Lennox HPXA12 Series, HPXA12-018, HPXA12-024, HPXA12-030, HPXA12-036 Unit Information

Corp. 0208−L3

Service Literature

Revised 09−2004

HPXA12 SERIES UNITS

The HPXA12 is a high efficiency residential split−system
heat pump unit, which features a scroll compressor and
R410A refrigerant. HPXA12 units are available in sizes
ranging from 1 1/2 through 5 tons. The series is designed
for use with an expansion valve only (approved for use with
R410A) in the indoor unit.This manual is divided into sec­tions which discuss the major components, refrigerant sys­tem, charging procedure, maintenance and operation se­quence.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are
subject to change.

IMPORTANT

Operating pressures of this R410A unit are higher
than pressures in R22 units. Always use service
equipment rated for R410A.

HPXA12

WARNING

Warranty will be voided if covered equipment is re­moved from original installation site. Warranty will
not cover damage or defect resulting from:
Flood, wind, lightning, or installation and opera­tion in a corrosive atmosphere (chlorine, fluorine,
salt, recycled waste water, urine, fertilizers, or oth­er damaging chemicals).

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.

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.

TABLE OF CONTENTS

General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Specifications / Electrical 2. . . . . . . . . . . . . . . . . . . . . . . .

I Unit Information 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

II Unit Components 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

III Refrigerant System 13. . . . . . . . . . . . . . . . . . . . . . . . . .

IV Charging 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

V Service and Recovery 19. . . . . . . . . . . . . . . . . . . . . . . .

VI Maintenance 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VII Wiring Diagram and Operating Sequence 20. . . . . .

Page 1

©2002 Lennox Industries Inc.

SPECIFICATIONS single phase

Fan

Net face area

Kit

M

General
Data

Connections
(sweat)

Refrigerant (R410A) furnished 7 lbs. 5 oz. (3.31 kg) 6 lbs. 12 oz. (3.06

Outdoor
Coil
Fan

Outdoor
Coil

Shipping Data lbs. (kg) 1 package 160 (73) 160 (73) 176 (80) 181 (82)

Diameter − in. (mm) & no. of blades

Net face area

sq. ft. (m2)

Tube diameter − in. (mm) & no. of rows

Nominal Tonnage (kW) 1.5 (5.3) 2 (7.0) 2.5 (8.8) 3 (10.6)

Liquid line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Vapor line o.d. − in. (mm) 3/4 (19.1) 3/4 (19.1) 3/4 (19.1) 7/8 (22.2)

Model No. HPXA12−018 HPXA12−024 HPXA12−030 HPXA12−036

Motor hp (W)

Cfm (L/s)

Rpm

Watts

Outer coil

Inner coil

Fins per inch (m)

18 (457) − 3

1/6 (124)

2500 (1180)

1100

200

15.21 (1.41)

5.44 (0.51)

5/16 (8) − 1.37

18 (709)

kg)

18 (457) − 3 18 (457) − 4 18 (457) − 4

1/6 (124) 1/6 (124) 1/6 (124)

2500 (1180) 2450 (1155) 2450 (1155)

1100 1100 1100

200 200 200

15.21 (1.41) 15.21 (1.41) 15.21 (1.41)

5.44 (0.51) 14.50 (1.35) 14.50 (1.35)

5/16 (8) − 1.37 5/16 (8) − 2 5/16 (8) − 2

18 (709) 18 (709) 18 (709)

7 lbs. 12 oz. (3.51

kg)

8 lbs. 15 oz. (4.1 kg)

OPTIONAL ACCESSORIES − MUST BE ORDERED EXTRA

Compressor Monitor (Canada Only) 45F08 45F08 45F08 45F08

Hail Guards 17L73 17L73 17L73 17L73

Mild Ambient Kit (LB-101122) 32M08 32M08 32M08 32M08

Monitor Kit (Canada Only) 76F53 76F53 76F53 76F53

Outdoor
Thermostat
Kit

Plastic

ounting

Base

Refrigerant
Line Set

Unit Stand-Off Kit 94J45 94J45 94J45 94J45

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
Refrigerant charge is sufficient for 15 ft. (4.5 m) length line set.

NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage

Part No. − Catalog Number MB2-S (69J06) MB2-S (69J06) MB2-S (69J06) MB2-S (69J06)

Suction/Vapor Line o.d. − in. (mm) 3/4 (19) 3/4 (19) 3/4 (19) 7/8 (22.2)

Liquid Line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Thermostat 56A87 56A87 56A87 56A87

Mounting Box − US 31461 31461 31461 31461

Canada 33A29 33A29 33A29 33A29

Net Weight 6 lbs. (3 kg) 6 lbs. (3 kg) 6 lbs. (3 kg) 6 lbs. (3 kg)

30 ft. (9 m) length L15−41−30 L15−41−30 L15−41−30 L15−65−30

40 ft. (12 m) length L15−41−40 L15−41−40 L15−41−40 L15−65−40

50 ft. (15 m) length L15−41−50 L15−41−50 L15−41−50 L15−65−50

Page 2

SPECIFICATIONS single phase Cont.

Fan

Net face area

Kit

M

g

p

General
Data

Connections
(sweat)

Refrigerant (R410A) furnished 9 lb. 2 oz. (4.13 kg) 11 lbs. 5 oz. (5.12 kg) 11 lbs. 3 oz. (5.06 kg)

Outdoor
Coil

Outdoor
Coil

Shipping Data lbs. (kg) 1 package 190 (86) 244 (111) 244 (111)

Diameter − in. (mm) & no. of blades 18 (457) − 4 22 (559) − 4 22 (559) − 4

Net face area

sq. ft. (m2)

Tube diameter − in. (mm) & no. of rows 5/16 (8) − 2 5/16 (8) − 2 5/16 (8) − 2

Nominal Tonnage (kW) 3.5 (12.3) 4 (14.1) 5 (17.6)

Liquid line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Vapor line o.d. − in. (mm) 7/8 (22.2) 7/8 (22.2) 1−1/8 (28.6)

Model No. HPXA12−042 HPXA12−048 HPXA12−060

Motor hp (W) 1/3 (249) 1/3 (249) 1/3 (249)

Cfm (L/s) 2930 (1385) 3890 (1835) 3890 (1835)

Rpm 1100 1085 1085

Watts 310 375 375

Outer coil 15.21 (1.41) 21.11 (1.96) 21.11 (1.96)

Inner coil 14.50 (1.35) 20.31 (1.89) 20.31 (1.89)

Fins per inch (m) 22 (860) 22 (860) 22 (860)

OPTIONAL ACCESSORIES − MUST BE ORDERED EXTRA

Compressor Monitor (Canada Only) 45F08 45F08 45F08

Hail Guards 17L73 17L74 17L74

Mild Ambient Kit (LB-101122) 32M08 32M08 32M08

Monitor Kit (Canada Only) 76F53 76F53 76F53

Outdoor
Thermostat

Plastic

ounting

Base

Refrigerant
Line Set

Unit Stand-Off Kit 94J45 94J45 94J45

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
Refrigerant charge is sufficient for 20 ft. (6.1 m) length line set.

NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage

Part No. − Catalog Number MB2-S (69J06) MB2-L (69J07) MB2-L (69J07)

Suction/Vapor Line o.d. − in. (mm) 7/8 (22.2) 7/8 (22.2) 1−1/8 (28.5)

Liquid Line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Thermostat 56A87 56A87 56A87

Mounting Box − US 31461 31461 31461

Canada 33A29 33A29 33A29

Net Weight 6 lbs. (3 kg) 15 lbs. (7 kg) 15 lbs. (7 kg)

30 ft. (9 m) length L15−65−30 L15−65−30 Field Fabricate

40 ft. (12 m) length L15−65−40 L15−65−40 Field Fabricate

50 ft. (15 m) length L15−65−50 L15−65−50 Field Fabricate

ELECTRICAL DATA

Model No. HPXA12−018 HPXA12−024 HPXA12−030 HPXA12−036 HPXA12−042 HPXA12−048 HPXA12−060

Line voltage data − 60 hz − 1 phase 208/230v 208/230v 208/230v 208/230v 208/230v 208/230v 208/230v

Recommended maximum fuse or
circuit breaker size (amps)

{Minimum circuit ampacity 14.0 18.0 20.0 20.4 25.9 30.8 36.4

Compressor

Outdoor Coil

Fan Motor

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
NOTE  Extremes of operating range are plus 10% and minus 5% of line voltage.

