Lennox HPXA15-024, HPXA15-036, HPXA15, HPXA15-030, HPXA15-048 Installation Instructions Manual



INSTALLATION

2002 Lennox Industries Inc.

Dallas, Texas

HPXA15 Outdoor Unit

HPXA15 outdoor units use R410A which is an ozone
friendly HFC refrigerant. This unit must be installed with a
matching indoor coil and line set as outlined in the Lennox
Engineering Handbook. HPXA15 outdoor units are de­signed for use in expansion valve (TXV) systems only.
They are not designed to be used with other refrigerant flow
control devices. An expansion valve approved for use with
R410A has been shipped with the unit and must be
installed prior to operating the unit.

Shipping and Packing List

INSTRUCTIONS

HPXA15 SERIES UNITS

HEAT PUMP UNITS

504,713M
02/04

Supersedes 12/02

Table of Contents

HPXA15 Outdoor Unit 1. . . . . . . . . . . . . . . . . . . . . . . . . . .

Shipping & Packing List 1. . . . . . . . . . . . . . . . . . . . . . . . .

General Information 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Setting the Unit 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Refrigerant Piping 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flushing Existing Line Set & Indoor Coil 10. . . . . . . . . .

Manifold Gauge Set 12. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Valves 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Leak Testing 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Evacuation 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Charging 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Operation 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Defrost System 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HPXA15 Check Points 21. . . . . . . . . . . . . . . . . . . . . . . . .

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

IMPORTANT

This unit must be matched with an indoor coil as
specified in Lennox’ Engineering Handbook. Coils
previously charged with R22 must be flushed.

Litho U.S.A.

1 − Assembled HPXA15 outdoor unit

2 − Grommets (for liquid and vapor lines)

Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.

General Information

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

Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person­al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.

02/04

*2P0204*

Page 1

WARNING

This product and/or the indoor unit it is matched with
may contain fiberglass wool.

Disturbing the insulation during installation, mainte­nance, or repair will expose you to fiberglass wool
dust. Breathing this may cause lung cancer. (Fiber­glass wool is known to the State of California to
cause cancer.)

Fiberglass wool may also cause respiratory, skin,
and eye irritation.

To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.

Lennox Industries Inc.

P.O. Box 799900
Dallas, TX 75379−9900

504,713M

*P504713M*

Dimensions −− Inches (mm)

HPXA15-030

HPXA15-048

inlet

air

inlet

air

compressor

inlet air

Top View

B

inlets

electrical

C

coil drain outlets

(around perimeter

of base)

discharge air

vapor

line inlet

A

4-1/2 (114)

H

liquid

D

2-9/16

(65)

line inlet

K

J

4-7/8 (22)

2

(51)

K

J

G

2

(51)

2-3/4

(70)

1-3/8

(35)

4

(102)

F

E

Side ViewService Access

Model No. A B C D E F G H J K

HPXA15-024

HPXA15-030
HPXA15-036

HPXA15-042

HPXA15-048
HPXA15−060

in. 27-7/8 25-7/8 29-7/8 12-1/4 22-7/16 14-7/16 22-1/8 16-3/4 2-7/8 5-1/2

mm 708 657 759 311 570 367 562 425 730 140

in. 30-7/8 32-1/8 34-1/16 12-3/4 26-5/8 18-5/8 28-1/8 17-1/4 3-7/8 7-1/2

mm 784 816 865 324 676 473 718 438 98 191

in. 34-7/8 32-1/8 34-1/16 13-3/4 26-5/8 18-5/8 28-1/8 18-1/4 3-7/8 7-1/2

mm 886 816 865 349 676 473 718 464 98 191

in. 44-7/8 32-1/8 34-1/16 14-1/4 26-5/8 18-5/8 28-1/8 18-3/4 3-7/8 7-1/2

mm 1140 816 865 362 676 473 718 476 98 191

4

(102)

6-1/16

(154)

Page 2

Parts Arrangement

dual capacitor

high pressure

switch

filter/drier

expansion valve

with internal check valve

defrost

thermostat

distributor

compressor

terminal box

defrost control/timed−off control

compressor

crankcase

heater

contactor

ground lug

sensing bulb

vapor line

service valve

and gauge port

liquid line

service valve

and gauge port

crankcase heater

thermostat

(2−1/2 through

5−ton units)

reversing valve

and solenoid

muffler

Figure 1

Setting the Unit

CAUTION

In order to avoid injury, take proper precaution when
lifting heavy objects.

CAUTION

Sharp sheet metal edges can cause injury. When
installing the unit, avoid accidental contact with
sharp edges.

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. A minimum clearance of 24 inches (610 mm) between
multiple units must be maintained. 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.

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.

Installation Clearances

*36"

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" (304 mm)
and the final side may be 6"
(152 mm).

NOTE − A clearance of 24" (610 mm)
must be maintained between two units.

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

36"

(914 mm)

(914 mm)

*36"

(914 mm)

36"

(914 mm)

Figure 2

4 − When installed in areas where low ambient tempera-

tures exist, locate unit so winter prevailing winds do
not blow directly into outdoor coil.

