
10
10
11
12
12
12
15
16
21
21
22

Homeowner Information:
Maintenance ..................................
Thermostat Operation ..........................

23
24

Lennox HPXA16 outdoor units use HFC-410A refrigerant.
This unit must be installed with a matching indoor coil and
line set as outlined in the Lennox Engineering Handbook.
Elite ® Series HPXA16 outdoor units are designed for use
in check expansion valve (CTXV) systems only and must
not be used with other refrigerant flow control devices,
See Lennox Engineering Handbook list of indoor expansion valve kits (ordered separately).

08/06

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

Page 1

504,954M

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

Check unit for shipping damage, Consult last carrier immediately if damage is found,
1 -Assembled HPXA16 outdoor unit

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
who have jurisdiction before installation,

WARNING

2 - Grommets (for liquid and vapor lines)

When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened, Table 1 shows
torque values for fasteners.
Table 1
Torque

Requirements

Part

Recommended

Torque

Service valve cap

8 ft.- lb.

11 NM

Sheet metal screws

16 in.- lb.

2 NM

Machine screws #10

28 in.- lb.

3 NM

Compressor bolts

90 in.- lb.

10 NM

Gauge port seal cap

8 ft.- lb.

11 NM

INLET AIR
Model

HPXA16-024,-036

30-7/8 (784)

12-3/4 (324)

17-1/4 (438)

HPXA16-048,

44-7/8 (1140)

14-1/4 (362

18-3/4 (476)

-060

COMPRESSOR

INLET AIR

Top View
ELECTRICAL
32-1/8 (816)

i_
i

VAPOR
LINE INLET'-_

(114)
4-1/2

C J_

2-_/16

2
(51)

LIQUID
LINE INLET

Page 2
504954M

08/06

1-3/6
(35)

INLET
AIR

Coil drain outlets (around
perimeter of base)

RUN CAPACITOR
START CAPACITOR
(-024 UNIT ONLY)

CHARGE

COMPENSATOR
(-048 UNITS)

TXV/CHECK VALVE
DISCHARGE

LINE
CONTACTOR

COMPRESSOR

TERMINAL PLUG
VAPOR VALVE AND GAUGE
PORT

VAPOR LINE
LOW PRESSURE

TWO-STAGE

SWITCH

DRIER

DISCHARGE TEMPERATURE
SENSOR
HIGH PRESSURE

COMPRESSOR

SWITCH

Figure

1
Installation

CAUTION

Clearances

as noted

These units operate under a wide range of weather conditions; therefore, several factors must be considered when
positioning the outdoor unit. The unit must be positioned to
give adequate clearances for sufficient airflow and servicing. Refer to figure 2 for installation clearances.
1. Place a sound-absorbing material, such as Isomode,
under the unit if it will be installed in a location or position that will transmit sound or vibration to the living
area or adjacent buildings.
2. Mount unit high enough above ground or roof to allow
adequate drainage of defrost water and prevent ice
build-up.

(762 mm)
,,11- 30" _

not_

as noted

NOTE - A service access clearance of 30" (762 mm) must be maintained in front of the service access panel. Clearance to one side must
be 36" (914 mm), Clearance to one of the remaining two sides may be
12" (305 mm) and the final side may be 6" (152 ram).
NOTE -A clearance of 24" (610 mm) must be maintained between
two units.

3. In heavy snow areas, do not locate unit where drifting
will occur. The unit base should be elevated above the
depth of average snows.
NOTE -Elevation of the unit may be accomplished by
constructing a frame using suitable materials. If a support frame is constructed, it must not block drain holes
in unit base.

NOTE -48" (1219 mm) clearance required on top
of unit. Maximum soffit overhang is 36" (914 mm).

Figure 2
4. When installed in areas where low ambient temperatures exist, locate unit so winter prevailing winds do
not blow directly into outdoor coil.
5. Locate unit away from overhanging roof lines which
would allow water or ice to drop on, or in front of, coil
or into unit.

Page 3
HPXA16

SERIES

Slab Mounting
When installing unit at grade level, top of slab should be
high enough above the grade so that water from higher
ground will not collect around unit, See figure 3. Slab
should have a slope tolerance away from the building of 2
degrees or 2 inches per 5 feet (51 mm per 1,5 m), This will
prevent ice build-up under unit during a defrost cycle. Refer to roof mounting section for barrier construction if unit
must face prevailing winter winds.

Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.

_WARNING

Slab Mounting
discharge

structure
building

air

2 DEGREES OR
2 IN. PER 5 FOOT
(51 MM PER 1.5 M)
SLOPE
TOLERANCE
AWAY FROM
BUILDING
STRUCTURE

ground

mounting
slab

level

Figure

Install line voltage power supply to unit from a properly
sized disconnect switch,
2, Ground unit at unit disconnect switch or to an earth
ground,
NOTE - Connect conduit to the unit using a proper
conduit fitting. Units are approved for use only with
copper conductors, Refer to figure 5 for high voltage
field wiring diagram, A complete unit wiring diagram is
located on the back side of the unit's access panel.
.

Roof Mounting
Install the unit a minimum of 6 inches (152 mm) above the
roof surface to avoid ice build-up around the unit. Locate
the unit above a load bearing wall or area of the roof that
can adequately support the unit. Consult local codes for
rooftop applications.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed. See figure 4.
Size barrier at least the same height and width as outdoor
unit, Mount barrier 24 inches (610 mm) from the sides of
the unit in the direction of prevailing winds.

Typical
START

Field Wiring

CAPACITOR
C7

POTENTIAL

Diagram
AI08

RELAY

KSI

OUTDOOR
FAN

GROUND

DEFROST
r_

CONTROL

6[_

LUG
K195
SOLENOID

TRANSFORMER

GND

RELA_

ORANGE-COMMON
BLACK-RUN
PURPLE-CAPACITOR

C_8

ILl

DUAL
CAPACITOR

Rooftop

Wind

Barrier

Construction

prevailing winter
winds
wind barrier
I
inlet air

_Lmm/

3rotection

size

Figure

NOTE - For proper voltages, select thermostat wire
gauge per the following chart:
O

I
I

inlet air

Wire run length

AWG #

Insulation type

less than 100' (30m)

color-coded, temperature

more than 100' (30m)

rating 35°C minimum

,J
.

Figure

inlet air

In the U,S.A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC).
Page 4
08/06

60/1

NOTE - For use with copper conductors only. Refer to unit rating
alate for minimum circuit ampacity and maximum over-current

(21'0

504954M

230/

CONTACTOR

WARNING! - ELECTRIC SHOCK HAZARD. Can cause INJURY or
DEATH. Unit must be grounded in accordance with national and local
codes.

208KI
COMPRESSOR

Install room thermostat (ordered separately) on an inside wall approximately in the center d the conditioned
area and 5 feet (1.5 m) from the floor. It should not be
installed on an outside wall or where it can be effected
by sunlight, drafts or vibrations,
Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit, See figures 6
through 8.
NOTE - 24V, Class II circuit connections are made in
the low voltage junction box.

HPXA16 Outdoor
Thermostat

Unit and Blower
Designations

HPXA16

Unit

]

Thermostat

A2 Thermostat

Indoor Unit TB1 I

®
I
I

Unit and CB31MV/CB32MV
Designations

(Some connections may not apply. Refer to specific thermostat
and indoor unit.)
r
i
CB31MV/
I
Signature_at
q
Outdoor Unit
//
CBX32MV TB1
A2 Thermostat

(Some connections may not apply. Refer to specific thermostat
and indoor unit
Outdoor Unit

Outdoor

_---

_ L_I_
i

I
I

_..

®--i

@
®

(_) [ 1R4
T"

q--I-',Board
, Defrost
Y2

I 'Board

-iJ--i--_li-I

I:
i
I,

:out

L .....

