Lennox 14HPX, 14HPX−018, 14HPX−024, 14HPX−030, 14HPX−036 Unit Information

Page 1

© 2007 Lennox Industries Inc.

Corp. 0719−L5

14HPX

Service Literature

1.5 to 5 ton

Revised 06−2008

14HPX SERIES UNITS

The 14HPX is a residential split-system heat pump. The
series is designed for use with expansion valves (TXV) and
HFC−410A refrigerant. All 14HPX units utilize scroll compres­sors.

14HPX series units are available in 1−1/2, 2, 2 -1/2, 3, 3

-1/2, 4 and 5 ton capacities. 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.

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.

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.

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.

CAUTION

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

Table of Contents

Specifications / Electrical Data Page 2. . . . . . . . .

I Unit Components Page 4. . . . . . . . . . . . . . . . . . .

II Refrigerant System Page 14. . . . . . . . . . . . . . . . .

III Charging Page 17. . . . . . . . . . . . . . . . . . . . . . . . .

IV Maintenance Page 22. . . . . . . . . . . . . . . . . . . . . .

V Diagrams Page 23. . . . . . . . . . . . . . . . . . . . . . . . .

Page 2

SPECIFICATIONS
General

Model No. 14HPX−018 14HPX−024 14HPX−030

6

14HPX−036

Data

Nominal Tonnage 1.5

2 2.5 3

1

Sound Rating Number 76 76 76 79

Connections

Liquid line o.d. − in. 3/8 3/8 3/8 3/8

(sweat)

Vapor line o.d. − in. 3/4

3/4 3/4 7/8

2

Refrigerant HFC−410A charge furnished 8 lbs. 4 oz. 8 lbs. 0 oz. 7 lbs. 2 oz. 9 lbs. 12 oz.

Outdoor

Net face area

Outer coil 13.30 13.30 15.21 19.39

Coil sq. ft.

Inner coil 12.60

12.60 14.50 18.77

Tube diameter − in. 5/16 5/16 5/16 5/16

No. of rows 2 2 2 2

Fins per inch 22 22 22 22

Outdoor

Diameter − in. 18 18 18 26

Fan

No. of Blades 3

3 3 4

Motor hp 1/10 1/10 1/10 1/3

Cfm 2165 2165 2232 4090

Rpm 1015 1015 1035 844

Watts 171 171 165 299

Shipping Data − lbs. 1 package 156 156 166 212
ELECTRICAL DATA

Line voltage data − 60 hz − 1ph 208/230V

208/230V 208/230V 208/230V

3

Maximum overcurrent protection (amps) 20 30 30 30

4

Minimum circuit ampacity 11.9 17.5 17.0 19.4

Compressor Rated Load Amps 8.97 13.46 13.1 14.1

p

Locked Rotor Amps 48 58 64 77

Power Factor 0.96 0.97 0.98 0.98

Outdoor

Full Load Amps 0.70 0.70 0.70 1.8

Fan Motor

Locked Rotor Amps 1.4

1.4 1.4 2.9

OPTIONAL ACCESSORIES − must be ordered extra
Compressor Crankcase Heater 93M04 S

S S

p

Factory S
Compressor Hard Start Kit 10J42 S S S S
Compressor Low Ambient Cut−Off 45F08 S S S S
Compressor Sound Cover 69J03 S S S S
Freezestat 3/8 in. tubing 93G35 S S S S

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

Hail Guards 92M89 S S

92M88 S

27W34 S

Indoor Blower Off Delay Relay 58M81 S S S S
Loss of Charge Kit 84M23 S S S S

5

Low Ambient Kit 54M89 S S S S
Mild Weather Kit 33M07 S S S S
Monitor Kit − Service Light 76F53 S S S S
Mounting Base 69J06 S S S

g

69J07 S

Outdoor

Thermostat 56A87 S S S S

Thermostat Kit

Mounting Box 31461 S

S S S

Refrigerant
Line Sets

L15−41−20
L15−41−30

L15−41−40
L15−41−50

S S S

e Sets

L15−65−30 L15−65−40

L15−65−50

S

Unit Stand−Off Kit 94J45 S S S S

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

1

Sound Rating Number rated in accordance with test conditions included in ARI Standard 270.

2

Refrigerant charge sufficient for 15 ft. length of refrigerant lines.

3

HACR type circuit breaker or fuse.

4

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

5

Crankcase Heater and Freezestat are recommended with Low Ambient Kit.

6

14HPX−036 not available in Canada.

Page 3

SPECIFICATIONS
General

Model No. 14HPX−042 14HPX−048 14HPX−060

Data

Nominal Tonnage 3.5

4 5

1

Sound Rating Number 79 80 80

Connections

Liquid line o.d. − in. 3/8 3/8 3/8

(sweat)

Vapor line o.d. − in. 7/8

7/8 1-1/8

2

Refrigerant HFC−410A charge furnished 12 lbs. 7 oz. 12 lbs. 10 oz. 16 lbs. 0 oz.

