Lennox T?CLASS TPA S4 Information Manual

Page 1

© 2006 Lennox Industries Inc.

Corp. 0632−L6

TPA*S4

Service Literature

3, 3.5, 4 and 5 ton

10.5, 12.3, 14 and 17.6 kW

Revised 05−2009

T−CLASStTPA*S4 COMMERCIAL SERIES UNITS

The TPA*S4 is a HFC−410A commercial split-system
heat pump. The series is designed for use with expansion
valves (TXV). All TPA*S4 units utilize scroll compressors.

TPA*S4 series units are available in 3, 3.5, 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.

WARNING

Improper installation, adjustment, alteration, service
or maintenance can cause personal injury, loss of
life, or damage to property.

Installation and service must be performed by a
licensed professional installer (or equivalent) or a
service agency.

IMPORTANT

This unit must be matched with an indoor coil as
specified in Lennox’ Engineering Handbook. Coils
previously charged with HCFC−22 must be flushed.

Table of Contents

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

Optional Accessories Page 3. . . . . . . . . . . . . . . . .

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

II Refrigerant System Page 8. . . . . . . . . . . . . . . . .

III Charging Page 10. . . . . . . . . . . . . . . . . . . . . . . . .

IV Maintenance Page 16. . . . . . . . . . . . . . . . . . . . . .

V Diagrams Page 17. . . . . . . . . . . . . . . . . . . . . . . . .

MODEL NUMBER IDENTIFICATION

TPA Y1036 S 44 n

Major Design Sequence

A = 1st Generation

B = 2nd Generation

Brand/Family

T = T−Classt Product Line

Unit Type

P = Heat Pump Outdoor Unit

Nominal Cooling Capacity − Tons

036 = 3 Tons

042 = 3.5 Tons

048 = 4 Tons
060 = 5 Tons

Cooling Efficiency

S = Standard Efficiency

Minor Design Sequence

1 = 1st Revision
2 = 2nd Revision
3 = 3rd Revision

Vol ta ge

Y = 208/230V-3 phase-60hz
G = 460V-3 phase-60hz

Refrigerant Type

4 = R−410A

Part Load Capability

N = No part load, single stage compressor

Coil type

4 = Four−sided

Page 2

Revised 05−2009TPA*S4

SPECIFICATIONS

General
Data

Model No. TPA036S4 TPA042S4 TPA048S4 TPA060S4

Nominal Tonnage 3 3.5 4 5

Connections
(sweat)

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

Vapor line o.d. − in. 7/8 7/8 7/8 1-1/8

1

Refrigerant HFC−410A charge furnished 8 lbs. 12 oz. 10 lbs. 10 oz. 13 lbs. 2 oz. 15 lbs. 3 oz.

Outdoor
Coil

Net face area

sq. ft.

Outer coil 15.21 18.66 21.11 29.09

Inner coil 14.50 17.95 20.31 28.16

Tube diameter 5/16 5/16 5/16 5/16

Number of rows 2 2 2 2

Fins per inch 22 22 22 22

Outdoor
Fan

Diameter − in. − No. of Blades 18 − 4 22 − 4 22 − 4 22 − 4

Motor hp 208/230V − 1/5

460V − 1/6

1/3 1/3 1/4

Cfm 2450 3890 3890 3830

Rpm 1100 1080 1085 830

Watts 190 400 375 330

Shipping Data − lbs. 1 package 180 220 250 255

ELECTRICAL DATA

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

2

Maximum overcurrent protection (amps) 20 15 30 15 30 15 35 15

3

Minimum circuit ampacity 14.2 7.8 18.6 8.3 18.8 8.6 21.3 10.7

Compressor Rated Load Amps

10.4 5.8 13.5 6.0 13.7 6.2 15.6 7.8

Locked Rotor Amps

88 38 88 44 83.1 41 110 52

Power Factor

.85 .84 .83 .81 .90 .92 .90 .91

Outdoor
Fan Motor

Full Load Amps

1.1 .55 1.7 1.0 1.7 1.0 1.7 1.0

Locked Rotor Amps

1.9 1.1 4.1 2.2 4.1 2.2 3.1 2.3

Page 3

Revised 05−2009TPA*S4

OPTIONAL ACCESSORIES − must be ordered extra

Model No. TPA036S4 TPA042S4 TPA048S4 TPA060S4

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

92M90 S S

12W21 S

92M94 S

4

Low Ambient Kit 54M89 S S S S

Low Ambient Control Option (down to 30°F) See table below See table below See table below See table below

Mild Weather Kit 33M07 S S S S

Monitor Kit − Service Light 76F53 S S S S

Mounting Base 69J06 S

69J07 S S S

Outdoor
Thermostat
Kit

Thermostat 56A87 S S S S

Mtg. Box 31461 S S S S

Refrigerant
Line Sets

L15−65−30, L15−65−40, or L15−65−50 S S S

Field Fabricate S

Time Delay Relay Kit 58M51 S S S 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

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

2

HACR type circuit breaker or fuse.