--t

Y2
OUT

_ _

- +---®-

_ )

--,_,--_DENOTES
--

SW[TCH_

Wiring

Diagram

$87 LDW
PRESSURE
SWITCH

OPTIONAL

LI
REVERSING
VALVE

RTE3
AMBIENT
SENSOR

NOTEFOR USE WITH COPPER
CONDUCTORS
ONLY.REFER
TO UNIT RATING PLATE FOR MINIMUM CIRCUIT
AMPACITY AND MAXIMUM OVERCURRENT PROTECTION SIZE

REFER TO COMPRESSOR IN UNIT
FOR ACTUAL TERMINAL
ARRANGEMENT,

WARNINGELECTRIC
SHOCK HAZARD,CAN
CAUSE
INJURY
OR DEATH,UNIT
MUST BE GROUNDED
IN
ACCORDANCE
WITH NATIONAL
AND LOCAL CODES•

A
A
A
A
A

REMOVE

COMPONENTS

LINE VOLTAGE FIELD
INSTALLED
CLASS
II VOLTAGE FIELD
INSTALLED

_L_

RT21
DEFROST
CDIL
SENSOR

Figure 7
HPXA16

BI
COMPRESSOR

@f
@

$4
Z_

@.L

-i

HIGH
PRESSURE

I,
i_

Figure

I [Defrost,

i
i

- v- -•
If

RT28
OISCHARGE
SENSOR

RTi4

COIL

FAN

FOR

TWO

K31

AND

SII

AND

KSB

ARE
ARE

STAGE

TEMP

USED

COOL

IOPTIONAL)

024

OPTIONAL

UNITS

LOW

L3¢,SECOND
STAGE,
SOLENOID
COMPRESSOR, COIL IS 24VOC,
24VAC
T_OY_IU
TER_[N_.

z_K5B-I
z_Y2

BLAC_I

JUMPER

SENSOR,OUTDOOR

OUT NOTUSEDIN

ONLY

AMBIENT

HARMONYIIIZONE

CON_ OL APPLICATIONS
SIGNATURE
81MBB

CB31MV
CBX32MV
TBI

AIO8

CONTROLS

IS LOCATED IN
DO NOT CONNECT

A2
THERMOSTAT

49
_MB
@
-(z)OIS

®®

I
I

II
FT
II
II
II
II
II
II

s©
24v

HI-PS

'©

{

Figure

LO-PS

__YI OUT

9 IRT,A

I
I

-_):>-IQ-I--4_-I-

, _
Y2 OUT _-_

DEFROST
BOARD
DETAIL

-- 0

°_

- c_

BLUE WIRE
WITH

m _1

CRIMPED

TERM,NAL

I 111

_'/'_lil
_

_'_-_-_

Shipped
as shown
wire;
cut off terminal
and above
splice with
blue terminal
wire withcrimped
Y2 wire totoblue
indoor
unit.use terminal

Page 5
HPXA16

SERIES

1, Placement--Be aware some localities are adopting
sound ordinances based on how noisy the unit is at the
neighbors' home, not at the original installation. Install
the unit as far as possible from the property line, When
possible, do not install the unit directly outside a bedroom window, Glass has a very high level of sound
transmission, Figure 9 shows how to place the outdoor
unit and line set,

If the HPXA16 unit is being installed with a new indoor coil
and line set, the refrigerant connections should be made
as outlined in this section. If an existing line set and/or indoor coil is going to be used to complete the HPXA16 system, refer to the following section which includes flushing
procedures.
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections). Use Lennox L15 (sweat, nonflare) series line sets as shown in table 2 or use field-fabricated refrigerant lines. Valve sizes are also listed in table 2.
Refrigerant
Connections
- HPXA16
with New Indoor Coil and Line Set

Outside

Unit Placement

and Installation

Matched

If an existing indoor coil which was equipped with an RFCl
metering device is being replaced, the liquid line must also
be replaced prior to the installation of the HPXA16 unit.
Table 2
Refrigerant
Line Sets
Field
Connections
Recommended
Model
-024
-036
-048
-060

Liquid
Line
3/8in.

Vapor
Line
7/8 in

(10 mm)
3/8 in,
(10 mm)

Line Set

Liquid
Line

Vapor
Line

L15
Line Sets

(22 mm)

3/8 in,
(10ram)

7/8 in
(22ram)

L15-65
15ft,-50ft,
(4.6 m - 15 m)

1-1/8 in.
(29 mm)

3/8 in,
(10 ram)

1-1/8 in,
(29 ram)

Field
Fabricated

Two 90 ° elbows installed in line set
will reduce line set vibration,

NOTE - Units are designed for fine sets of up to fifty feet
(15m),

Figure 9

Installing
Refrigerant
Line
Pay close attention to line set isolation during installation of
any heat pump or a/c system. When properly isolated from
building structures (walls, ceilings, floors), the refrigerant
lines will not create unnecessary vibration and subsequent
noises. Also, consider the following when placing and
installing a high-efficiency outdoor unit:
Refrigerant

Line Sets:

2. Line Set Isolation--The
following illustrations demonstrate procedures which ensure proper refrigerant
line set isolation, Figure 10 shows how to make a transition from horizontal to vertical. Figure 11 shows how
to install line sets on vertical runs. Figure 12 shows
how to install line sets on horizontal runs,

Transition

From

ANCHORED
HEAVY NYLON
WIRE TIE

Vertical

To Horizontal

AUTOMOTIVE
MUFFLER-_PE
HANGER

WALL
STUD

WALL
STUD
Strap Liquid
Line To Vapor Line

Strap Liquid Line
To Vapor Line

UID LINE
METAL
SLEEVE

LIQUID LINE

VAPOR LINE - WRAPPED
IN ARMAFLEX

METAL
SLEEVE

Figure

Page 6
504954M

08/06

VAPOR LINE - WRAPPED
IN ARMAFLEX

Refrigerant
Line Sets: Installing Vertical Runs (new construction
shown)
NOTE - Similar installation practices should be used if line set is to be installed on exterior of outside wall.
OUTSIDE WALL

IMPORTANT - Refrigerant
lines must not contact wall.

VAPOR LINE

-_.

UID LINE

WIRE TIE
INSIDE WALL

- STRAP
SLEEVE
VAPOR LINE WRAPPED
"_-

WIRE TIE

"_ ----------WOOD

IMPORTANT!
Refrigerant
lines must
not contact
structure.

BLOCK

WIRE TIE
STRAP

1_
PVC PIPE

CAULK
FIBERGLASS
INSULATION
SLEEVE

Figure 11
Refrigerant

Line Sets: Installing

To hang line set from joist or rafter,
use either metal strapping material
or anchored heavy nylon wire ties.

Runs

WIRE TIE
8 feet

STRAPPING

Horizontal

(Around vapor line only)

MATERIAL

(Around vapor line only)

FLOOR
JOIST OR
ROOF RAFTER
r\

TAPE OR
WIRE TIE

8 feet

METAL
SLEEVE

FLOOR JOIST OR
ROOF RAFTER

TAPE OR WIRE TIE

Strap the vapor line to the joist or
rafter at 8 ft. intervals then strap
the liquid line to the vapor line.

_rl

Figure

Page 7
HPXA16

SERIES

Isolation

Grommets

Locate the provided isolation grommets. Use a knife to slit
the webbing on each grommet. Slide larger grommet onto
vapor line and smaller grommet onto liquid line. Insert
grommets into mullion to isolate refrigerant lines from
sheet metal edges,

Device Installation

O-RING

_-_%

EXPANSION
/O-RING

/ °

WARNING

Metering

_ o

DISTRIBUTOR

A, IMPORTANT

NOTE -If the indoor unit line and set are new, skip this section and go on to the Manifold Gauge Set section.

_WARNING

4, Quench the joint with water or a wet cloth to prevent
heat damage to the valve core and opening port,
NOTE - The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, sealing and rigidity.

HPXA16 units may be used in check expansion valve
(CTXV) systems only, See indoor coil installation instructions and the Lennox engineering handbook for approved
HFC-410A TXV match-ups and application information,
NOTE - HFC-410A systems will not operate properly with
an HCFC-22 valve.
Check Expansion Valve Systems
Check expansion valves equipped with either Chatleff or
flare-type fittings are available from Lennox. Refer to the
Engineering Handbook forapplicable expansion valves for
use with specific match-ups.
If you install a check expansion valve with an indoor coil
that includes a fixed orifice, remove the orifice before the
check expansion valve is installed. See figure 13 for installation of the check expansion valve.