Page 3

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.

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.

Rooftop Application

Wind Barrier Construction

prevailing winter winds

wind barrier

inlet air

(610 mm)

INLET

AIR

24"

2 degrees or

2 in. per 5 foot

(51 mm per 1.5 m)

slope tolerance away

from building structure

ground level

Slab Mounting

discharge air

building

structure

mounting

slab

Figure 3

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 3.
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.

inlet air

Figure 4

Electrical

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).

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

Unit must be grounded in accordance with national
and local codes.
ELECTRIC SHOCK HAZARD.
Can cause injury or death.

1 −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.

Page 4

NOTE − To facilitate conduit, a hole is in the bottom of
the control box. Connect conduit to the control box us
ing a proper conduit fitting.

NOTE − Units are approved for use only with copper
conductors.

24V, Class II circuit connections are made in the low
voltage junction box. Refer to figure 5 for field wiring
diagram.

NOTE − A complete unit wiring diagram is located in

Typical Field Wiring Diagram

side the unit control box cover.

3 − Install room thermostat (ordered separately) on an in-

side wall approximately in the center of 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.

4 − Install voltage wiring from outdoor to indoor unit and

from thermostat to indoor unit. See figures 6 and 7.

Figure 5

Page 5

Outdoor Unit and Blower Unit

Thermostat Designations

(Some connections may not apply.

Refer to specific thermostat and indoor unit.)

Thermostat

R

C

1st. stage aux. heat

W1

G

O

Y1

Indoor

Unit

power

common common

indoor blower

reversing valve

compressor

R

C

W1

W2

W3

G

power

1st. stage aux. heat

Outdoor

Unit

R

C

W1

O

Y1

Figure 6

Outdoor Unit and Blower Unit

Thermostat Designations

(with auxiliary heat)

(Some connections may not apply.

Refer to specific thermostat and indoor unit.)

Thermostat

R

C

emergency heat

E

W1

1st. stage aux. heat

indoor blower

G

reversing valve

O

compressor

Y1

Indoor

Unit

power

common common

R

C

em.

heat rly

W1

1st. stage aux. heat

W2

W3

G

Outdoor

power

outdoor t’stat

Unit

R

C

W1

O

Y1

Figure 7

Refrigerant Piping

If the HPXA15 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 HPXA15 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 1 or use field-fabri­cated refrigerant lines. Refer to Refrigerant Piping Guide
(Corp. 9351−L9) for proper size, type, and application of
field−fabricated lines. Valve sizes are also listed in table 1.

Refrigerant Connections

HPXA15 Matched with New Indoor Coil and Line Set

If an existing indoor coil which was equipped with an
RFCI metering device is being replaced, the liquid line
must also be replaced prior to the installation of the
HPXA15 unit.

Table 1

Refrigerant Line Sets

Valve Field Size

Connections

Model

−024

−030

−036

−042

−048

−060

Liquid

Line

3/8 in.

10 mm

3/8 in.

10 mm

3/8 in.

10 mm

Vapor

Line

3/4 in.

19 mm

7/8 in.

22 mm

1−1/8 in.

29 mm

NOTE − Units are designed for line sets of up to 50 feet (15
m). For applications longer than 50 feet, consult the Len­nox Refrigerant Piping Guide (Corp. 9351−L9). Select line
set diameters from table 1 to ensure that oil returns to the
compressor.

Installing Refrigerant Line

During the installation of any heat pump or a/c system, it is
important to properly isolate the refrigerant lines to prevent
unnecessary vibration. Line set contact with the structure
(wall, ceiling or floor) causes some objectionable noise
when vibration is translated into sound. As a result, more
energy or vibration can be expected. Closer attention to
line set isolation must be observed.

Following are some points to consider when placing and
installing a high−efficiency outdoor unit:

Recommended Line Set

Liquid

Line

3/8 in.

10 mm

3/8 in.

10 mm

3/8 in.

10 mm

Vapor

Line

3/4 in.

19 mm

7/8 in.

22 mm

1−1/8 in.

29 mm

15 ft. − 50 ft.

4.6 m − 15 m

15 ft. − 50 ft.

4.6 m − 15 m

L15

Line Sets

L15−41

L15−65

Field

Fabricated

Page 6

1- Placement − Be aware some localities are adopting

sound ordinances based on how noisy the unit is from
the adjacent property 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
window. Glass has a very high level of sound transmis­sion.

Refrigerant Line Sets

How To Install Vertical Runs

(new construction shown)

NOTE - Similar installation practices should be used if
line set is to be installed on exterior of outside wall.

2- Line Set Isolation − The following illustrations demon-

strate procedures which ensure proper refrigerant line
set isolation. Figure 8 shows how to install line sets on
vertical runs. Figure 9 shows how to install line sets on
horizontal runs. Figure 10 shows how to make a transi­tion from horizontal to vertical. Finally, figure 11 shows
how to place the outdoor unit and line set.

Outside Wall

Wood Block

Between Studs

Liquid Line

Vapor Line

(wrapped with Armaflex)

Outside Wall

IMPORTANT - Refrigerant

lines must not contact wall.