3

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

4

Freezestat is recommended with Low Ambient Kit.

LOW AMBIENT CONTROL Option (Down to 0°F)

Order one each: Speed Control Kit, Weatherproof Kit, Outdoor Fan Motor and Capacitor

Model No. TPA036S2

TPA048S2 TPA060S2
Speed Control Kit X5867 S S S

Weatherproof Kit 56N41 S S S
Outdoor

Fan Motor

1/2 HP − 230V 69H75 S S S

460V 69H76 S S S

Capacitor with mounting bracket 53H06 S S S

IMPORTANT

The Clean Air Act of 1990 bans the intentional
venting of refrigerant (CFCs, HFCs, and HCFCs) as of
July 1, 1992. Approved methods of recovery,
recycling or reclaiming must be followed. Fines
and/or incarceration may be levied for
noncompliance.

CAUTION

Physical contact with metal edges and corners while
applying excessive force or rapid motion can result
in personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.

Page 4

Revised 05−2009TPA*S4

I − UNIT COMPONENTS

Unit components are illustrated in figure 1.

TPA*S4 UNIT COMPONENTS

FIGURE 1

control box

service valves

compressor

reversing valve

condenser fan

drier

muffler

FIGURE 2

CAPACITOR

(C1)

COMPRESSOR

CONTACTOR

(K1)

TPA*S4 UNIT CONTROL BOX

GROUNDING

LUG

DEFROST

CONTROL

(CMC1)

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.

A − Control Box (Figure 2)

TPA*S4 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

1 − Compressor Contactor K1

The compressor is energized by a contactor located in the
control box. See figure 2. Three−pole contactors are used
in TPA*S4 series units. K1 is energized through the
control board by the indoor thermostat terminal Y1 (24V)
when thermostat demand is present.

2 − Capacitor C1

All units use single−phase PSC outdoor fan motors which
require a run c a p a c i t o r. Ra t i n g s for c a p a c i t o r will be on
fan motor nameplate. C1 aids in the start up of outdoor
fan B4.

3 − Defrost System

The TPA036S4 defrost system includes two components:
a defrost thermostat and a defrost control.

Defrost Thermostat

The defrost thermostat is located on the liquid line between
the check/expansion valve and the distributor. When
defrost thermostat senses 42°F (5.5°C) or cooler, the
thermostat 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).

Page 5

Revised 05−2009TPA*S4

Defrost Control

The defrost control board includes the combined functions
of a time/temperature defrost control, defrost relay,
diagnostic LEDs and terminal strip for field wiring
connections. See figure 4.

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.

TPA036S4 Outdoor Unit Defrost Control

Board

FIGURE 4

LEDs

24v terminal

strip

Timing

Pins

Test Pins

Compressor

Delay Pins

Reversing

Valve

Low Pressure
Switch (S87)

High Pressure
Switch (S4)

Defrost

Thermostat

Defrost Control Timing Pins

Each timing pin selection provides a different
accumulated compressor run time period for one defrost
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 4). 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 re−applied.

Compressor Delay

The defrost board has a field−selectable function to reduce
occasional sounds that may occur while the unit is cycling
in and out of the defrost mode. The compressor will be
cycled off for 30 seconds going in and out of the defrost
mode when the compressor delay jumper is removed.

NOTE − The 30-second off" cycle is not functional when
jumpering the TEST pins.

Time Delay

The timed-off delay is five minutes long. The delay helps to
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 Circuit

The defrost control incorporates two pressure switch
circuits. The optional high pressure switch (S4) connects to
the board’s HI PS terminals. The board also includes
connections for an optional low pressure, or
loss-of-charge-pressure, switch (S87). See figure 4 for
switch terminal location.

During a single demand cycle, the defrost control will lock
out the unit after the fifth time that the circuit is interrupted
by any pressure switch wired to the control board. In
addition, the diagnostic LEDs will indicate a locked-out
pressure switch after the fifth occurrence of an open
pressure switch (see Table 1). The unit will remain locked
out until power to the board is interrupted, then
re-established 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 as follows:

S during the TEST mode,

S during the defrost cycle,

S during the 90-second start-up period,

S 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.

Page 6

Revised 05−2009TPA*S4

Diagnostic LEDs

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

TABLE 1

Defrost Control Board Diagnostic LED

Mode Green LED (DS2)

Red LED
(DS1)

No power to control OFF OFF

Normal operation /
power to control

Simultaneous Slow FLASH

Anti-short cycle lock­out

Alternating Slow FLASH

Low pressure switch
fault (Optional)

OFF Slow FLASH

Low pressure switch
lockout (Optional)

OFF ON

High pressure switch
fault (Optional)

Slow FLASH OFF

High pressure switch
lockout (Optional)

ON OFF

B − Compressor

All TPA*S4 units utilize a scroll compressor. The scroll
compressor design is simple, efficient and requires few
moving parts. A cutaway diagram of the scroll compressor is
shown in figure 5. The scrolls are located in the top of the
compressor can and the motor is located just below. The oil
level is immediately below the motor.