Page 8
504954M

0_06

LITQuU;D
LINE

NOTE - Ifnecessary,remove HCFC-22 flowcontrol
device (fixed
orifice/check
expansionvalve)from existing
linesetbeforeinstalling
HFC-410A approved expansionvalveand o-ring.

Brazing Connection
Procedure
1, The end of the refrigerant line must be cut square and
its internal shape must remain round. The line must be
free of nicks or dents and must be deburred (I,D, and
O.D,)

3, Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper4o-copper brazing or 45 percent
silver alloy for copper-to-brass
or coppeFto-steel
brazing). Wrap a wet cloth around the valve body and
the copper tube stub. Remove light maroon washers
from service valves and shield light maroon stickers in
order to protect them during brazing, Braze the line set
to the service valve,

(See NOTE)

STRA,
NER

Figure

2, Before making line set connections, use dry nitrogen
to purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the system.

VALVE &

A IMPORTANT

If the existing outdoor unit is equipped with
manual shut-off valves AND you plan to use NEW
HCFC-22 refrigerant to flush the system • Start the existing HCFC-22 system in the cooling
mode and close the liquid line valve.
• Pump all of the existing HCFC-22 refrigerant back
into the outdoor unit. (It may be necessary to bypass the low pressure switches to ensure complete refrigerant evacuation.)
• When the low side system pressures reach 0 psig,
close the vapor line valve.
• Disconnect all power to the existing outdoor unit.
Check gauges after shutdown to confirm that the
valves are not allowing refrigerant to flow back into
the low side of the system.
• Disconnect the liquid and vapor lines from the existing outdoor unit.
2. Remove the existing outdoor unit. Set the new
HFC-410A unit and follow the brazing connection procedure (see page 8) to make line set connections.
DO NOT install metering device at this time.

IMPORTANT

CAUTION

Required Equipment
You will need the following equipment in order to flush the
existing line set and indoor coil: two clean HCFC-22 recovery bottles, an oilless recovery machine with a pump down
feature, and two sets of gauges (one for use with HCFC-22
and one for use with the HFC-410A).

3. Make low voltage and line voltage connections to the
new outdoor unit. DO NOT turn on power to the unit
or open the outdoor unit service valves at this
time.

Flushing
Procedure
1. Remove existing HCFC-22 refrigerant using the appropriate procedure below.
If the existing outdoor unit is not equipped with
shut-off valves, or if the unit is not operational
AND you plan to use the existing HCFC-22 refrigerant to flush the system • Disconnect all power to the existing outdoor unit.
• Connect to the existing unit, a clean recovery cylinder and the recovery machine according to the
instructions provided with the recovery machine.
• Remove all HCFC-22 refrigerant from the existing
system. Check gauges after shutdown to confirm
that the entire system is completely void of refrigerant.
• Disconnect the liquid and vapor lines from the existing outdoor unit.

IMPORTANT

4. Remove the existing refrigerant flow control orifice or
thermal expansion/check valve before continuing with
flushing procedures. The existing devices are not approved for use with HFC-410A refrigerant and may
prevent proper flushing, Use a field-provided fitting to
reconnect the lines.

Flushing

Connections

Inverted HCFC-22 Cylinder
(Contains clean
HCFC-22 to be used for
flushing)

Low
Pressure

EXISTING VAPOR LINE
EXISTING

LIQUID LINE

VAPOR LINE
SERVICE VALVE
LIQUID LINE
SERVICE VALVE

NOTE - The inverted HCFC-22 cylinder must contain at least the
same amount of refrigerant as was
recovered from the existing system.

Tank
Inlet Return
Discharge

RECOVERY

CYLINDER

High
Pressure

RECOVERY

MACHINE

Figure

Page 9
HPXA16

SERIES

5, Remove the pressure tap valve cores from the
HPXA16 unit's service valves. Connect an HCFC-22
cylinder with clean refrigerant to the vapor service
valve, Connect the HCFC-22 gauge set to the liquid
line valve and connect a recovery machine with an
empty recovery tank to the gauge set.

Front-Seated

(Valve Shown Closed)

Line Service

Valve

SERVICE

Insert hex wrench here

6, Set the recovery machine for liquid recovery and start
the recovery machine, Open the gauge set valves to
allow the recovery machine to pull a vacuum on the existing system line set and indoor coil.
7, Invert the cylinder of clean HCFC-22 and open its
valve to allow liquid refrigerant to flow into the system
through the vapor line valve. Allow the refrigerant to
pass from the cylinder and through the line set and the
indoor coil before it enters the recovery machine,
8, After all of the liquid refrigerant has been recovered,
switch the recovery machine to vapor recovery so that
all of the HCFC-22 vapor is recovered,

Liquid

STEM
CAP

To
indoor coil

To outdoor coil

(Valve Shown Open)
insert hex wrench here

NOTE - A single system flush should remove all of the
mineral oil from the existing refrigerant lines and indoor coil. A second flushing may be done (using clean
refrigerant) if insufficient amounts of mineral oil were
removed during the first flush, Each time the system
is flushed, you must allow the recovery machine
to pull a vacuum on the system at the end of the
procedure.
9, Close the valve on the inverted HCFC-22 drum and
the gauge set valves. Pump the remaining refrigerant
out of the recovery machine and turn the machine off.
10, Use dry nitrogen to break the vacuum on the refrigerant lines and indoor coil before removing the recovery
machine, gauges and HCFC-22 refrigerant drum. Reinstall pressure tap valve cores into HPXA16 service
valves.

SERVICE
PORT

STEM
CAP
To
indoor coil
Service port Is open to
line set when valve is
To outdoor coil

closed (front seated)

Figure

Bali-Type

Vapor Valve

(Valve

Closed)

STEM
CAP

11. Install the provided check expansion valve (approved
for use with HFC-410A refrigerant) in the liquid line at
the indoor coil,

OUTDOOR
USE ADJUSTABLE
TO OPEN:
TO CLOSE:

WRENCH

ROTATE STEM

_..

STEM
(STEM

._L_I:,_

ROTATE STEM

CLOCKWIS_
COUNTER-CLOCKWISE

90 °.

BALL (SHOWN

,NDOOR
COIL

SCHRADER

VALVE
SERVICE
PORT CAP

Each valve is equipped with a service port which has a factory-installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.

Page 10
08/06

COIL

_._---,_

Figure

504954M

CLOSEO

Manifold gauge sets used with systems charged with
HFC-410A refrigerant must be capable of handling the
higher system operating pressures. The gauges should be
rated for use with pressures of 0 - 800 on the high side and
a low side of 30" vacuum to 250 psi with dampened speed
to 500 psi. Gauge hoses must be rated for use at up to 800
psi of pressure with a 4000 psi burst rating,

The liquid line and vapor line service valves (figures 15 and
16) and gauge ports are used for leak testing, evacuating,
charging, and checking charge. See table for torque requirements.

, WARNING

IMPORTANT

To Access

Schrader

Port:

1. Remove service port cap with an adjustable wrench,
2. Connect gauge to the service port.
3, When testing is completed, replace service port cap. Replace the stem cap. Tighten finger tight; then torque per
table 1 (Page 2),
To Open

Front-Seated

Service

,&WARNING

Valves:

1. Remove stem cap with an adjustable wrench,
2. Use a service wrench with a hex-head extension
(3/16" for liquid-line valve sizes; 5/16" for vapor-line
valve sizes) to back the stem out counterclockwise as
far as it will go,
3. Replace the stem cap, Tighten finger tight; then torque
per table 1 (Page 2),
To Close

Front-Seated

Service

Valves:

1. Remove the stem cap with an adjustable wrench,
2. Use a service wrench with a hex-head extension
(3/16" for liquid-line valve sizes; 5/16" for vapor-line
valve sizes) to turn the stem clockwise to seat the
valve. Tighten it firmly,
3, Replace the stem cap, Tighten finger tight; then torque
per table 1 (Page 2),
Bali-Type Service Valve (Vapor Line)
Ball-type service valves function the same way as the other valves; the difference is in the construction, These
valves are not rebuildable, If a valve has failed, you must
replace it. A ball valve is illustrated in figure 16,
The ball valve is equipped with a service port with a factoryinstalled Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leakfree seal,