Liquid LineVapor Line

Wire Tie

Inside Wall

Strap

Sleeve

Wire Tie

Wood Block

Wire Tie

Caulk

PVC Pipe

Fiberglass

Insulation

IMPORTANT - Refrigerant

lines must not contact

structure.

Strap

Sleeve

Figure 8

Page 7

Installing Horizontal Runs

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

Floor Joist or

Roof Rafter

Refrigerant Line Sets:

Wire Tie

(around vapor line only)

8 feet

Tape or Wire Tie

8 feet

Strapping Material (around vapor line only)

Tape or Wire Tie

Metal Sleeve

Floor Joist or Roof Rafter

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

Figure 9

Page 8

Refrigerant Line Sets:

Transition From Vertical To Horizontal

Anchored Heavy

Nylon Wire Tie

Wall
Stud

Metal

Sleeve

Muffler-Type

Wall
Stud

Strap Liquid Line

To Vapor Line

Vapor Line

Wrapped in

Armaflex

Liquid Line

Figure 10

Outside Unit Placement and Installation

Automotive

Hanger

Metal

Sleeve

Strap Liquid Line

To Vapor Line

Liquid Line

Vapor Line

Wrapped in

Armaflex

Install unit away from windows.

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

Figure 11

Page 9

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.

Metering Device Installation

distributor

expansion

valve

o−ring

WARNING

Polyol ester (POE) oils used with R410A refrigerant
absorb moisture very quickly. It is very important
that the refrigerant system be kept closed as much
as possible. DO NOT remove line set caps or ser­vice valve stub caps until you are ready to make
connections.

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.)

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.

3 − Use silver alloy brazing rods (5 or 6 percent minimum

silver alloy for copper−to−copper brazing or 45 percent
silver alloy for copper−to−brass or copper−to−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.

4 − Quench the joint with water or a wet cloth to prevent

heat damage to the valve core and opening port.

IMPORTANT − The tube end must stay bottomed in the
fitting during final assembly to ensure proper seating,
sealing and rigidity.

Refrigerant Metering Device

HPXA15 units are used in check expansion valve systems
only. See the Lennox Engineering Handbook for approved
TXV match-ups and application information.

Check expansion valves equipped with Chatleff fittings
are available from Lennox. Refer to the Engineering
Handbook for applicable 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
installing the check expansion valve.

See figure 1 for installation of the check expansion valve.

o−ring

strainer

liquid line

stub

Figure 1

IMPORTANT

Failure to remove RFC orifice when installing an ex­pansion valve on the indoor coil will result in improp­er operation and damage to the system.

Flushing Existing Line Set & Indoor Coil

WARNING

Danger of fire. Bleeding the refrigerant
charge from only the high side may
result in the low side shell and suc­tion tubing being pressurized. App­plication of a brazing torch while pres­surized may result in ignition of the
refrigerant and oil mixture − check the
high and low pressures before unbra­zing.

IMPORTANT

If this unit is being matched with an approved line
set or indoor coil that was previously charged with
R22 refrigerant, or if it is being matched with a coil
that was manufactured before January of 1999, the
coil and line set must be flushed prior to installation.
Take care to empty all existing traps. Polyol ester
(POE) oils are used in Lennox units charged with
R410A refrigerant. Residual mineral oil can act as an
insulator, preventing proper heat transfer. It can
also clog the thermal expansion valve, reducing
system performance and capacity.
Failure to properly flush the system per the instruc­tions below will void the warranty.

CAUTION

This procedure should not be performed on sys­tems which contain contaminants (Example: com­pressor burn out).

Page 10

Required Equipment

You will need the following equipment in order to flush the
existing line set and indoor coil: two clean R22 recovery
bottles, an oilless recovery machine with a pump down fea­ture, and two sets of gauges (one for use with R22 and one
for use with the R410A).

Flushing Procedure

1 − Remove existing R22 refrigerant using the appropri-

ate 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 R22 refrigerant to
flush the system −− Disconnect all power to the exist-

ing outdoor unit. Connect the existing unit, a clean re­covery cylinder and the recovery machine according
to the instructions provided with the recovery ma­chine. Remove all R22 refrigerant from the existing
system. Refer to 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.

If the existing outdoor unit is equipped with manu­al shut−off valves AND you plan to use NEW R22
refrigerant to flush the system −− Start the existing

R22 system in the cooling mode and close the liquid
line valve. Pump all of the existing R22 refrigerant
back into the outdoor unit. (It may be necessary to by­pass the low pressure switches to ensure complete re-

frigerant evacuation.) When the low side system pres­sures reach 0 psig, close the vapor line valve.
Disconnect all power to the existing outdoor unit. Re­fer to 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 R410A

unit and follow the brazing connection procedure
which begins on the previous page to make line set
connections. DO NOT install provided R410A

check/expansion valve at this time.

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.

3 − 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 R410A refrigerant and may pre­vent proper flushing. Use a field−provided fitting to re­connect the lines.