The scroll is a simple compression concept centered around
the unique spiral shape of the scroll and its inherent properties.
Figure 6 shows the basic scroll form. Two identical scrolls are
mated together forming concentric spiral shapes (figure 7).
One scroll remains stationary, while the other is allowed to
"orbit" (figure 8). Note that the orbiting scroll does not rotate or
turn but merely orbits the stationary scroll.

FIGURE 5

SCROLL COMPRESSOR

DISCHARGE

SUCTION

NOTE − During operation, the head of a scroll compressor may
be hot since it is in constant contact with discharge gas.

FIGURE 6

SCROLL FORM

FIGURE 7

STATIONARY SCROLL

ORBITING SCROLL

DISCHARGE

SUCTION

CROSS−SECTION OF SCROLLS

TIPS SEALED BY
DISCHARGE PRESSURE

DISCHARGE
PRESSURE

The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (figure
8 − 1). The centrifugal action of the orbiting scroll seals off the
flanks of the scrolls (figure 8 − 2). As the orbiting motion
continues, the gas is forced toward the center of the scroll and
the gas pocket becomes compressed (figure 8 − 3). When the
compressed gas reaches the center, it is discharged vertically
into a chamber and discharge port in the top of the compressor
(figure 7). The discharge pressure forcing down on the top
scroll helps seal off the upper and lower edges (tips) of the
scrolls (figure 7). During a single orbit, several pockets of gas
are compressed simultaneously providing smooth continuous
compression.

The scroll compressor is tolerant to the effects of liquid return.
If liquid enters the scrolls, the orbiting scroll is allowed to
separate from the stationary scroll. The liquid is worked toward
the center of the scroll and is discharged. If the compressor is
replaced, conventional Lennox cleanup practices must be
used.

Due to its efficiency, the scroll compressor is capable of
drawing a much deeper vacuum than reciprocating
compressors. Deep vacuum operation can cause
internal fusite arcing resulting in damaged internal parts
and will result in compressor failure. Never use a scroll
compressor for evacuating or pumping−down" the
system. This type of damage can be detected and will
result in denial of warranty claims.

The scroll compressor is quieter than a reciprocating
compressor, however, the two compressors have much
different sound characteristics. The sounds made by a
scroll compressor do not affect system reliability,
performance, or indicate damage.

See compressor nameplate and ELECTRICAL DATA
table on page 2 for compressor specifications.

Page 7

Revised 05−2009TPA*S4

1

2

3

4

SUCTION

POCKET

SUCTION

ORBITING SCROLL

STATIONARY SCROLL

SUCTION

SUCTION

DISCHARGE

POCKET

SUCTION

INTERMEDIATE PRESSURE

GAS

CRESCENT

SHAPED

GAS POCKET

HIGH PRESSURE GAS

FLANKS SEALED

BY CENTRIFUGAL

FORCE

MOVEMENT OF ORBIT

FIGURE 8

Make sure all power is disconnected before
beginning electrical service procedures.

DANGER

C − Outdoor Fan Motor B4

All units use single−phase PSC fan motors . In a l l units, t h e
condenser fan is controlled by the compressor
contactor (and defrost control during defrost cycles).

ELECTRICAL DATA tables in this manual show
specifications for condenser fans used in TPA*S4s.

Access to the condenser fan motor on all units is gained
by removing the seven screws securing the fan
assembly. See figure 9. The outdoor fan motor is
removed from the fan guard by removing the four nuts
found on the top panel. If outdoor fan motor must be
replaced, align fan hub flush with motor shaft. Drip loops
should be used in wiring when servicing motor.

FAN

CONDENSER FAN MOTOR

AND COMPRESSOR ACCESS

Remove (7) screws

REMOVE (7) SCREWS

SECURING FAN GUARD.

REMOVE FAN GUARD/FAN

ASSEMBLY.

FAN GUARD

WIRING

FIGURE 9

Remove (4) nuts

ALIGN FAN HUB

FLUSH WITH

MOTOR SHAFT

D − Reversing Valve L1 and Solenoid

A refrigerant reversing valve with electro−mechanical
solenoid is used to reverse refrigerant flow during unit
operation. The reversing valve requires no maintenance.
The only replaceable part is the solenoid. If the reversing
valve itself has failed, it must be replaced.

If replacement is necessary, access reversing valve by
removing the outdoor fan motor. Refer to figure 9.

E − Crankcase Heater HR1 and Optional

Thermostat S40

Crankcase heater HR1 prevents liquid from accumulating
in the compressor. HR1 is controlled by crankcase heater
thermostat S40, located on the liquid line. When liquid line
temperature drops below 50° F, S40 closes energizing
HR1. S40 opens when liquid line temperature reaches 70°.

F − High Pressure Switch S4

S4 is a manual re−set switch located on the liquid line.
When liquid line pressure rises above the factory setting of
590 + 10 psi, the switch opens and shuts off the
compressor.