After the line set has been connected to the indoor and outdoor units, the line set connections and indoor unit must be
checked for leaks,

Xk WARNING

Using an Electronic Leak Detector
1. Connect a cylinder of HFC-410A to the center port of
the manifold gauge set.
2, With both manifold valves closed, open the valve on
the HFC-410A cylinder (vapor only),
3, Open the high pressure side of the manifold to allow
the HFC-410A into the line set and indoor unit, Weigh
in a trace amount of HFC-410A, [A trace amount is a
maximum of 2 ounces (57 g) or 3 pounds (31 kPa)
pressure,] Close the valve on the HFC-410A cylinder
and the valve on the high pressure side of the manifold
gauge set, Disconnect the HFC-410A cylinder.
4, Connect a cylinder of dry nitrogen with a pressure regulating valve to the center port of the manifold gauge
set.
5, Connect the manifold gauge set high pressure hose to
the vapor valve service port. (Normally, the high pressure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the manifold gauge set from high pressure damage.)
6, Adjust the dry nitrogen pressure to 150 psig (1034
kPa). Open the valve on the high side of the manifold
gauge set which will pressurize line set and indoor unit.
7, After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge dry nitrogen and
HFC-410A mixture. Correct any leaks and recheck,

,& IMPORTANT

Page 11
HPXA16

SERIES

gauge valves to release the dry nitrogen from the line
set and indoor unit.
Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper piping and compressor parts,

A, IMPORTANT

Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not
rise above 500 microns (29.9 inches of mercury) within
a 20-minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
When the absolute pressure requirement above has
been met, disconnect the manifold hose from the vacuum pump and connect it to an upright cylinder of
HFC-410A refrigerant. Open the manifold gauge
valves to break the vacuum from 1 to 2 psig positive
pressure in the line set and indoor unit, Close manifold
gauge valves and shut off the HFC-410A cylinder and
remove the manifold gauge set,

1, Connect manifold gauge set to the service valve ports
as follows:
• low pressure gauge to vapor line service valve
• high pressure gauge to liquid line service valve
2. Connect micron gauge.

A, IMPORTANT

3. Connect the vacuum pump (with vacuum gauge) to
the center port of the manifold gauge set,
4, Open both manifold valves; start the vacuum pump.
5, Evacuate the line set and indoor unit to an absolute
pressure of 23,000 microns (29,01 inches of mercury). During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once to
determine if there is a rapid rise in absolute pressure,
A rapid rise in pressure indicates a relatively large
leak, If this occurs, repeat the leak testing procedure,

1, Rotate fan to check for frozen bearings or binding,
2, Inspect all factory- and field-installed wiring for loose
connections.
3, After evacuation is complete, open the liquid line and
vapor line service valves (counterclockwise) to release refrigerant charge (contained in outdoor unit)
into the system,
4, Replace stem caps and secure finger tight, then tighten an additional (1/6) one-sixth of a turn,
5, Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit
nameplate. If not, do not start the equipment until the
power company has been consulted and the voltage
condition has been corrected.

NOTE - The term absolute pressure means the total
actual pressure within a given volume or system,
above the absolute zero of pressure, Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure,
6, When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a dry nitrogen
cylinder with pressure regulator set to 150 psig (1034
kPa) and purge the hose. Open the manifold gauge
valves to break the vacuum in the line set and indoor
unit, Close the manifold gauge valves,

6, Set the thermostat for a cooling demand. Turn on power to indoor blower unit and close the outdoor unit disconnect to start the unit,
7, Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.

WARNING

7, Shut off the dry nitrogen cylinder and remove the manifold gauge hose from the cylinder, Open the manifold

This system is charged with HFC-410A refrigerant which
operates at much higher pressures than HCFC-22. The
field-provided check expansion valve for the indoor unit
must be approved for use with HFC-410A. This unit is NOT
approved for use with coils which include metering orifices
or capillary tubes.
Factory Charge
The unit is factory-charged with the amount of HFC-410A
refrigerant indicated on the unit rating plate, This charge is
based on a matching indoor coil and outdoor coil with a 15
foot (4,6 m) line set. For varying lengths of line set, refer to
table 3 for refrigerant charge adjustment,

Page 12
504954M

0_06

HPXA16

Cooling

Cycle (Showing

Gauge

DISTRIBUTOR

Manifold
OUTDOOR

Connections)
UNIT
NOTE _ARROWS
INDICATE
DIRECTION OF REFRIGERANT

REVERSING

FLOW

VALVE

CHECK VALVE
BIFLOW
FILTER /
DRIER

LOW

OUTDOOR
COIL

HUGH

PRESSURE
EXPANSION/PRESSURE

INDOOR I INI
..---1

VAPOR
VA R VAPOR
PORT
SERVICE

svc
POR

COMPRESSOR

VALVE

EXPANSION/CHECK

Vl
i

VALVE --

-4_111

NOTE- Use gauge ports on vapor line valve and liquid valve for evacuating refrigerant lines and indoor coil. Use vapor
gauge port to measure vapor pressure during charging.

Figure
Table
Refrigerant

Charge

(20_C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.

per Line Set Lengths

Ounces per 5 feet (grams per 1.52 meter)
adjust from 15 ft. (4.57m) line set*

3/8 in. (9.5ram)

3 ounces per 5 feet (85 grams per 1.52 meter)

INDOOR
COIL

Liquid Line
Set Diameter

5. The outdoor temperature will determine which charging method to use. Proceed with whichever of the following charging procedure deemed appropriate for the
situation.

*Add the amount shown if line length is greater than 15' (4.57m), subtract the amount shown if less than 15'.

Charge Using the Weigh-in
Method Outdoor Temperature
< 65°F (18°C)
If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, first, locate and repair any leaks and
then weigh in the refrigerant charge into the unit.
1. Recover the refrigerant from the unit.

IMPORTANT

2. Conduct leak check; evacuate as previously outlined.
3. Weigh in the unit nameplate charge. If weighing facilities are not available or if charging the unit during
warm weather, use one of the following procedures.
Checking

Charge

The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is determined by the outdoor ambient temperature.
Measure the liquid line temperature and the outdoor ambient temperature as outlined below:
1. Connect the manifold gauge set to the service valves:
• low pressure gauge to vapor valve service port
• high pressure gauge to liquid valve service port
Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HFC-410A. See
figure 17.

Charge Using the Subcooling
Method Outdoor Temperature
< 65°F (18°C)
When the outdoor ambient temperature is below 65°F
(18°C), use the subcooling method to charge the unit. It
may be necessary to restrict the air flow through the outdoor coil to achieve pressures in the 325-375 psig
(2240-2585 kPa) range. These higher pressures are necessary for checking the charge. Block equal sections of air
intake panels and move obstructions sideways until the liquid pressure is in the 325-375 psig (2240-2585 kPa) range.
See figure 18.
locking

2. Set the room thermostat to call for heat. This will
create the necessary load for properly charging the
system in the cooling cycle.
3. Record outdoor ambient temperature
thermometer.

Coil

side at a time with cardboard or plastic
sheet
untilcoil
proper
testing
pressures
*Outdoor
should
be blocked
one
are reached.

using a digital

cardboard
*FouFsided

4. When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68 '_F

Outdoor

Figure

or plastic sheet
unit shown.