IMPORTANT

The line set and indoor coil must be flushed with at
least the same amount of clean refrigerant that pre­viously charged the system. Check the charge in
the flushing cylinder before proceeding.

Existing

Indoor Coil

RECOVERY

CYLINDER

Flushing Connections

Inverted R22 Cylinder

(Contains clean R22 to

be used for flushing)

EXISTING VAPOR LINE

EXISTING LIQUID LINE

VAPOR LINE

SERVICE VALVE

LIQUID LINE

SERVICE VALVE

TANK RETURN

INLET

DISCHARGE

Recovery Machine

Figure 12

LOW

PRESSURE

HPXA15 Unit

GAUGE MANIFOLD

NOTE − The inverted R22 cylinder must con­tain at least the same amount of refrigerant
as was recovered from the existing system.

HIGH

PRESSURE

CLOSEDOPENED

Page 11

4 − Remove the pressure tap valve cores from the

HPXA15 unit’s service valves. Connect an R22 cylin­der with clean refrigerant to the vapor service valve.
Connect the R22 gauge set to the liquid line valve and
connect a recovery machine with an empty recovery
tank to the gauge set.

5 − 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.

6 − Invert the cylinder of clean R22 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.

7 − After all of the liquid refrigerant has been recovered,

switch the recovery machine to vapor recovery so that
all of the R22 vapor is recovered.

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.

8 − Close the valve on the inverted R22 drum and the

gauge set valves. Pump the remaining refrigerant out
of the recovery machine and turn the machine off.

9 − Use nitrogen to break the vacuum on the refrigerant

lines and indoor coil before removing the recovery ma­chine, gauges and R22 refrigerant drum. Reinstall
pressure tap valve cores into HPXA15 service valves.

10 −Install the provided check/expansion valve (approved

for use with R410A refrigerant) in the liquid line at the
indoor coil.

Manifold Gauge Set

Manifold gauge sets used with systems charged with
R410A 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.

Service Valves

Access the liquid line and vapor line service valves (figures
13 and 14) and gauge ports are used for leak testing, eva­cuating, charging and checking charge. See table 1 for
torque requirements.

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.

Table 1

Torque Requirements

Part Recommended Torque

Service valve cap 8 ft.− lb. 11 N M

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 N M

IMPORTANT

Service valves are closed to the outdoor unit and
open to line set connections. Do not open the valves
until refrigerant lines have been leak tested and
evacuated. All precautions should be exercised to
keep the system free from dirt, moisture and air.

To Access Schrader Port:

1 − Remove service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is complete, replace service port cap.

Tighten finger tight, then an additional 1/6 turn.

To Open Service Valve:

1 − Remove stem cap with an adjustable wrench.
2 − Using service wrench and hex head extension, back

the stem out counterclockwise as far as it will go.

NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.

3 − Replace stem cap and tighten it firmly. Tighten finger

tight, then tighten an additional 1/6 turn.

To Close Service Valve:

1 − Remove stem cap with an adjustable wrench.
2 − Using service wrench and hex head extension, turn

stem clockwise to seat valve. Tighten it firmly.

NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.

3 − Replace stem cap. Tighten finger tight, then tighten an

additional 1/6 turn.

Vapor Line (Ball Type) Valve

Vapor line 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 valve is illustrated in figure 14.
The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−
free seal.

Page 12

Liquid Service Valve (Valve Open)

Insert Hex

Wrench Here

Field Side

Schrader

Valve

Service Port

Cap

Service Port

Liquid Service Valve (Valve Closed)

Field Side

Service

Port

Service Port

Cap

Schrader Valve Open

To Line Set When Valve Is

Closed (Front Seated)

Vapor Line (Ball Type) Service Valve

Use Adjustable Wrench

To open: rotate stem counter-clockwise 90°.

To close: rotate stem clockwise 90°.

Schrader

valve

service

port

field side

(shown open)

Figure 13

(Valve Open)

service port

cap

ball

Figure 14

Stem Cap

Unit Side

Stem Cap

Insert Hex

Wrench Here

(Valve Front

Seated)

Unit Side

unit side

stem

stem cap

Leak Testing

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.

WARNING

Refrigerant can be harmful if it is inhaled. Refriger­ant must be used and recovered responsibly.

Failure to follow this warning may result in personal
injury or death.

WARNING

Danger of explosion: Can cause
equipment damage, injury or death.
Never use oxygen to pressurize a re­frigeration or air conditioning system.
Oxygen will explode on contact with
oil and could cause personal injury.

WARNING

Danger of explosion: Can cause equipment damage,
injury or death. When using a high pressure gas
such as dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9 to 13.8
kPa).

Using an Electronic Leak Detector

1 − Connect a cylinder of R410A to the center port of the

manifold gauge set.

2 − With both manifold valves closed, open the valve on

the R410A cylinder (vapor only).

3 − Open the high pressure side of the manifold to allow

the R410A into the line set and indoor unit. Weigh in a
trace amount of R410A . [A trace amount is a maximum
of 2 ounces (57 g) or 3 pounds (31 kPa) pressure.]
Close the valve on the R410A cylinder and the valve
on the high pressure side of the manifold gauge set.
Disconnect the R410A cylinder.