G − Low Pressure Switch S87

S87 is an auto−reset low pressure switch located on the
suction line. The switch shuts of the compressor when
suction pressure drops below the factory setting. The
switch is ignored during the first 90 seconds of compressor
start up, during defrost operation,90 seconds after defrost
operation and during test mode. The switch is factory set to
open at 25 +

5 psig and close at 40 + 5 psig. These settings

are not adjustable.

Page 8

Revised 05−2009TPA*S4

II − REFRIGERANT SYSTEM

FIGURE 10

TPA*S4 COOLING CYCLE (SHOWING MANIFOLD GAUGE CONNECTIONS)

OUTDOOR

COIL

DEFROST THERMOSTAT

EXPANSION/CHECK

VALV E

BI−FLOW

FILTER / DRIER

TO

LOW

PRESSURE

HIGH

PRESSURE

COMPRESSOR

REVERSING VALVE

VAPOR

LINE

VALV E

MUFFLER

NOTE − ARROWS INDICATE DIRECTION OF REFRIGERANT FLOW

SERVICE

PORT

SUCTION

EXPANSION/CHECK

VALV E

INDOOR UNIT

OUTDOOR UNIT

LIQUID LINE

SERVICE

PORT

GAUGE MANIFOLD

DISTRIBUTOR

INDOOR

COIL

TO

HFC−410A

DRUM

FIGURE 11

TPA*S4 HEATING CYCLE (SHOWING MANIFOLD GAUGE CONNECTIONS)

OUTDOOR

COIL

DEFROST THERMOSTAT

EXPANSION/CHECK

VALV E

BI−FLOW

FILTER / DRIER

LOW

PRESSURE

HIGH

PRESSURE

COMPRESSOR

REVERSING VALVE

VAPOR

LINE

VALV E

MUFFLER

NOTE − ARROWS INDICATE DIRECTION OF REFRIGERANT FLOW

SERVICE

PORT

SUCTION

EXPANSION/CHECK

VALV E

INDOOR UNIT

OUTDOOR UNIT

LIQUID LINE

SERVICE

PORT

GAUGE MANIFOLD

DISTRIBUTOR

INDOOR

COIL

TO

HFC−410A

DRUM

Page 9

Revised 05−2009TPA*S4

A − Plumbing

Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections). Use Lennox
L15 (sweat) series line sets as shown in table 2.

TABLE 2

Refrigerant Line Sets

Model

Field
Connections

Recommended Line Set

Liquid
Line

Vapor
Line

Liquid
Line

Vapor
Line

L15
Line Sets

−036

−048

3/8 in.
(10 mm)

7/8 in
(22 mm)

3/8 in.
(10
mm)

7/8 in
(22 mm)

L15−65
15 ft. − 50 ft.
(4.6 m − 15
m)

−060

3/8 in.
(10 mm)

1−1/8 in.
(29 mm)

3/8 in.
(10
mm)

1−1/8 in.
(29 mm)

Field
Fabricated

B − Service Valves

The liquid and vapor line service valves (figures 12 and 13)
and gauge ports are accessible from outside the unit.

Each valve is equipped with a service port. The service ports
are used for leak testing, evacuating, charging and checking
charge. A Schrader

®

valve is factory installed. A service port

cap is supplied to protect the Schrader

®

valve from

contamination and serve as the primary leak seal.

NOTE-Always keep valve stem caps clean.

To Access Schrader® Port:

1 − Remove service port cap with an adjustable wrench.

2 − Connect gauge to the service port.

3 − When testing is completed, replace service port cap.

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

To Open Liquid or Vapor Line Service Valve:

1 − Remove stem cap with an adjustable wrench.

2 − Using service wrench and hex head extension (5/16 for

vapor line and 3/16 for liquid line), back the stem out
counterclockwise until the valve stem just touches the
retaining ring.

3 − Replace stem cap and tighten finger tight, then tighten an

additional 1/6 turn.

Do not attempt to backseat this valve. Attempts to
backseat this valve will cause snap ring to explode
from valve body under pressure of refrigerant.
Personal injury and unit damage will result.

DANGER

To Close Liquid or Vapor Line Service Valve:

1 − Remove stem cap with an adjustable wrench.

2 − Using service wrench and hex head extension (5/16 for

vapor line and 3/16 for liquid line), turn stem clockwise to
seat the valve. Tighten firmly.

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

additional 1/6 turn.