Rated load amps 10.3 13.5 15.1 15.4 19.2 23.1 27.6

Power factor .98 .98 .98 .98 .99 .99 .99

Locked rotor amps 51 61 72.5 83 104 134 158

Full load amps 1.1 1.1 1.1 1.1 1.9 1.9 1.9

Locked rotor amps 1.9 1.9 1.9 1.9 4.1 4.1 4.1

20 30 35 35 45 50 60

Page 3

SPECIFICATIONS three phase

Fan

Net face area

p

Kit

g

g

General
Data

Connections
(sweat)

1

Refrigerant (R410A) furnished 8 lbs. 15 oz. (4.1 kg) 11 lbs. 5 oz. (5.1 kg) 11 lbs. 3 oz. (5.1 kg)

Outdoor

Diameter − in. (mm) & no. of blades 18 (457) − 4 22 (559) − 4 22 (559) − 4

Nominal Tonnage (kW) 3 (10.6) 4 (14.1) 5 (17.6)

Liquid line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Vapor line o.d. − in. (mm) 7/8 (22.2) 7/8 (22.2) 1−1/8 (28.6)

Coil

Outdoor
Coil

Net face area

sq. ft. (m2)

Tube diameter − in. (mm) & no. of rows 5/16 (8) − 2 5/16 (8) − 2 5/16 (8) − 2

Shipping Data 1 package − lbs. (kg) 181 (82) 244 (111) 244 (111)

ELECTRICAL DATA

Line voltage data − 60 hz − 3 phase 208/230V 460V 208/230V 460V 208/230V 460V

2

Maximum overcurrent protection (amps) 25 10 35 15 40 20

3

Minimum circuit ampacity 15.4 6.9 21.9 9.8 24.5 12.2

Compressor

Locked Rotor amps 77 35 91 46 137 62

Outdoor Coil

Fan Motor

Locked Rotor Amps 2.3 1 4.1 2.1 4.1 2.1

OPTIONAL ACCESSORIES − MUST BE ORDERED EXTRA

Compressor Low Ambient Cut−Off 45F08 45F08 45F08

Compressor Sound Cover 69J03 69J03 69J03

Compressor Crankcase Heater 67K90 67K89 Factory Installed Factory Installed

Freezestat

Hail Guards 17L73 17L74 17L74

Low Ambient Kit 54M89 54M89 54M89

Mild Weather Kit 33M07 33M07 33M07

Monitor Kit − Service Light 76F53 76F53 76F53

Outdoor
Thermostat
Kit

Mounting
Base

Refrigerant
Line Set

Unit Stand-Off Kit 94J45 94J45 94J45

NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage.

1

Refrigerant charge is sufficient for 15 ft. (4.6 m) length line set.

2

HACR tyoe circuit breaker or fuse.

3

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Mounting Box − US 31461 31461 31461

15 ft. (4.6 m) length L15−65−15 L15−65−15 Field Fabricate

40 ft. (12 m) length L15−65−40 L15−65−40 Field Fabricate

50 ft. (15 m) length L15−65−50 L15−65−50 Field Fabricate

Model No. HPXA12−036 HPXA12−048 HPXA12−060

Motor hp (W) 1/6 (124) 1/3 (249) 1/3 (249)

Cfm (L/s) 2450 (1155) 3890 (1835) 3890 (1835)

Rpm 1100 1085 1085

Watts 200 375 375

Outer coil 15.21 (1.41) 21.11 (1.96) 21.11 (1.96)

Inner coil 14.50 (1.35) 20.31 (1.89) 20.31 (1.89)

Fins per inch (m) 18 (709) 22 (860) 22 (860)

Model No. HPXA12−036

Rated load amps

−233

11.5 5.1 16 7.1 18.1 9

HPXA12−036

−463

HPXA12−048

−233

HPXA12−048

−463

HPXA12−060

−233

HPXA12−060

Power Factor .98 .98 .99 .99 .99 .99

Full load amps

1 .55 1.9 .9 1.9 .9

3/8 in. tubing 93G35 93G35 93G35

1/2 in. tubing 39H29 39H29 39H29

5/8 in. tubing 50A93 50A93 50A93

Thermostat 56A87 56A87 56A87

Canada 33A09 33A09 33A09

Model (Catalog) No. MB2-S (69J06) MB2-L (69J07) MB2-L (69J07)

Net Weight 6 lbs. (3 kg) 15 lbs. (7 kg) 15 lbs. (7 kg)

30 ft. (9 m) length L15−65−30 L15−65−30 Field Fabricate

−463

Page 4

I − UNIT INFORMATION

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic
components. Take precautions during unit instal­lation and service to protect the unit’s electronic
controls. Precautions will help to avoid control
exposure to electrostatic discharge by putting
the unit, the control and the technician at the
same electrostatic potential. Neutralize electro­static charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.