4 − Connect a cylinder of nitrogen with a pressure regulat-

ing 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 pres-

sure 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 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.

Page 13

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 nitrogen and R410A
mixture. Correct any leaks and recheck.

IMPORTANT

Leak detector must be capable of sensing HFC re­frigerant.

Evacuation

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.

IMPORTANT

Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
that reads from 50 microns to at least 10,000 microns.

1 − Connect the 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.

3 − Connect the vacuum pump (with vacuum gauge) to the

center port of the manifold gauge set.

4 − Open both manifold valves and start 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.

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 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.

WARNING

Danger of Equipment Damage.
Avoid deep vacuum operation. Do not use com­pressors to evacuate a system.
Extremely low vacuums can cause internal arcing
and compressor failure.
Damage caused by deep vacuum operation will
void warranty.

7 − Shut off the nitrogen cylinder and remove the manifold

gauge hose from the cylinder. Open the manifold
gauge valves to release the nitrogen from the line set
and indoor unit.

8 − 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.

9 − 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 R410A
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 R410A cylinder and remove the manifold
gauge set.

Start−Up

IMPORTANT

If unit is equipped with crankcase heater, it should be
energized 24 hours before unit start−up to prevent
compressor damage as a result of slugging.

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 tight-

en 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.

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.

Page 14

Charging

This system is charged with R410A refrigerant which oper­ates at much higher pressures than R22. The check/ex­pansion valve provided with the unit is approved for use
with R410A. Do not replace it with a valve designed for use
with R22. This unit is NOT approved for use with coils which
include metering orifices or capillary tubes.

Processing Procedure

The unit is factory−charged with the amount of R410A 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 2 for refrigerant charge adjustment.

Table 2

Liquid Line Set

Diameter

3/8 in.

(10 mm)

*If line length is greater than 15 ft. (4.6 m), add this amount.
If line length is less than 15 ft. (4.6 m), subtract this amount.

Oz. per 5 ft. (grams per 1.5 m) adjust

from 15 ft. (4.6 m) line set*

3 ounces per 5 feet

(85g per 1.5 m)

IMPORTANT

Mineral oils are not compatible with R410A. If oil
must be added, it must be a polyol ester oil.

The compressor is charged with sufficient polyol ester
oil for line set lengths up to 50 feet (15.2 m). Do not add
any more than 7 oz. of oil.If oil must be added to the
compressor in the field, Copeland has approved Mobil
EALt Arctic 22CC and ICI EMKARATEt RL32CF.

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 deter-

mined by the unit’s refrigerant metering device and the out­door ambient temperature.

Measure the liquid line temperature and the outdoor ambi­ent temperature as outlined below:

1 − Close manifold gauge set valves. Connect manifold

gauge set to service valves as shown in figure 16:
 low pressure gauge to vapor valve service port
 high pressure gauge to liquid valve service port

Connect the center manifold hose to an upright cylin­der of R410A .

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 − Use a digital thermometer to record the outdoor ambi-

ent temperature.

4 − When the heating demand has been satisfied, switch

the thermostat to cooling mode with a set point of 68F
(20C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.

5 − The outdoor temperature will determine which charg-

ing method to use. Proceed with the appropriate charg­ing procedure.

Weighing in the Charge TXV Systems –

Outdoor Temp < 65F (18C)

If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, the refrigerant charge should be
weighed into the unit. Do this after any leaks have been re­paired.

1 − Recover the refrigerant from the unit.

2 − Conduct a leak check, then evacuate as previously

outlined.

3 − Weigh in the unit nameplate charge.

If weighing facilities are not available or if you are charging
the unit during warm weather, follow one of the other proce­dures outlined below.

Subcooling Method

Outdoor Temp. < 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 15.

Blocking Outdoor Coil

Outdoor coil should be

blocked one side

at a time with cardboard

or plastic sheet until proper

testing pressures

are reached.

cardboard or
plastic sheet

Figure 15

1 − With the manifold gauge hose still on the liquid service

port and the unit operating stably, use a digital ther-

mometer to record the liquid line temperature.
2 − At the same time, record the liquid line pressure reading.
3 − Use a temperature/pressure chart for R410A to deter-

mine the saturation temperature for the liquid line pres-

sure reading. See table 6.

4 − Subtract the liquid line temperature from the saturation

temperature (according to the chart) to determine sub-

cooling. (Saturation temperature − Liquid line tem-

perature = Subcooling)

5 − Compare the subcooling value with those in table 3. If

subcooling is greater than shown, recover some refrig-

erant. If subcooling is less than shown, add some re-

frigerant. Be aware of the R410A refrigerant cylinder. It

Page 15

will be light maroon−colored. Refrigerant should be
added through the vapor line valve in the liquid state.

Some R410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from
the bottom of the cylinder without turning the cyl­inder upside−down. The cylinder will be marked if it
is equipped with a dip tube.