Page 13
HPXA16

SERIES

1. With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital thermometer to record the liquid line temperature.
2. At the same time, record the liquid line pressure reading,
3. Use a temperature/pressure
chart for HFC-410A to
determine the saturation temperature for the liquid line
pressure reading, See table 4.
Table 4
HFC-410A

Temperature

(°F) - Pressure

(Psig)

°F

Psig

°F

Psig

°F

Psig

°F

Psig

100.8

178.5

290.8

125

445.9

102.9

181.6

295.1

126

451.8

105.0

184.3

299.4

127

457.6

107.1

187.7

303.8

128

463.5

109.2

190.9

308.2

129

469.5

111.4

194.1

312.7

130

475.6

113.6

197.3

100

317.2

131

115.8

200.6

101

321.8

118.0

203.9

102

326.4

120.3

207.2

103

122.6

210.6

125.0

214.0

127.3

129.7

132.2

frigerant. Be aware of the HFC-410A refrigerant cylindec It will be light maroon-colored. Refrigerant should
be added through the vapor line valve in the liquid
state.
NOTE - Some HFC-410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from the bottom of the cylinder without turning the cylinder upsidedown. The cylinder will be marked if it is equipped with a dip
tube.
Table
Subcooling

Values

for Charging

Model Number

Second Stage (High Capacity)
Subcooling Values Conversion Temp. Liquid Line Temp. °F (°C)

HPXA16-024

11.0+ 1 (6 + .5)

481.6

HPXA16-036

8.5 + 1 (4.7 + .5)

132

487.8

HPXA16-048

7.5 + 1 (4.1 + .5)

133

494.0

HPXA16-060

7.0 + 1 (3.9 + .5)

331.0

134

500.2

104

335.7

135

506.5

105

340.5

136

512.9

217.4

106

345.3

137

519.3

220.9

107

350.1

138

525.8

224.4

108

355.0

139

532.4

134.6

228.0

109

360.0

140

539.0

137.1

231.6

110

365.0

141

545.6

139.6

235.3

111

370.0

142

552.3

142.2

239.0

112

375.1

143

559.1

144.8

242.7

113

380.2

144

565.9

147.4

246.5

114

385.4

145

572.8

150.1

250.3

115

390.7

146

579.8

152.8

254.1

116

396.0

147

586.8

155.5

258.0

117

401.3

148

593.8

158.2

262.0

118

406.7

149

601.0

161.0

266.0

119

412.2

150

608.1

163.9

270.0

120

417.7

151

615.4

166.7

274.1

121

423.2

152

622.7

169.6

278.2

122

428.8

153

630.1

172.6

282.3

123

434.5

154

637.5

175.4

286.5

124

440.2

155

645.0

Charge Using the Approach Method Outdoor Temperature
_>65°F (18°C)
The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results, indoor temperature should be 70°F (21°C) to 80°F
(26°C). Monitor system pressures while charging.
1. Record outdoor ambient temperature
thermometer,

2. Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize.
3. Compare stabilized pressures with those provided in
tables 6 and 7, "Normal Operating Pressures."

Xk IMPORTANT

4. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine subcooling. (Saturation temperature - Liquid line temperature = Subcooling)
5. Compare the subcooling value with those in table 5, If
subcooling is greater than shown, recover some refrigerant, If subcooling is less than shown, add some re-

Page 14
504954M

08/06

using a digital

Table 6
HPXA16
COOLING

Normal
(Liquid

Operating Pressures
+10 & Vapor +5 psig)*

-024
°F (°C)**

5. The difference between the ambient and liquid
temperatures should match values given in table 8. If
the values don't agree with the those in table 8, add
refrigerant to lower the approach temperature or
recover refrigerant from the system to increase the
approach temperature.

-036

-048

-060

uqlvopuqlvapu lvo u lvo

Table 8

First Stage (Low Capacity)
65 (18.3)

217

143

227

142

222

140

225

140

75 (23.9)

250

145

262

145

258

143

259

142

85 (29.4)

291

147

305

146

298

145

293

146

95 (35.0)

336

149

352

148

343

147

356

147

105 (40.6)

386

151

403

152

402

147

408

147

115 (49.0)

440

153

458

155

452

152

455

151

Approach

Second Stage (High Capacity) ApModel Number proach Temperature Liquid Line Temp. Outdoor Ambient °F (°C)

Second Stage (High Capacity)
65 (18.3)

222

143

244

136

232

134

249

126

75 (23.9)

256

145

282

139

266

136

289

134

85 (29.4)

302

145

325

142

309

139

330

140

95 (35.0)

349

147

377

144

359

142

378

143

105 (40.6)

403

149

428

146

410

144

433

146

115 (49.0)

464

152

488

148

468

147

492

149

*These

are most-popular-match-up

up, indoor

air quality, and indoor

**Temperature

pressures.

Indoor

load cause pressures

of the air entering

the outside

to vary

coil.

-048

-060

°F (°C)**

First Stage (Low Capacity)
40 (4.4)

321

296

315

319

50 (10)

340

120

310

112

330

114

335

111

Second Stage (High Capacity)
20 (-7.0)

273

277

294

300

30 (-1.0)

296

303

312

40 (4.4)

321

314

323

50 (10)

341

115

341

104

325

106

339

*These

are most-popular-match-up

up, indoor

air quality,

**Temperature

and indoor

of the air entering

pressures.

Indoor

load cause pressures
the outside

4.0 + 1 (2.2 + .5)

HPXA16-036

7.0 + 1 (3.9 + .5)

HPXA16-048

8.0 + 1 (4.4 + .5)

HPXA16-060

10.0 + 1 (5.6 + .5)

Thermostat
Operation
Some indoor thermostats incorporate isolating contacts
and an emergency heat function (which includes an amber
indicating light). The thermostat is not included with the
unit and must be purchased separately.

match

HPXA16 Normal Operating Pressures
HEATING (Liquid +10 & Vapor +5 psig)
-036

HPXA16-024

The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is in the ON position, the indoor blower operates continuously.

Table 7

-024

Values for Charging

Emergency
Heat (Amber Light)
An emergency heat function is designed into some room
thermostats. This feature is applicable when isolation d the
outdoor unit is required, or when auxiliary electric heat is
staged by outdoor thermostats. When the room thermostat is
placed in the emergency heat position, the outdoor unit control circuit is isolated from power and field-provided relays bypass the outdoor thermostats. An amber indicating light simultaneously comes on to remind the homeowner that he is
operating in the emergency heat mode.
Emergency heat is usually used during an outdoor unit
shutdown, but it should also be used following a power outage if power has been off for over an hour and the outdoor
temperature is below 50°F (10°C). System should be left in
the emergency heat mode at least six hours to allow the
crankcase heater sufficient time to prevent compressor
slugging.

match
to vary

Filter Drier

coil.

4. Use the same digital thermometer used to check
outdoor ambient temperature to check liquid line
temperature. Verify the unit charge using the approach
method.

The unit is equipped with
which keeps the system
necessary, order another
replacement filter drier
HFC-410A refrigerant.

a large-capacity biflow filter drier
clean and dry. If replacement is
of like design and capacity. The
must be suitable for use with

Page 15
HPXA16

SERIES

Defrost
Defrost System Description
The demand defrost controller measures differential temperatures to detect when the system is performing poorly
because of ice build-up on the outdoor coil. The controller
"self-calibrates" when the defrost system starts and after
each system defrost cycle. The defrost control board components are shown in figure 19.

Defrost
Note - Component

Control

Locations

Board

Vary by Board

TERMINATION
PIN SETTINGS
DEFROST

AMBIENT
THERMOSTAT
PINS

t_i

DELAY -PINS

Low Pressure Switch (LO-PS)--When the low pressure
switch trips, the defrost board will cycle off the compressor,
and the strike counter in the board will count one strike.
The low pressure switch is ignored under the following
conditions:
•

during the defrost cycle and 90 seconds after the termination of defrost

•

when the average ambient sensor temperature is below 15° F (-9°C)

•

for 90 seconds following the start up of the compressor

•

during "test" mode

Low Pressure
psig.

24V TERMINAL
STRIP
CONNECTIONS

Pressure

TIONS

The control monitors ambient temperature, outdoor coil
temperature, and total run time to determine when a defrost cycle is required. The coil temperature probe is designed with a spring clip to allow mounting to the outside
coil tubing. The location of the coil sensor is important for
proper defrost operation.
NOTE - The demand defrost board accurately measures
the performance of the system as frost accumulates on the
outdoor coil. This typically will translate into longer running
time between defrost cycles as more frost accumulates on
the outdoor coil before the board initiates defrost cycles.
Defrost

Board

Diagnostic

LEDs

The state (Off, On, Flashing) of two LEDs on the defrost
board (DS1 [Red] and DS2 [Green]) indicate diagnostics
conditions that are described in table 10 (on page 20).