FIGURE 12

LIQUID LINE SERVICE VALVE (VALVE OPEN)

SCHRADER

®

VALV E

SERVICE

PORT

SERVICE

PORT

CAP

INSERT HEX

WRENCH HERE

TO INDOOR COIL

TO COMPRESSOR

STEM CAP

SCHRADER® VALVE OPEN

TO LINE SET WHEN VALVE IS

CLOSED (FRONT SEATED)

SERVICE

PORT

SERVICE

PORT CAP

RETAINING RING

STEM CAP

TO

COMPRESSOR

INSERT HEX

WRENCH HERE

LIQUID LINE SERVICE VALVE (VALVE CLOSED)

VALVE FRONT

SEATED

TO INDOOR COIL

SUCTION LINE (BALL TYPE) SERVICE VALVE

(VALVE OPEN)

FIGURE 13

SCHRADER® CORE

SERVICE PORT

SERVICE

PORT

CAP

STEM CAP

FROM INDOOR COIL

TO COMPRESSOR

STEM

USE ADJUSTABLE WRENCH

ROTATE STEM CLOCKWISE 90_ TO CLOSE

ROTATE STEM COUNTER-CLOCKWISE 90_ TO OPEN

BALL

(SHOWN OPEN)

Page 10

Revised 05−2009TPA*S4

Vapor Line (Ball Type) Service Valve
5 ton unit only

A ball-type full service valve is used on TPA060S4N4xY
units only. Va l v e s are not re−buildable. If a valve has failed it
must be replaced. A ball valve is illustrated in figure 13.

The ball valve is equipped with a service port. A Schrader

®

valve is factory installed. A service port cap is supplied to
protect the Schrader

®

valve from contamination and

assure a leak free seal.

III − CHARGING

A − Pumping Down System

CAUTION

Deep vacuum operation (operating compressor
at 0 psig or lower) can cause internal fusite
arcing resulting in a damaged or failed
compressor. This type of damage will result in
denial of warranty claim.

The system may be pumped down when leak checking the
line set and indoor coil or making repairs to the line set or
indoor coil.

1− Attach gauge manifold.

2− Front seat (close) liquid line valve.

3− Start outdoor unit.

4− Monitor suction gauge. Stop unit when 0 psig is reached.

5− Front seat (close) suction line valve.

B − Leak Testing (To Be Done Before

Evacuating)

1− Attach gauge manifold and connect a drum of dry

nitrogen to center port of gauge manifold.

2− Open high pressure valve on gauge manifold and

pressurize line set and indoor coil to 150 psig (1034
kPa).

3− Check lines and connections for leaks.

NOTE  The preferred method is to use an electronic
leak or Halide detector. Add a small amount of HCFC−22
(3 to 5 psig [20kPa to 34kPa]) then pressurize with
nitrogen to 150 psig.

4− Release nitrogen pressure from the system, correct any

leaks and recheck.

DANGER

When using dry nitrogen, a pressure reducing regu­lator must be used to prevent excessive pressure in
gauge manifold, connecting hoses, and within the
system. Regulator setting must not exceed 150 psig
(1034 kpa). Failure to use a regulator can cause
equipment failure resulting in injury or death.

C − Evacuating the System

1− Attach gauge manifold. Connect vacuum pump (with

vacuum gauge) to center port of gauge manifold. With
both manifold service valves open, start pump and
evacuate indoor coil and refrigerant lines.

IMPORTANT

A temperature vacuum gauge, mercury vacuum (U−
tube), or thermocouple gauge should be used. The
usual Bourdon tube gauges are not accurate
enough in the vacuum range.

IMPORTANT

The compressor should never be used to evacu­ate a refrigeration or air conditioning system.

2− Evacuate the system to 29 inches (737mm) vacuum.

During the early stages of evacuation, it is desirable to
stop the vacuum pump at least once to determine if there
is a rapid loss of vacuum. A rapid loss of vacuum would
indicate a leak in the system and a repeat of the leak
testing section would be necessary.

3− After system has been evacuated to 29 inches

(737mm), close gauge manifold valves to center port,
stop vacuum pump and disconnect from gauge
manifold. Attach an upright nitrogen drum to center
port of gauge manifold and open drum valve slightly to
purge line at manifold. Break vacuum in system with
nitrogen pressure by opening manifold high
pressure valve. Close manifold high pressure valve
to center port.

4− Close nitrogen drum valve and disconnect from

gauge manifold center port. Release nitrogen
pressure from system.

5− Connect vacuum pump to gauge manifold center

port. Evacuate system through manifold service
valves until vacuum in system does not rise above
.5mm of mercury absolute pressure or 500 microns
within a 20−minute period after stopping vacuum pump.

6− After evacuation is complete, close manifold center port ,

and connect refrigerant drum. Pressurize system
slightly with refrigerant to break vacuum.

Page 11

Revised 05−2009TPA*S4

D − Charging  TPA*S4N41Y through

TPA*S4N42Y

The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is

determined by the 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 the
manifold gauge set to the service valves.

D low pressure gauge to vapor valve service port
D high pressure gauge to liquid valve service port

2.. Connect the center manifold hose to an upright
cylinder of HFC−410A.

3.. Set the room thermostat to call for heat. This will create
the necessary load for properly charging the system in
the cooling cycle.

4.. Use a digital thermometer to record the outdoor
ambient temperature.

5.. 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.

6.. The outdoor temperature will determine which
charging method to use. Proceed with the appropriate
charging procedure.