Table 3

Subcooling Values for Charging

Model Number

HPXA15−024 5 ± 1 (2.8 ± .5)

HPXA15−030 8± 1 (7.4 ± .5)

HPXA15−036 5.5 ± 1 (3 ± .5)

HPXA15−042 4.5 ± 1 (2.5 ± .5)

HPXA15−048 2.5 ± 1 (1.4 ± .5)

HPXA15−060 6 ± 1 (3.3 ± .5)

Conversion Temp. − Liquid Line Temp. °F (°C)

Subcooling Values

Charging Using Normal Operating Pressures

and the Approach Method

Outdoor Temp. >

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 using a digital

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

table 5, Normal Operating Pressures." Minor varia­tions in these pressures may be expected due to differ­ences in installations. Significant differences could
mean that the system is not properly charged or that a
problem exists with some component in the system.

65F (18C)

Pressures higher than those listed indicate that the

system is overcharged. Pressures lower than those

listed indicate that the system is undercharged. Verify

adjusted charge using the approach method.

Approach Method

4 − Use the same digital thermometer used to check out-

door ambient temperature to check liquid line tempera-

ture. Verify the unit charge using the approach method.
5 − The difference between the ambient and liquid temper-

atures should match values given in table 4. If the val-

ues don’t agree with the those in table 4, add refriger-

ant to lower the approach temperature or recover

refrigerant from the system to increase the approach

temperature.

Table 4

Approach Values for Charging

Model Number

HPXA15−024 13 ± 1 (7.2 ± .5)

HPXA15−030 7 ± 1 (3.9 ± .5)

HPXA15−036 11 ± 1 (6.1 ± .5)

HPXA15−042 12.5 ± 1 (6.9 ± .5)

HPXA15−048 10 ± 1 (5.6 ± .5)

HPXA15−060 11.5 ± 1 (6.5 ± .5)

Liquid Line Temp. − Outdoor Ambient °F (°C)

Approach Temperature

IMPORTANT

Use table 5 as a general guide when performing
maintenance checks. This is not a procedure for
charging the unit (Refer to Charging/Checking
Charge section). Minor variations in these pressures
may be expected due to differences in installations.
Significant differences could mean that the system
is not properly charged or that a problem exists with
some component in the system.

Page 16

DEFROST THERMOSTAT

)

)

EXPANSION/

CHECK VALVE

LOW

PRESSURE

HIGH

PRESSURE

HPXA15 Cooling Cycle

(Showing Gauge Manifold Connections)

OUTDOOR UNIT

DISTRIBUTOR

REVERSING VALVE

BIFLOW

FILTER /

DRIER

MUFFLER

OUTDOOR

COIL

NOTE − ARROWS INDICATE

DIRECTION OF REFRIGERANT

FLOW

INDOOR UNIT

GAUGE MANIFOLD

TO

R410A

DRUM

LIQUID

LINE

SERVICE

PORT

COMPRESSOR

NOTE−Use gauge ports on vapor line valve and liquid valve for evacuating refrigerant lines

VAPOR

SERVICE

PORT

VAPOR

LINE

VALV E

EXPANSION/CHECK

VALV E

INDOOR

COIL

and indoor coil. Use vapor gauge port to measure vapor pressure during charging.

Figure 16

Table 5

Normal Operating Pressures

(Liquid ±10 and Vapor ±5 psig)