All major components (indoor blower and coil) must be
matched according to Lennox recommendations for the
compressor to be covered under warranty. Refer to the En­gineering Handbook for approved system matchups. A
missapplied system will cause erratic operation and can re­sult in early compressor failure.

A − Control Box (Figures 2 and 3)

HPXA12 units are not equipped with a 24V transformer. All
24 VAC controls are powered by the indoor unit. Refer to
wiring diagram.

SINGLE PHASE UNIT CONTROL BOX

DUAL CAPACITOR

(C12)

COMPRESSOR

CONTACTOR

(K1)

DEFROST

GROUNDING

LUG

FIGURE 2

CONTROL

(A108)

IMPORTANT

This unit must be matched with an indoor coil as
specified in Lennox’ Engineering Handbook.

II − UNIT COMPONENTS

Unit components are illustrated in figure 1.

OUTDOOR

FAN/MOTOR

HPXA12 UNIT COMPONENTS

CONTROL

BOX

SUCTION

MUFFLER

REVERSING

VALV E

THREE PHASE UNIT CONTROL BOX

RUN CAPACITOR

(C1)

OUTDOOR FAN

RELAY (K10)

460 VOLTAGE

COMPRESSOR

CONTACTOR

(K1)

GROUNDING

LUG

ONLY

DEFROST

CONTROL

(A108)

FIGURE 3

Electrical openings are provided under the control box cov­er. Field thermostat wiring is made to a 24V terminal strip
located on the defrost control board located in the control
box. See figure 4.

24V THERMOSTAT TERMINAL STRIP

COMPRESSOR

BI-FLOW

FILTER DRIER

FIGURE 1

CHECK/EXPANSION

VALV E

Page 5

Y2

CRW1OY1L

FIGURE 4

1 − Compressor Contactor K1

The compressor is energized by a contactor located in the
control box. See figure 2. Single−pole contactors are used
in single−phase HPXA12 series units and three pole con­tactors are used in HPXA12 three−phase units. K1 is ener­gized through the control board by the indoor thermostat
terminal Y1 (24V) when thermostat demand is present.

DANGER

Electric Shock Hazard.
May cause injury or death.

Line voltage is present at all compo­nents when unit is not in operation on
units with single pole contactors.
Disconnect all remote electrical power
supplies before opening unit panel.
Unit may have multiple power supplies.

2 − Outdoor Fan Relay K10 (460V units only)

Outdoor fan relay K10, used in 460V units only, is a SPST
normally open relay. K10 is energized by contactor K1
which in turn energizes outdoor fan B4 in response to ther­mostat demand.

3 − Run Capacitor C1 (three phase only)

The fan in all three−phase units uses a single−phase perma­nent split capacitor motor. A single capacitor C1 is used for
the fan motor. C1 is located inside the control box. See fig­ure 3. Fan motor nameplate will have capacitor ratings.

The demand defrost board uses basic differential temper­ature means to detect degradation of system performance
due to ice build−up on the outdoor coil. Further, the control­ler uses self−calibrating" principles to calibrate itself when
the system starts and after each time the system defrosts.
The control board has defrost relays, anti−short cycle
timed−off control, pressure switch/safety control, 3−strike
lockout circuit, field test pins, ambient and coil tempera­ture sensors, field selectable termination temperature and
a field low voltage connection terminal strip.
The control monitors ambient temperature, outdoor coil
temperature and total run time to determine when a de­frost cycle is required. Two temperature probes are per­manently attached to the control. 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. On HPXA12−018 &

−024 the sensor should located on the 4th hairpin bend
from the bottom. HPXA12−030 through −060 units the sen­sor should located on the 6th hairpin bend from the bot­tom. See figure 5.

NOTE − The logic of the Demand Defrost Board provides
accurate performance measurements of the system as
FROST accumulates on the outdoor coil. This will translate
into longer running time in the heating mode with FROST
accumulations on the outdoor coil before the board initiates
any defrost cycles.