Outdoor

Net face area

Outer coil 24.93 24.93 29.09

Coil sq. ft.

Inner coil 24.13

24.13 28.16

Tube diameter − in. 5/16 5/16 5/16

No. of rows 2 2 2

Fins per inch 22 22 22

Outdoor

Diameter − in. 26 26 26

Fan

No. of Blades 4

4 4

Motor hp 1/3 1/3 1/3

Cfm 4347 4347 4550

Rpm 843 843 830

Watts 299 299 307

Shipping Data − lbs. 1 package 257 262 307

ELECTRICAL DATA

Line voltage data − 60 hz − 1ph 208/230V

208/230V 208/230V

3

Maximum overcurrent protection (amps) 40 50 60

4

Minimum circuit ampacity 24.2 29 34.8

Compressor

Rated Load Amps

17.94 21.79 26.41

p

Locked Rotor Amps

112

117 134

Power Factor

0.94 0.95 0.98

Outdoor

Full Load Amps

1.8 1.8 1.8

Fan Motor

Locked Rotor Amps

2.9

2.9 2.9

OPTIONAL ACCESSORIES − must be ordered extra
Compressor Crankcase Heater Factory S

S S

Compressor Hard Start Kit

10J42 S S

p

81J69 S
Compressor Low Ambient Cut−Off 45F08 S S S
Compressor Sound Cover 69J03 S S S
Freezestat

3/8 in. tubing 93G35 S S S
5/8 in. tubing 50A93 S S S

Hail Guards

27W36 S S

94M94 S
Indoor Blower Off Delay Relay 58M81 S S S

Loss of Charge Kit 84M23 S S S

5

Low Ambient Kit 54M89 S S S
Mild Weather Kit 33M07 S S S
Monitor Kit − Service Light 76F53 S S S
Mounting Base 69J07 S S S
Outdoor

Thermostat 56A87 S S S

Thermostat Kit

Mounting Box 31461 S

S S

Refrigerant
Line Sets

L15−65−30 L15−65−40

L15−65−50

S S

e Sets

Field Fabricate S

Unit Stand−Off Kit 94J45 S S S

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

1

Sound Rating Number rated in accordance with test conditions included in ARI Standard 270.

2

Refrigerant charge sufficient for 15 ft. length of refrigerant lines.

3

HACR type circuit breaker or fuse.

4

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

5

Crankcase Heater and Freezestat are recommended with Low Ambient Kit.

Page 4

I − UNIT COMPONENTS

Unit components are illustrated in figure 1.

14HPX UNIT COMPONENTS

FIGURE 1

service valves

compressor

reversing valve

condenser fan

drier

muffler

high pressure switch
(on liquid line, hidden)

txv valve

FIGURE 2

DUAL CAPACITOR

(C12)

COMPRESSOR

CONTACTOR

(K1)

14HPX UNIT CONTROL BOX

GROUNDING

LUG

DEFROST

CONTROL

(CMC1)

A − Control Box (Figure 2)

14HPX units are not equipped with a 24V transformer. All
24 VAC controls are powered by the indoor unit. Refer to
wiring diagram.

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 3.

24V THERMOSTAT TERMINAL STRIP

FIGURE 3

W1 C L R O Y1*Y2

*not used

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 14HPX series units. See wiring diagrams for specific
unit. K1 is energized through the CMC1 board by the in­door thermostat terminal Y1 (24V) when thermostat de­mand is present.

DANGER

Electric Shock Hazard.
May cause injury or death.

Disconnect all remote electrical power
supplies before opening unit panel. Unit
may have multiple power supplies.

Some units are equipped with single−
pole contactors. When unit is equipped
with a single−pole contactor, line voltage
is present at all components (even when
unit is not in operation).

2 − Dual Capacitor (C12)

The compressor and fan in 14HPX 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.

Page 5

3 − Defrost System (CMC1)

The demand defrost control 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 4.

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.

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 2.

24V TERMINAL
STRIP
CONNECTIONS

DIAGNOSTIC
LEDS

PRESSURE

SWITCH CIRCUIT

CONNECTIONS

TEST PINS

NOTE − Component Locations Vary by Board Manufacturer.

Y2 not used on 14HPX

SENSOR

PLUG IN

(COIL & AM-

BIENT

SENSORS)

REVERSING

VALV E

DELAY

PINS

LOW
AMBIENT
THERMOSTAT
PINS

DEFROST
TERMINATION
PIN SETTINGS

FIGURE 4

Defrost Control Pressure Switch Connections

The unit’s automatic reset pressure switches (LO PS − S87
and HI PS − S4) are factory−wired into the defrost board on
the LO−PS and HI−PS terminals, respectively.

(OPTIONAL) 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:

S during the defrost cycle and 90 seconds after the ter-

mination of defrost

S when the average ambient sensor temperature is be-

low 15° F (−9°C)

S for 90 seconds following the start up of the compressor
S during "test" mode

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

Defrost Control Pressure Switch Settings

High Pressure (auto reset) − trip at 590 psig; reset at 418.