08/06

Switch

5-Strike

Lockout

The 5-strike pressure switch lockout condition can be reset
by cycling OFF the 24-volt power to the control board or by
shorting the TEST pins between 1 to 2 seconds. All timer
functions (run times) will also be reset.
If a pressure switch opens while the Y1 Out line is engaged, a 5-minute short cycle will occur after the switch
closes.
Defrost System Sensors
Sensors connect to the defrost board through a field-replaceable harness assembly that plugs into the board (see
figure 21 ). Through the sensors, the board detects outdoor
ambient, coil, and discharge temperature fault conditions.
As the detected temperature changes, the resistance
across the sensor changes. Figure 20 shows how the resistance varies as the temperature changes for both type
of sensors. Sensor resistance values can be checked by
ohming across pins shown shown in table 9.

Page 16
504954M

(auto reset) - trip at 25 psig; reset at 55

The internal control logic of the board counts the pressure
switch trips only while the Y1 (Input) line is active. If a pressure switch opens and closes four times during a Y1 (Input), the control logic will reset the pressure switch trip
counter to zero at the end of the Y1 (Input). If the pressure
switch opens for a fifth time during the current Y1 (Input),
the control will enter a lockout condition.

PRESSURE /
SWITCH CIRCUIT CONNEC- _,

Figure

Connections

Defrost Board Pressure
Switch Settings
High Pressure (auto reset) - trip at 590 psig; reset at 418
psig.

LEDS

REVERSING
VALVE

Switch

High Pressure Switch (HI-PS)--When the high pressure
switch trips, the defrost board will cycle off the compressor,
and the strike counter in the board will count one strike.

PLUG IN
(COIL & AM_
BENT -SENSOR
SENSORS)

Pressure

The unit's automatic reset pressure switches (LO PS - $87
and HI PS - $4) are factory-wired into the defrost board on
the LO-PS and HI-PS terminals, respectively.

Manufacturer.

TEST PINS

Board

Table

NOTE - When checking the ohms across a sensor, be
aware that a sensor showing a resistance value that is not
within the range shown in table 9, may be performing as
designed. However, if a shorted or open circuit is detected,
then the sensor may be faulty and the sensor harness will
need to be replaced.
NOTE - Under certain ambient conditions, the internal
cabinet temperature of the HPXA16-036 cabinet will
affect the temperature that is sensed by the coil sensor. This can set up a condition
where the defrost
board may not initiate a defrost cycle. To overcome
this issue, the coil sensor should be moved to the alternate location on the other side of the cabinet to the
coil hairpin shown in figure 21.
Ambient

Sensor

Temperature

9
/ Resistance

Range
Pins/VV
ire
Color

Sensor

Temperature
Range °F (°C)

Resistance values
range (ohms)

Outdoor

-35 (-37) to 120 (48)

280,000 to 3750

3&4
(Black)

Coil

-35 (-37) to 120 (48)

280,000 to 3750

5& 6
(Brown)

Discharge (if
applicable)

24 (-4) to 350 (176)

41,000 to 103

1& 2
(Yellow)

Note: Sensor resistance decreases as sensed temperature
(see figure 20).

and Coil Sensor

increases

e Sensor
3OO

_7450

11775

15425

240

_425

_ 220

mmllmlml!19975
26200
m34375

200

180

160

140

m46275
I 62700
I

85300

30000

50000
RESISTANCE

825
B1175

WOO
,025

2500
3000

3750

¢650

70000

90000

lOOO

(OHMS)

2000

3000
RESISTANCE

Sensor
DISCHARGE
LINE SENSOR

5825

lOO

Figure

ALTERNATE
COIL
SENSOR
LOCATION.

_600

120

10000

260

m
m250
m
mm325

280

4000

5000

6000

(OHMS)

Locations

AMBIENT SENSOR (inside PVC tube) Extend
tip of plastic sensor just
outside of plastic sleeve.

COIL SENSOR DETAIL - Sensor
clips on the return bend as shown,
located on bends as follows:
HPXA16-024:
6th bend from top on outside
column.
HPXA16-036*, -048, -060:
5th bend from bottom on
outside column.
NOTE - DIAGRAMS ARE TYPICAL OF @24
AND @36 COIL; -048 & @60 COILS HAVE
MORE COIL SURFACE AREA AND
GREATER NUMBER OF BENDS.
* - @36 MODEL HAS ALTERNATE
LOCATION ON OPPOSITE SIDE AS SHOWN
TO THE LEFT

HPXA16-036 ALTERNATE
COIL SENSOR LOCATION

Figure

Page 17
HPXA16

SERIES

Defrost

System

Sensors

Ambient Sensor--The
ambient sensor considers outdoor temperatures below -35°F (-37°C) or above 120°F
(48°C) as a fault. If the ambient sensor is detected as being
open, shorted or out of the temperature range of the sensor, the board will not perform demand defrost operation.
The board will revert to time/temperature defrost operation
and will display the appropriate fault code. Heating and
cooling operation will be allowed in this fault condition.
Coil Sensor--The coil temperature sensor considers outdoor temperatures below -35°F (-37°C) or above 120°F
(48°C) as a fault. If the coil temperature sensor is detected
as being open, shorted or out of the temperature range of
the sensor, the board will not perform demand or time/temperature defrost operation and will display the appropriate
fault code. Heating and cooling operation will be allowed in
this fault condition.
Discharge Line Sensor--If
the discharge line temperature exceeds a temperature of 300°F (148°C) during compressor operation, the board will de-energize the compressor contactor output (and the defrost output, if active). The
compressor will remain off until the discharge temperature
has dropped below 225°F (107°C) and the 5-minute antishort cycle delay has been satisfied. This sensor has two
fault and lockout codes:
1. If the board recognizes five high discharge line temperature faults during a single (Y1) compressor demand, it reverts to a lockout mode and displays the appropriate code. This code detects shorted sensor or
high discharge temperatures. (Code on board is "Discharge Line Temperature Fault and Lockout").
2. If the board recognizes five temperature sensor range
faults during a single (Y1) compressor demand, it reverts to a lockout mode and displays the appropriate
code. The board detects open sensor or out-of-temperature sensor range. This fault is detected by allowing the unit to run for 90 seconds before checking sensor resistance. If the sensor resistance is not within
range after 90 seconds, the board will count one fault.
After 5 faults, the board will lockout. (Code on board
is "Discharge Sensor Fault and Lockout").

If first-stage compressor output is active in heating mode
and the outdoor ambient temperature is below the selected
compressor lock-in temperature, the second-stage compressor solenoid output will be energized without the "Y2"
input. If the jumper is not connected to one of the temperature selection pins on P3 (40, 45, 50, 55°F), the default
lock-in temperature of 40°F (4.5°C) will be used.
The board de-energizes the second-stage compressor solenoid output immediately when the "Y2" signal is removed
or the outdoor ambient temperature is 5°F above the selected compressor lock-in temperature, or the first-stage
compressor output is de-energized for any reason.
Defrost Temperature
Termination
Shunt (Jumper)
Pins--The defrost board selections are: 50, 70, 90, and
100°F (10, 21, 32 and 38°C). The shunt termination pin is
factory set at 50°F (10°C). If the temperature shunt is not
installed, the default termination temperature is 90°F
(32°C).
Delay Mode
The defrost board has a field-selectable function to reduce
occasional sounds that may occur while the unit is cycling
in and out of the defrost mode. When a jumper is installed
on the DELAY pins, the compressor will be cycled off for 30
seconds going in and out of the defrost mode. Units are
shipped with jumper installed on DELAY pins.
NOTE - The 30 second off cycle is NOT functional when
jumpering the TEST pins.
Operational
Description
The defrost control board has three basic operational
modes: normal, defrost, and calibration.
•

•

The discharge line sensor, which covers a range of 150°F
(65°C) to 350°F (176°C), is designed to mount on a V:" refrigerant discharge line.
•
NOTE - Within a single room thermostat demand, if
5-strikes occur, the board will lockout the unit. Defrost
board 24 volt power "R" must be cycled "OFF" or the
"TEST" pins on board must be shorted between 1 to 2 seconds to reset the board.
Second-Stage Operation--If the board receives a call for
second-stage compressor operation "Y2" in heating or
cooling mode and the first-stage compressor output is active, the second-stage compressor solenoid output will be
energized.
NOTE - Figure 8 on page 5 shows the correct Y2 field wiring.