Charge using the Weigh−In Method − Outdoor
Temperature < 65_F (18_C)

If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, first, locate and repair any leaks and
then weigh in the refrigerant charge into the unit.

1.. Recover the refrigerant from the unit.

2.. Conduct leak check; evacuate as previously outlined.

3.. Weigh in the unit nameplate charge. If weighing
facilities are not available or if charging the unit during
warm weather, use one of the following procedures.

Charge using the Subcooling Method − Outdoor
Temperature < 65°F (18°C)

When the outdoor ambient temperature is below 65°F
(18°C), use the subcooling method to charge the unit. It
may be necessary to restrict the air flow through the
outdoor coil to achieve pressures in the 200−250 psig
(1379−1724 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 200−250 psig (1379−1724 kPa)
range. See figure 14.

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

*Four−sided unit shown.

FIGURE 14

1.. With the manifold gauge hose still on the liquid service
port and the unit’s pressure stabilized, use a digital
thermometer to record the liquid line temperature.

2.. At the same time, record the liquid line pressure reading.

3.. Use a temperature/pressure chart for HFC−410A to
determine the saturation temperature for the liquid line
pressure reading.

4.. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine
subcooling.

5.. Compare the subcooling value results with those in
table 3. If subcooling is greater than shown, recover
some refrigerant. If subcooling is less than shown, add
some refrigerant.

TABLE 3

TPA*S4N41Y through TPA*S4N42Y

TPA036S4 Subcooling Values for Charging

_ Saturation Temperature



_ Liquid Line Temperature

=

_ Subcooling Value

Model −036 −042 −048 −060

°F (°C)* 8 (4.4) 6 (3.3) 11 (6. 1 ) 11 (6. 1)

*F: +/−1.0°; C: +/−0.5°

Charge using the Approach Method − Outdoor
Temperature >

65_F (18_C)

The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results,
indoor temperature should be 70°F (21°C) to 80°F (26°C).
Monitor system pressures while charging.

1.. Record outdoor ambient temperature 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 4, Normal Operating Pressures." 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.

Page 12

Revised 05−2009TPA*S4

IMPORTANT

Use table 4 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.

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

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

TABLE 4

TPA*S4N41Y through TPA*S4N42Y

Normal Operating Pressures

1

MODEL

TPA036S4N41TPA042S4N41TPA048S4N41TPA060S4N4

1

5F(5C)2Liquid/Vapor Liquid/Vapor Liquid/Vapor Liquid/Vapor

Cooling Pressures

3

65 (18)

260 / 136 231 / 135 246 / 134 256 / 116

75 (24)

303 / 140 267 / 138 286 / 136 298 / 123

85 (29)

348 / 143 314 / 140 330 / 138 345 / 131

95 (35)

398 / 145 367 / 143 379 / 140 395 / 135

105 (41)

452 / 148 414 / 146 432 / 143 450 / 138

115 (45)

512 / 151 473 / 148 492 / 146 512 / 141

Heating Pressures

3

60 (15)

350 / 131 360 / 135 361 / 130 370 / 127

50 (10)

331 / 107 340 / 110 334 / 100 350 / 102

40 (4)

314 / 88 324 / 91 302 / 92 331 / 81

30 (−1)

290 / 74 307 / 73 300 / 73 309 / 62

20 (−7)

283 / 58 298 / 61 286 / 60 300 / 56

1 These are most−popular−match−up pressures. Indoor match up,

indoor air quality, and indoor load cause pressures to vary.
2 Temperature of the air entering the outdoor coil.
3 Liquid ±10 and Vapor ±5 psig.

TABLE 5

TPA*S4N41Y through TPA*S4N42Y

TPA036S4 Approach Values for Charging

_ Liquid Line Temperature



_ Outdoor Temperature

=

_ Approach Temperature

Model −036 −042 −048 −060

°F (°C)* 13 (7.2) 9 (5) 6 (3.3) 9 (5)

NOTE − For best results, use the same electronic thermometer to
check both outdoor-ambient and liquid-line temperatures.

*F: +/−1.0°; C: +/−0.5°

D − Charging  TPA*S4N43Y

This system is charged with HFC−410A refrigerant which
operates at much higher pressures than HCFC−22. The
recommended check expansion valve is approved for use
with HFC−410A. Do not replace it with a valve that is
designed to be used with HCFC−22. This unit is NOT
approved for use with coils that include metering orifices or
capillary tubes.

The unit is factory−charged with the amount of HFC−410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with a 15
foot (4.6 m) line set. For varying line set lengths and for

various indoor unit matchups, the refrigerant charge
must be adjusted per tables 6 (Page 14) and 8
(Page 15). A blank space is provided on the unit rating

plate to list the actual field charge.

IMPORTANT

Mineral oils are not compatible with HFC−410A. If oil
must be added, it must be a polyol ester oil.

Check Indoor Airflow before Charging

IMPORTANT

CHECK AIRFLOW BEFORE CHARGING!

NOTE − Be sure that filters and indoor and outdoor coils are
clean before testing.