COIL SENSOR LOCATION

4 − Dual Capacitor C12

The compressor and fan in single phase HPXA12 series units
use permanent split capacitor motors. The capacitor is located
inside the unit control box (see figure 2). A single dual" capaci­tor (C12) is used for both the fan motor and the compressor
(see unit wiring diagram). The fan side and the compressor
side of the capacitor have different MFD ratings. See side of
capacitor for ratings.

5 − Demand Defrost System

Boards 60L3901, 46M8201, 56M8501

The HPXA12 will be equipped with one of three model de­frost boards. Differences are minimal:

Three strike lock out feature (60L3901)
 Five strike out feature (46M8201, 56M8501)
 Terminal T" for ambient sensor (60L3901)
 Terminal Y2" for 2nd stage thermostat input (46M8201,

56M8501).
 DELAY" pins (56M8501)

On HPXA12−030 /

On HPXA12−018,

−024 units,clip the coil
sensor clip on the 4th
bend from the bottom

The temperature probes cannot be detached from the con­trol. The control and the attached probes MUST be re­placed as a unit. Do not attempt to cut or splice probe wires.

−060 units,clip the coil
sensor clip on the 6th
bend from the bottom

FIGURE 5

Diagnostic LEDs

The defrost board uses two LEDs for diagnostics. The
LEDs flash a specific sequence according to the condition.
See table 1.

Page 6

HI−PS/LO−PS Terminals

High pressure switch (S4) is factory wired into the defrost
board HI−PS terminals. When (S4) trips, the defrost board
will cycle off the compressor and the strike counter in the
board will count one strike.

Low pressure switch (S87) is factory wired into the defrost
board LO−PS terminals. When (S87) trips, the defrost
board will cycle off the compressor and the strike counter
in the board will count one strike.
(S87) is ignored during certain conditions:

 During the defrost cycle and 90 seconds after the

termination of defrost

 When the average ambient sensor temperature is

below 15 F (−9)

 For 90 seconds following the start up of the

compressor

 During "Test" mode

3−Strike Lockout Feature
(Board 60L3901)

 The internal control logic of the board counts the pres-

sure switch trips only while the Y1 (Input) line is active. If
a pressure switch opens and closes twice 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 third time during the current
Y1 (Input), the control will enter a lockout condition.

 The 3−strike pressure switch lockout condition can be re-

set by cycling OFF the 24−volt power supply to the con­trol board or by shorting the TEST pins. All timer func­tions (run times) will also be reset.

 If a pressure switch becomes open while the Y1 Out line

is engaged, a 5 minute short cycle will occur after the
switch closes.

5−Strike Lockout Feature
(Boards 46M8201, 56M8501)

 The internal control logic of the board counts the pres-

sure switch trips only while the Y1 (Input) line is active. If
a pressure switch opens and closes 4 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.

 The 5−strike pressure switch lockout condition can be re-

set by cycling OFF the 24−volt power supply to the con­trol board or by shorting the TEST pins. All timer func­tions (run times) will also be reset.

 If a pressure switch becomes open while the Y1 Out line

is engaged, a 5 minute short cycle will occur after the
switch closes.

Operational Description

The demand defrost board has three basic operational
modes: Normal, Defrost, and Calibration.

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.

Defrost Mode

When a defrost cycle is initiated, the control energizes the
reversing valve solenoid and turns off the condenser fan.
The control will also put 24VAC on the W1" (auxiliary heat)
line. The unit will stay in this mode until either the coil sensor
temperature is above the selected termination tempera­ture, the defrost time of 14 minutes has been completed, or
the room thermostat demand cycle has been satisfied. (If
the temperature select shunt is not installed, the default ter­mination temperature will be 100°F.) If the room thermostat
demand cycle terminates the cycle, the defrost cycle will be
held until the next room thermostat demand cycle. If the coil
sensor temperature is still below the selected termination
temperature, the control will continue the defrost cycle until
the cycle is terminated in one of the methods mentioned
above. If a defrost is terminated by time and the coil temper­ature did not remain above 35°F (2°C) for 4 minutes, the
control will go to the 34−minute Time/Temperature mode.

DELAY" PINS

The 56M8501 defrost board has a field selectable function
to reduce occasional noise that may occur while the unit is
cycling in and out of defrost mode. When a jumper is
installed on the DELAY" pins, the compressor will cycle off
for 30 seconds going in and out of defrost mode. Units are
shipped with jumper installed on DELAY" pins.

NOTE − 30 second off cycle is not functional when
jumpering TEST" pins.

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 a temperature differential
required to allow a defrost cycle.

Page 7