0_06

Defrost Mode--The following paragraphs provide a
detailed description of the defrost system operation.

Detailed Defrost System Operation
The demand defrost control board initiates a defrost cycle
based on either frost detection or time.
Frost Detection--If
the compressor runs longer than 34
minutes and the actual difference between the clear coil
and frosted coil temperatures exceeds the maximum difference allowed by the control, a defrost cycle will be initiated.
IMPQR TANT - The demand defrost control board will allow
a greater accumulation of frost and will initiate fewer defrost cycles than a time/temperature defrost system.

Page 18
504954M

Normal Mode--The demand defrost board monitors
the O line, to determine the system operating mode
(heat/cool), outdoor ambient temperature, coil temperature (outdoor coil) and compressor run time to determine when a defrost cycle is required.
Calibration Mode--The board is considered uncalibrated when power is applied to the board, after cool
mode operation, or if the coil temperature exceeds the
termination temperature when it is in heat mode.
Calibration of the board occurs after a defrost cycle to
ensure that there is no ice on the coil. During calibration, the temperature of both the coil and the ambient
sensor are measured to establish the temperature differential which is required to allow a defrost cycle.

Time--If 6 hoursof heatingmodecompressor
runtime
haselapsedsincethelastdefrostcyclewhilethecoiltemperatureremainsbelow35°F(2°C),thedemanddefrost
controlwillinitiatea defrostcycle.
Actuation--Whenthe reversingvalveis de-energized,
theY1circuitis energized,
andthecoiltemperature
is below35°F(2°C),theboardlogsthecompressor
runtime,If
theboardis notcalibrated,
a defrostcyclewillbeinitiated
after34minutesof heatingmodecompressor
runtime.
Thecontrolwillattempttoself-calibrate
afterthis(andall
other)defrostcycle(s),
Calibration
successdependsonstablesystemtemperaturesduringthe20-minute
calibration
period,Iftheboard
failstocalibrate,
anotherdefrostcyclewillbeinitiatedafter
90minutesof heatingmodecompressor
runtime,Once
thedefrostboardis calibrated,
itinitiatesademanddefrost
cyclewhen the differencebetweenthe clearcoil and
frostedcoiltemperatures
exceedsthe maximumdifferenceallowedby thecontrolORafter6 hoursof heating
modecompressor
runtimehasbeenloggedsincethelast
defrostcycle.
Termination--Thedefrostcycleendswhenthecoiltemperatureexceedsthetermination
temperature
or after14
minutesofdefrostoperation.
Ifthedefrostisterminated
by
the14-minute
timer,anotherdefrostcyclewillbeinitiated

after34minutesofruntime.
Test Mode--[NOTE - Coil sensor temperature must be
below 35°F before the defrost board will initiate a
"test" defrost.] When Y1 is energized and 24V power is
being applied to the board, a test cycle can be initiated by
placing the termination temperature jumper across the
"Test" pins for 2 to 5 seconds. If the jumper remains across
the "Test" pins longer than 5 seconds, the control will ignore the test pins and revert to normal operation, The
jumper will initiate one cycle per test,
Enter the "TEST" mode by placing a shunt (jumper) across
the "TEST" pins on the board after power-up. (The "TEST"
pins are ignored and the test function is locked out if the
shunt is applied on the "TEST" pins before power-up),
Board timings are reduced, the low-pressure switch is ignored and the board will clear any active lockout condition,
Each test pin shorting will result in one test event. For
each "TEST" the shunt (jumper) must be removed for at
least 1 second and reapplied, Refer to flow chart (figure
22) for "TEST" operation,
Note: The Y1 input must be active (ON) and the "0" room
thermostat terminal into board must be inactive.
Defrost Board Diagnostics
See table 10 to determine defrost board operational conditions and to diagnose cause and solution to problems.

Test Mode
I

Y1 Active ("0" line inactive)
I

]

Short test pins for more than 2.0 seconds

Short test pins for longer
than I second but less
than 2,0 seconds

Clear any short cycle lockout or 5-strike fault
lockout function, if applicable.

If in HEATING Mode
I [
Clear any short cycle lockout I If in COOLING Mode I I
and/or 5-strike fault lockout
function, if applicable. No
No further test mode
The controller will check for
other functions will be
operation will be
ambient and coil faults (open or
executed and unit will
executed until the test
shorted). If a fault exists the unit
continue in the mode it was
short is removed and
will remain in Heat Mode and no
operating.

reapplied.

further test mode operation will
be executed until the test short
is removed and re applied. If
no fault exists and ambient
temperature is below 35°F, the
unit will go into Defrost mode.
F

Test pin short REMAINS in place for more than 5 seconds
The unit will return to Heat mode uncalibrated with defrost
timer set for 34 minutes. No further test mode operation will
be executed until the test short is removed and re applied.
Figure

If in DEFROST Mode
The unit will terminate
defrost and enter Heat
Mode uncalibrated with
defrost timer set for 34
minute test. No further
test mode operation will
be executed until the test
short is removed and
reapplied.

Test pins short REMOVED before a
maximum of 5 seconds
The unit will remain in Defrost mode
until termination on time or temperature

Page 19
HPXA16

SERIES

Table 10
Defrost

Control

Board Diagnostic

LEDs

DS2
Green

DS1
Red

Condition/Code

Possible

OFF

Power problem

No power (24V) to board terminals R & C or board failure.

1 Check control transformer power (24V).
2 If power is available to board and LED(s) do
not light, replace board.

Simultaneous
SLOW Flash

Normal operation

Unit operating normally or in
standby mode.

None required.

Alternating
SLOW Flash

5-minute anti-short cycle
delay

Initial power up, safety trip, end of
room thermostat demand.

None required (Jumper TEST pins to override)

Simultaneous
FAST Flash

Ambient Sensor Problem

Sensor being detected open or shorted or out of temperature range. Board will revert to time/temperature defrost operation. (System will still heat or cool).

Alternating
FAST Flash

Coil Sensor Problem

Sensor being detected open or shorted or out of temperature range. Board will not
perform demand or time/temperature defrost operation. (System will still heat or
cool).

Circuit Board Failure

code
Indicates
doesthat
notboard
clear, has
replace
internal
board,
component failure. Cycle 24 volt power to board. If

FAULT

& LOCKOUT

OFF

SLOW
Flash

Low Pressure Fault

OFF

Low Pressure

SLOW
Flash

OFF

High Pressure

OFF

High Pressure LOCKOUT

SLOW
Flash

Discharge Line Temperature Fault

FAST
Flash

Discharge Line Temperature LOCKOUT

OFF

Fast
Flash

Discharge Sensor Fault

Fast
Flash

OFF

Discharge
LOCKOUT

CODES

(Each

fault adds 1 strike to that code's

LOCKOUT

Fault

Sensor

Cause(s)

0_06

counter;

5 strikes

per code = LOCKOUT)

1 Restricted air flow over indoor or 1 Remove any blockages or restrictions from
outdoor coil.
coils and/or fans. Check indoor and outdoor
2 Improper refrigerant charge in
fan motor for proper current draws.
2 Check system charge using approach & subsystem.
3 Improper metering device
cooling temperatures.
installed or incorrect operation
3 Check system operating pressures and
of metering device.
compare to unit charging charts.
4 Incorrect or improper sensor
4 Make sure all pressure switches and sensors
location or connection to syshave secure connections to system to prevent
tem.
refrigerant leaks or errors in pressure and
temperature measurements.
This code detects shorted sensor or high discharge temperatures. If the discharge
line temperature exceeds a temperature of 300°F (148°C) during compressor operation, the board will de-energize the compressor contactor output (and the defrost
output if active). The compressor will remain off until the discharge temperature has
dropped below 225°F (107°C).
The board detects open sensor or out of temperature sensor range. This fault is
detected by allowing the unit to run for 90 seconds before checking sensor resistance. If the sensor resistance is not within range after 90 seconds, the board will
count one fault. After 5 faults, the board will lockout.