Page 13

Revised 05−2009TPA*S4

Step 1. Determine the desired DTMeasure entering air tempera-
ture using dry bulb (A) and wet bulb (B). DT is the intersecting value
of A and B in the table (see triangle).

Step 2. Find temperature drop across coilMeasure the coil’s dry
bulb entering and leaving air temperatures (A and C). Temperature
Drop Formula: (T

Drop

) = A minus C.

Step 3. Determine if fan needs adjustmentIf the difference be-
tween the measured T

Drop

and the desired DT (T

Drop

–DT) is within

+

3º, no adjustment is needed. See examples: Assume DT = 15 and

A temp. = 72º, these C temperatures would necessitate stated ac­tions:

Cº T

Drop

– DT = ºF ACTION

53º 19 – 15 = 4 Increase the airflow
58º 14 – 15 = −1 (within +

3º range) no change

62º 10 – 15 = −5 Decrease the airflow

Step 4. Adjust the fan speedSee indoor unit instructions to in-

crease/decrease fan speed.

Changing air flow affects all temperatures; recheck temperatures to
confirm that the temperature drop and DT are within +

3º.

DT

80 24 24 24 23 23 22 22 22 20 19 18 17 16 15
78 23 23 23 22 22 21 21 20 19 18 17 16 15 14
76 22 22 22 21 21 20 19 19 18 17 16 15 14 13
74 21 21 21 20 19 19 18 17 16 16 15 14 13 12

72 20 20 19 18 17 17 16 15 15 14 13 12 11 10

70 19 19 18 18 17 17 16 15 15 14 13 12 11 10

57 58 59 60 61 62 63 64 65 66 67 68 69 70

Temp.
of air
entering
indoor
coil ºF

INDOOR
COIL

DRY BULBDRY

BULB

WET

BULB

B

T

Drop

19º

A

Dry−bulb

Wet−bulb ºF

A

72º

B

64º

C

53º

air flowair flow

All temperatures are
expressed in ºF

Figure 15. Checking Indoor Airflow over Evaporator Coil using Delta−T (DT) Chart

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

OUTDOOR

COIL

CHECK

EXPANSION VALVE

BI−FLOW
FILTER /
DRIER

TO

HFC−410A

DRUM

LOW

PRESSURE

COMPRESSOR

REVERSING VALVE

VAPOR
LINE
VALV E

MUFFLE

R

NOTE − ARROWS INDICATE DIRECTION
OF REFRIGERANT FLOW

CHECK EXPANSION VALVE

INDOOR UNIT

OUTDOOR

UNIT

LIQUID

SERVICE

PORT

GAUGE

MANIFOLD

DISTRIBUTOR

INDOOR

COIL

VAPOR
SERVICE
PORT

HUGH

PRESSURE

LIQUID
LINE
VALV E

Figure 16. TPA*S4N43Y Cooling Cycle (Showing Gauge Manifold Connections)

Page 14

Revised 05−2009TPA*S4

Cooling mode indoor airflow check

Check airflow using the Delta−T (DT) process (figure 15).

Heating mode indoor airflow check

Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:

S temperature rise between the return air and supply air

temperatures at the indoor coil blower unit,

S measuring voltage supplied to the unit,
S measuring amperage being drawn by the heat unit(s).

Then, apply the measurements taken in following formula
to determine CFM:

CFM =

Amps x Volts x 3.41

1.08 x Temperature rise (F)

Setup for Charging

Connect the manifold gauge set to the unit’s service ports
(see figure 16):

S low pressure gauge to vapor service port

S high pressure gauge to liquid service port

Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HFC−410A.

Calculating charge

If the system is void of refrigerant, first, locate and repair
any leaks and then weigh in the refrigerant charge into the
unit. To calculate the total refrigerant charge:

Amount
specified
on
nameplate

Adjust amt. for
variation in
line set length
(table 6)

Additional charge
specified per
indoor unit matchup
(table 8)

To ta l
charge

+ + =

Weigh−in Charging Method

Weigh−in:

1.. Recover the refrigerant from the unit.

2.. Conduct leak check; evacuate as previously outlined.

3.. Weigh in the unit nameplate charge plus any charge
required for line set differences from 15 feet and any
extra indoor unit matchup amount per table 8. (If
weighing facilities are not available, use the subcooling
method.)

Table 6. Charge per Line Set Lengths

Liquid Line
Set Diameter

Oz. per 5 ft. (g per 1.5m) adjust from
15 ft. (4.6m) line set*

3/8 in. (9.5mm) 3 ounce per 5 ft. (85g per 1.5m)

NOTE − *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.

Subcooling Charging Method

Requirementsthese items are required for charging:

S Manifold gauge set connected to unit.
S Thermometers for measuring outdoor ambient, liquid

line, and vapor line temperatures.

When to use cooling modeWhen outdoor temperature
is 60°F (15°C) and above, use cooling mode to adjust
charge.