Cooling Operation

Outdoor Coil

Entering Air

Temp. °F (°C

65 (18.3) 252 131 233 141 216 136 240 133 228 137 231 124

75 (23.9) 291 133 272 142 276 138 281 135 265 139 269 126

85 (29.4) 337 135 314 143 298 139 325 137 304 141 315 127

95 (35.0) 371 140 360 146 359 141 372 138 348 142 370 133

105 (40.6) 421 142 413 148 400 143 428 142 405 145 415 136

Outdoor Coil

Entering Air

Temp. °F (°C

20 (−6.6) 288 60 270 67 234 62 340 65 313 60 245 55

30 (−1.1) 306 75 297 84 257 80 350 72 330 73 287 66

40 (4.4) 325 90 325 100 318 93 353 83 346 87 332 82

50 (10.0) 344 105 353 11 7 322 103 358 101 366 101 347 99

HPXA15−024 HPXA15−030 HPXA15−036 HPXA15−042 HPXA15−048 HPXA15−060

Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor

Heating Operation

HPXA15−024 HPXA15−030 HPXA15−036 HPXA15−042 HPXA15−048 HPXA15−060

Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor

Page 17

Table 6

R410A Temperature/Pressure Chart

Temperature°FPressure

Psig

32 100.8 63 178.5 94 290.8 125 445.9
33 102.9 64 181.6 95 295.1 126 451.8

34 105.0 65 184.3 96 299.4 127 457.6

35 107.1 66 187.7 97 303.8 128 463.5
36 109.2 67 190.9 98 308.2 129 469.5

37 111.4 68 194.1 99 312.7 130 475.6

38 113.6 69 197.3 100 317.2 131 481.6

39 115.8 70 200.6 101 321.8 132 487.8
40 118.0 71 203.9 102 326.4 133 494.0

41 120.3 72 207.2 103 331.0 134 500.2

42 122.6 73 210.6 104 335.7 135 506.5
43 125.0 74 214.0 105 340.5 136 512.9

44 127.3 75 217.4 106 345.3 137 519.3

45 129.7 76 220.9 107 350.1 138 525.8

46 132.2 77 224.4 108 355.0 139 532.4
47 134.6 78 228.0 109 360.0 140 539.0

48 137.1 79 231.6 110 365.0 141 545.6

49 139.6 80 235.3 111 370.0 142 552.3

50 142.2 81 239.0 112 375.1 143 559.1
51 144.8 82 242.7 113 380.2 144 565.9

52 147.4 83 246.5 114 385.4 145 572.8

53 150.1 84 250.3 115 390.7 146 579.8

54 152.8 85 254.1 116 396.0 147 586.8
55 155.5 86 258.0 117 401.3 148 593.8

56 158.2 87 262.0 118 406.7 149 601.0

57 161.0 88 266.0 119 412.2 150 608.1

58 163.9 89 270.0 120 417.7 151 615.4
59 166.7 90 274.1 121 423.2 152 622.7

60 169.6 91 278.2 122 428.8 153 630.1

61 172.6 92 282.3 123 434.5 154 637.5

62 195.5 93 286.5 124 440.2 155 645.0

Temperature°FPressure

Psig

Temperature°FPressure

Psig

Temperature°FPressure

Psig

Page 18

System Operation

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.

Filter Drier

The unit is equipped with a large−capacity biflow filter drier
which keeps the system clean and dry. If replacement is
necessary, order another of like design and capacity. The
replacement filter drier must be suitable for use with R410A
refrigerant.

Thermostat Operation

Some outdoor 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.

Emergency Heat (Amber Light)

An emergency heat function is designed into some room ther­mostats. This feature is applicable when isolation of 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.

High Pressure Switch

The HPXA15 is equipped with an auto−reset high pressure
switch which is located on the liquid line. The normally
closed switch opens the compressor circuit when dis­charge pressure rises above 640 + 10 psig (4412 + 69
kPa). The switch automatically closes when discharge
pressure falls below 448 + 10 psig (3089 + 69 kPa).

Defrost System

The defrost system includes two components:

 a defrost thermostat
 a defrost control

Defrost Thermostat

The defrost thermostat is located on the liquid line be­tween the check/expansion valve and the distributor.
When the defrost thermostat senses 42°F (5.5°C) or cool­er, its contacts close and send a signal to the defrost con­trol board to start the defrost timing. It also terminates de­frost when the liquid line warms up to 70°F (21°C).

Defrost Control

The defrost control board includes the combined func­tions of a time/temperature defrost control, defrost
relay, time delay, diagnostic LEDs, and a terminal strip
for field wiring connections. See figure 17.

The control provides automatic switching from normal
heating operation to defrost mode and back. During com­pressor cycle (call for defrost), the control accumulates
compressor run times at 30, 60, or 90 minute field adjust­able intervals. If the defrost thermostat is closed when the
selected compressor run time interval ends, the defrost
relay is energized and defrost begins.

Defrost Control Timing Pins

Each timing pin selection provides a different accumu­lated compressor run time period during one thermostat
run cycle. This time period must occur before a defrost
cycle is initiated. The defrost interval can be adjusted to
30 (T1), 60 (T2), or 90 (T3) minutes. See figure 17. The
defrost timing jumper is factory−installed to provide a
90−minute defrost interval. If the timing selector jumper is
not in place, the control defaults to a 90−minute defrost
interval. The maximum defrost period is 14 minutes and
cannot be adjusted.

A TEST option is provided for troubleshooting. The TEST

mode may be started any time the unit is in the heating
mode and the defrost thermostat is closed or jump­ered. If the jumper is in the TEST position at power-up, the

control will ignore the test pins. When the jumper is placed
across the TEST pins for two seconds, the control will enter
the defrost mode. If the jumper is removed before an addi­tional 5−second period has elapsed (7 seconds total), the
unit will remain in defrost mode until the defrost thermostat
opens or 14 minutes have passed. If the jumper is not re­moved until after the additional 5−second period has
elapsed, the defrost will terminate and the test option will
not function again until the jumper is removed and reap­plied.

Time Delay

The timed−off delay is five minutes long. The delay helps
protect the compressor from short−cycling in case the power
to the unit is interrupted or a pressure switch opens. The
delay is bypassed by placing the timer select jumper across
the TEST pins for 0.5 seconds.

Pressure Switch Circuits

The defrost control includes two pressure switch circuits.
The high pressure switch (S4) is factory−connected to the
board’s HI PS terminals. The board also includes LO PS ter­minals to accommodate the addition of a field−provided low
pressure or loss of charge pressure switch. See figure 17.
This feature is available on all units.

During a single demand cycle, the defrost control will lock
out the unit after the third time that the circuit is interrupted
by any pressure switch that is wired to the control board. In
addition, the diagnostic LEDs will indicate a locked out

Page 19

pressure switch after the third occurrence of an open pres­sure switch. See table 7. The unit will remain locked out un­til power is broken then remade to the control or until the
jumper is applied to the TEST pins for 0.5 seconds.