Page 20
504954M

Solution

,WARNING

Before the start of each heating and cooling season, the
following service checks should be performed by a qualified service technician. First, turn off electrical power to the
unit prior to performing unit maintenance,
•

Inspect and clean the outdoor and indoor coils, The
outdoor coil may be flushed with a water hose,
NOTE - It may be necessary to flush the outdoor coil
more frequently if it is exposed to substances which
are corrosive or which block airflow across the coil
(e.g., pet urine, cottonwood seeds, etc.)

•

Visually inspect the refrigerant lines and coils for leaks,

•

Check the condensate drain line for free and unobstructed flow; clean, if necessary.

•

Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM
Refer to the unit information service manual for pressure
drop tables and procedure.

•

Check drive belt for wear and proper tension.
NOTE - If owner reports insufficient cooling, the unit
should be gauged and refrigerant charge checked. Refer to section on refrigerant charging in this instruction.

Refer to the Engineering Handbook for optional accessories that may apply to this unit. The following may or may
not apply:
•

Loss of charge kit

•

High pressure switch kit

•

Compressor monitor

•

Compressor crankcase heater
Hail guards

•

Check wiring for loose connections,

•

Check voltage at the indoor and outdoor units (with
units operating),

•

Mounting bases

•

Timed-off control

Check the amperage draw at the outdoor fan motor,
compressor, and indoor blower motor. Values should
be compared with those given on unit nameplate,

•

Stand-off Kit

•

Sound cover

•

Low ambient kit

•

Monitor kit

•

Dave Lennox SignatureStat

•

Check, clean (or replace) indoor unit filters,

•

Check the refrigerant charge and gauge the system
pressures,

Room Thermostat

Page 21
HPXA16

SERIES

Job Name

Job no.

Date

Job Location

City

State

Installer

City

State

Unit Model No,

Serial No.

Service Technician

Nameplate Voltage
Rated Load Ampacity

Compressor Amperage: 1st Stage

2nd Stage:

Maximum Fuse or Circuit Breaker
Electrical Connections Tight?
Indoor Blower RPM

Indoor Filter clean?
S.P. Drop Over Indoor (Dry)

Supply Voltage (Unit Off)
Outdoor Coil Entering Air Temp.

COOLING (2ND STAGE)
Liquid Line Pressure:

Vapor Pressure:

Refrigerant Charge Checked?

Liquid Line Pressure:

Vapor Pressure:

Refrigerant Charge Checked?

Vapor Pressure; 1st Stage:

2nd Stage:

HEATING (2ND STAGE)

Refrigerant

Lines: - Leak Checked?

Service Valves:

---

Fully Opened?

SEQUENCE
Heating Correct?

Properly Insulated?

Outdoor Fan Checked?

Caps Tight?

Voltage With Compressor Operating
THERMOSTAT

OF OPERATION
Cooling Correct?

Calibrated?

Page 22
504954M

08/06

Properly Set? _

Level?

:c'2006 Lennox industries Inc,
Dallas, Texas, USA

HPXA16

In order to ensure peak performance, your system must be
properly maintained. Clogged filters and blocked airflow
prevent your unit from operating at its most efficient level.

A IMPORTANT

1. Ask your Lennox dealer to show you where your indoor
unit's filter is located. It will be either at the indoor unit
(installed internal or external to the cabinet) or behind
a return air grille in the wall or ceiling. Check the filter
monthly and clean or replace it as needed.
2. Disposable filters should be replaced with a filter of the
same type and size.
NOTE - If you are unsure about the filter you need for
your system, call your Lennox dealer for assistance.

Heat Pump Operation
Your new Lennox heat pump has several characteristics
that you should be aware of:
•

A IMPORTANT
•

3. Many indoor units are equipped with reusable foam filters. These filters can be cleaned with a mild soap and
water solution. Rinse the filter thoroughly and let it dry
completely before it is returned to the unit or grille.
NOTE - The filter and all access panels must be M
place any time the unit is in operation.
4. Some systems are equipped with an electronic air
cleaner, designed to remove the majority of airborne
particles from the air passing through the cleaner. If
your system is so equipped, ask your dealer for maintenance instructions.
5. Inspect and clean indoor coil. The indoor evaporator
coil is equipped with a drain pan to collect condensate
formed as your system removes humidity from the inside air. Have your dealer show you the location of the
drain line and how to check for obstructions. (This
would also apply to an auxiliary drain, if installed.)

•

Heat pumps satisfy heating demand by delivering
large amounts of warm air into the living space. This
is quite different from gas- or oil4ired furnaces or an
electric furnace which deliver lower volumes of considerably hotter air to heat the space.
Do not be alarmed if you notice frost on the outdoor coil
in the winter months. Frost develops on the outdoor
coil during the heating cycle when temperatures are
below 45°F (7°C). An electronic control activates a defrost cycle lasting 5 to 15 minutes at preset intervals
to clear the outdoor coil of the frost.
During the defrost cycle, you may notice steam rising
from the outdoor unit. This is a normal occurrence. The
thermostat may engage auxiliary heat during the defrost cycle to satisfy a heating demand; however, the
unit will return to normal operation at the conclusion of
the defrost cycle.

In case of extended
power outage...
The heat pump is equipped with a compressor crankcase
heater which protects the compressor from refrigerant
"slugging" during cold weather operation.
If power to your unit has been interrupted for several hours
or more, set the room thermostat selector to the "Emergency Heat" setting to obtain temporary heat without the
risk of serious damage to the heat pump.
In Emergency Heat mode, all heating demand is satisfied
by auxiliary heat; heat pump operation is locked out. After a
six-hour compressor crankcase "warm-up" period, the
thermostat can be switched to the "Heat" setting and normal heat pump operation may resume.

Page 23
HPXA16

SERIES

Though your thermostat may vary somewhat from the description below, its operation will be similar,

dicates when the heat pump is operating in the emergency
heat mode,

Temperature
Setting
Levers
Most heat pump thermostats have two temperature selector levers: one for heating and one for cooling, Set the levers or dials to the desired temperature setpoints for both
heating and cooling. Avoid frequent temperature adjustment; turning the unit off and back on before pressures
equalize puts stress on the unit compressor,

Temperature
Indicator
The temperature indicator displays the actual room temperature,

Fan Switch
In AUTO or INT (intermittent) mode, the blower operates
only when the thermostat calls for heating or cooling. This
mode is generally preferred when humidity control is a
priority. The ON or CONT mode provides continuous indoor blower operation, regardless of whether the compressor or auxiliary heat are operating. This mode is required when constant air circulation or filtering is desired,

Programmable
Thermostats
Your Lennox system may be controlled by a programmable thermostat. These thermostats provide the added
feature of programmable time-of-day setpoints for both
heating and cooling. Refer to the user's information manual provided with your particular thermostat for operation
details,
Preservice

Check

If your system fails to operate, check the following before
calling for service:
•
Check to see that all electrical disconnect switches are
ON.

System Switch
Set the system switch for heating, cooling or auto operation, The auto mode allows the heat pump to automatically
switch from heating mode to cooling mode to maintain predetermined comfort settings. Many heat pump thermostats are also equipped with an emergency heat mode
which locks out heat pump operation and provides temporary heat supplied by the auxiliary heat,

•

Make sure the room thermostat temperature selector
is properly set.

•

Make sure the room thermostat system switch is properly set.

•

Replace any blown fuses, or reset circuit breakers,

•
•

Make sure unit access panels are in place,
Make sure air filter is clean,

Indicating
Light
Most heat pump thermostats have an amber light which in-

•

Locate unit model number and have it handy before
calling,

Page 24
504954M

0_06

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.2
Linearized                      : No
Page Count                      : 24
Page Layout                     : SinglePage
Page Mode                       : UseNone
Producer                        : Goby Monitor Application version 4, 0, 0, 13
Create Date                     : Mon Jun 30 05:00:25 2008
Author                          : 
Title                           : 
Subject                         :

EXIF Metadata provided by EXIF.tools

LENNOX Air Conditioner/heat Pump(outside Unit) Manual L0806497

Navigation menu

Versions of this User Manual:

Views

Navigation