Low Pressure (auto reset) − trip at 25 psig; reset at 40 psig.

5−Strike Lockout Feature

The internal control logic of the control 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.

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 and 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 control through a field-re­placeable harness assembly that plugs into the board.
Through the sensors, the control detects outdoor ambient
and coil temperature fault conditions. As the detected tem­perature changes, the resistance across the sensor
changes. Figure 5 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 in table 1.

TABLE 1

Sensor

Temperature
Range °F (°C)

Resistance values
range (ohms)

Pins/Wire
Color

Outdoor
(Ambient)

−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 increases
(see figure5).

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 1, 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
needs to be replaced.

Coil SensorThe coil temperature sensor (shown in fig­ure 6) 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.

Page 6

Ambient and Coil Sensor

RESISTANCE (OHMS)

TEMPERATURE (ºF)

5750

7450

9275

11775

15425

19975

26200

34375

46275

62700

100

90

80

70

60

50

40

30

20

10

0

10000 30000 50000 70000 90000

85300

FIGURE 5

COIL SENSOR

−
Clip coil temperature sensor from the de­frost board on the bend shown − 6th bend
up. Apply grease between bend and sen­sor.

AMBIENT
SENSOR

FIGURE 6

Ambient SensorThe ambient sensor (shown in figure 6)

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 control will not perform demand
defrost operation. The control 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.

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.

Defrost Temperature Termination Shunt (Jumper)
PinsThe defrost control 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 control 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.

Page 7

NOTE − The 30 second off cycle is NOT functional when
jumpering the TEST pins.

Operational Description

The defrost control has three basic operational modes:
normal, calibration, and defrost.

Normal ModeThe demand defrost control 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 control is considered uncali­brated when power is applied to the control, after cool
mode operation, or if the coil temperature exceeds the ter­mination temperature when it is in heat mode.

Calibration of the control 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. See figure 8 for calibration
mode sequence.

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

Detailed Defrost System Operation

Defrost CyclesThe demand defrost control initiates a

defrost cycle based on either frost detection or time.

S 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.

IMPORTANT − The demand defrost control will allow a
greater accumulation of frost and will initiate fewer de­frost cycles than a time/temperature defrost system.

S TimeIf 6 hours of heating mode compressor run time

has elapsed since the last defrost cycle while the coil
temperature remains below 35°F (2°C), the demand
defrost control will initiate a defrost cycle.

ActuationWhen the reversing valve is de−energized, the
Y1 circuit is energized, and the coil temperature is below
35°F (2°C), the board logs the compressor run time. If the
board is not calibrated, a defrost cycle will be initiated after
34 minutes of heating mode compressor run time. The con­trol will attempt to self−calibrate after this (and all other) de­frost cycle(s).

Calibration success depends on stable system tempera­tures during the 20−minute calibration period. If the control
fails to calibrate, another defrost cycle will be initiated after
45 minutes (90 minutes −1 to −4 boards) of heating mode
compressor run time. Once the defrost board is calibrated,
it initiates a demand defrost cycle when the difference be­tween the clear coil and frosted coil temperatures exceeds
the maximum difference allowed by the control OR after 6
hours of heating mode compressor run time has been
logged since the last defrost cycle.

NOTE − If ambient or coil fault is detected, the control will
not execute the TEST" mode.

TerminationThe defrost cycle ends when the coil tem­perature exceeds the termination temperature or after 14
minutes of defrost operation. If the defrost is terminated by
the 14−minute timer, another defrost cycle will be initiated
after 34 minutes of run time.

Test ModeWhen Y1 is energized and 24V power is be­ing applied to the control, 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 control 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).
Control timings are reduced, the low−pressure switch is ig­nored and the control 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 7)
for TEST" operation.

Note: The Y1 input must be active (ON) and the O" room
thermostat terminal into board must be inactive.

Defrost Control Diagnostics

See table 2 to determine defrost control operational condi­tions and to diagnose cause and solution to problems.

Page 8

If in COOLING Mode If in HEATING Mode If in DEFROST Mode

Short test pins for longer

than 1 second but less than

2 seconds

Short test pins for more than 2 seconds

Y1 Active (0" line inactive)

Test pin short REMAINS in place for more than 5 seconds Test pins short REMOVED before a

maximum of 5 seconds

Clear any short cycle lockout

and 5 strike fault lockout

function, if applicable. No

other functions will be

executed and unit will

continue in the mode it was

operating.

No further test mode

operation will be

executed until the test

short is removed and

reapplied.

The control will check for ambient

and coil faults (open or shorted).

If a fault exists

, the unit will

remain in Heat Mode and no

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 35ºF, the

unit will go into 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.

Clear any short cycle lockout and 5 strike

fault lockout function, if applicable.

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.

The unit will remain in Defrost mode

until termination on time or temperature

FIGURE 7