NOTE − The defrost control board ignores input from the
low pressure switch terminals during the TEST mode, dur­ing the defrost cycle, during the 90−second start−up period,
and for the first 90 seconds each time the reversing valve
switches heat/cool modes. If the TEST pins are jumpered

and the 5−minute delay is being bypassed, the LO PS
terminal signal is not ignored during the 90−second
start−up period.

Ambient Thermistor & Service Light Connection

The defrost control board provides terminal connections
for the ambient thermistor and a service light. The thermis­tor compensates for changes in ambient temperature

which might cause thermostat droop. The service light
thermostat provides a signal which activates the room ther­mostat service light during periods of inefficient operation.

Diagnostic LEDs

The defrost board uses two LEDs for diagnostics. The
LEDs flash a specific sequence according to the diagnosis.

Table 7

Defrost Control Board Diagnostic LED

Mode LED 1 LED 2

Normal operation /
power to board

Board failure or no power Off Off

Board failure On On

High pressure switch open Flash On

Low pressure switch open On Flash

Pressure switch lockout On Off

Anti−short−cycle /
5−minute delay

Synchronized
Flash with LED 2

Alternating Flash
with LED 2

Synchronized
Flash with LED 1

Alternating Flash
with LED 1

Defrost Control Board

PRESSURE SWITCH

WIRING CONNECTIONS

High

Pressure

Switch

(Factory−wired)

Optional

Pressure

Switch
(Field−provided
and installed −−

jumper removed)

S4

S5

HIGH PRESSURE

SWITCH

TERMINALS

OPTIONAL

PRESSURE

SWITCH

TERMINALS

(Remove factory−

installed jumper

to install

pressure switch.)

DEFROST
INTERVAL

TIMING PINS

DIAGNOSTIC

LEDs

SERVICE

LIGHT

TERMINALS

AMBIENT

THERMISTOR

TERMINALS

24V

TERMINAL

STRIP

Figure 17

Page 20

Maintenance

WARNING

Electric shock hazard. Can cause inju­ry or death. Before attempting to per­form any service or maintenance, turn
the electrical power to unit OFF at dis­connect switch(es). Unit may have
multiple power supplies.

Maintenance and service must be performed by a quali­fied installer or service agency. At the beginning of each
cooling or heating season, the system should be checked
as follows:

Outdoor Unit

1 − Clean and inspect outdoor coil (may be flushed with a

water hose). Ensure power is off before cleaning.

2 − Outdoor unit fan motor is prelubricated and sealed. No

further lubrication is needed.

3 − Visually inspect all connecting lines, joints and coils for

evidence of oil leaks.
4 − Check all wiring for loose connections.
5 − Check for correct voltage at unit (unit operating).
6 − Check amp−draw on outdoor fan motor.

Unit nameplate_______Actual_______.
7 − Inspect drain holes in coil compartment base and

clean if necessary.

NOTE − If owner complains of insufficient cooling, the unit
should be gauged and refrigerant charge checked. Refer to
section on refrigerant charging in this instruction.

Indoor Coil

1 − Clean coil if necessary.

2 − Check connecting lines, joints and coil for evidence of

oil leaks.

3 − Check condensate line and clean if necessary.

Indoor Unit

1 − Clean or change filters.

2 - Lennox blower motors are prelubricated and permanent-

ly sealed. No more lubrication is needed.

3 − 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.

4 − Belt Drive Blowers − Check belt for wear and proper

tension.

5 − Check all wiring for loose connections.

6 − Check for correct voltage at unit.

7 − Check amp−draw on blower motor.

Motor nameplate_______Actual_______.

Optional Accessories

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 Switc Kit
 Compressor Monitor
 Compressor Crankcase Heater
 Hail Guards
 Mounting Bases
 Timed Off Control
 Stand−off Kit
 Sound Cover
 Low Ambient Kit
 Monitor Kit

HPXA15 Check Points

Job Name

Job Location
Installer

Unit Model No.
Nameplate Voltage

Rated Load Ampacity
Maximum Fuse or Circuit Breaker
Electrical Connections Tight?

Indoor Blower RPM

Cooling

Liquid Line Pressure

Heating

Liquid Line Pressure
Refrigerant Lines:

Service Valves Fully Opened?

Sequence of Operation

Heating Correct Cooling Correct

Leak Checked?

S.P. Drop Over Indoor (Dry)

Start−up and Performance Check List

Job No.

City

City

Serial No.

Compressor

Indoor Filter Clean?

Vapor Pressure

Vapor Pressure

Properly Insulated?

Service Valve Caps Tight?

Page 21

Voltage With Compressor Operating

Calibrated? Properly Set? Level?

Outdoor Fan

Outdoor Coil Entering Air Temp.

Refrigerant Charge Checked?

Refrigerant Charge Checked?

Date

State

State

Service Technician

Supply Voltage (Unit Off)

Outdoor Fan Checked?

Thermostat