When to use heating modeWhen the outdoor
temperature is below 60°F (15°C), use the heating mode to
adjust the charge.

Adding Charge for Indoor MatchupsTable 8 lists all
the Lennox recommended indoor unit matchups along with
the charge levels for the various sizes of outdoor units.

Table 7. Normal Operating Pressures − Liquid +10 and Vapor +5 PSIG*

IMPORTANT

Use table 4 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.

TPA*S4N43Y

Mode

5F (5C)**

TPA036S4 TPA036S4 TPA036S4 TPA036S4

Liquid / Vapor Liquid / Vapor Liquid / Vapor Liquid / Vapor

Cooling

65 (18) 260 / 136 231 / 135 246 / 134 256 / 116
75 (24) 303 / 140 267 / 138 286 / 136 298 / 123
85 (29) 348 / 143 314 / 140 330 / 138 345 / 131
95 (35) 398 / 145 367 / 143 379 / 140 395 / 135
105 (41) 452 / 148 414 / 146 432 / 143 450 / 138
115 (45) 512 / 151 473 / 148 492 / 146 512 / 141

Heating

60 (15) 350 / 131 366 / 129 348 / 119 379 / 127
50(10) 331 / 111 348 / 110 334 / 105 361 / 109
40 (4) 314 / 91 333 / 91 312 / 84 341 / 89
30 (−1) 303 / 74 317 / 70 300 / 73 323 / 71
20 (−7) 290 / 62 298 / 58 286 / 60 310 / 60

*These are most−popular−match−up pressures. Indoor match up, indoor air quality, and indoor load cause pressures to vary.

**Temperature of the air entering the outside coil.

Page 15

Revised 05−2009TPA*S4

Table 8. Adding Charge per Indoor Unit Matchup using Subcooling Method

Use
cooling
mode

Use
heating
mode

1. Check the airflow (figure 15, Page 13) to be sure the indoor airflow is as required. (Make any air
flow adjustments before continuing with the following procedure.)

2. Measure outdoor ambient temperature; determine whether to use cooling mode or heating mode
to check charge.

3. Connect gauge set.

4. Check Liquid and Vapor line pressures. Compare pressures with Normal Operating Pressures table
4, (Table 4 is a general guide. Expect minor pressures variations. Significant differences may mean
improper charge or other system problem.)

5. Set thermostat for heat/cool demand, depending on mode being used:
Using cooling modeWhen the outdoor ambient temperature is 60°F (15°C) and above. Target

subcooling values in table below are based on 70 to 80°F (21−27°C) indoor return air temperature; if
necessary, operate heating to reach that temperature range; then set thermostat to cooling mode
setpoint to 68ºF (20ºC). When pressures have stabilized, continue with step 6..

Using heating modeWhen the outdoor ambient temperature is below 60°F (15°C). Target
subcooling values in table below are based on 65−75°F (18−24°C) indoor return air temperature; if
necessary, operate cooling to reach that temperature range; then set thermostat to heating mode
setpoint to 77ºF (25ºC). When pressures have stabilized, continue with step 6..

6. Read the liquid line temperature; record in the LIQº space.

7. Read the liquid line pressure; then find its corresponding temperature in the temperature/ pressure
table 13 and record it in the SATº space.

8. Subtract LIQº temp. from SATº temp. to determine subcooling; record it in SCº space.

9. Compare SCº results with table below, being sure to note any additional charge for line set and/or
matchup.

10. If subcooling value is greater than shown in table, remove refrigerant; if less than shown, add
refrigerant.

11. If refrigerant is added or removed, repeat steps 5. through 10. to verify charge.

60ºF (15ºC)

SATº
LIQº –
SCº =

D − Indoor Unit Matchups  TPA*S4N43Y

Table 9. TPA036S4N43Y

INDOOR MATCHUPS

Target

Subcooling

*Add

charge

g

Heat Cool

(+

5ºF)(+1ºF)

lb oz

CBX26UH−036 17 10 2 7

CBX27UH−036−230 10 5 2 7

CBX27UH−042−230 10 10 2 13

CBX32M−036, −042 10 5 2 7

CBX32MV−036−230 10 5 2 7

CBX40UHV−036 10 5 2 7

CH33−31A, −31B 10 5 2 8

CH33−36B 10 5 0 0

CH33−36C 10 5 0 5

CH33−42 10 5 2 8

CH33−44/48B 10 5 2 10

CH33−48C 10 5 2 10

CR33−30/36 25 5 0 6

CR33−48 25 5 2 8

CR33−50/60 10 5 2 10

CX34−36B 10 5 0 1

CX34−38 SN# 6007 and after 5 5 2 7

CX34−38 before SN# 6007 10 5 2 7

CX34−42B 10 5 0 1

CX34−44/48B 10 5 2 7

Table 10. TPA042S4N43Y

INDOOR MATCHUPS

Target

Subcooling

*Add

charge

g

Heat Cool

(+

5ºF)(+1ºF)

lb oz

CBX26UH−042 26 5 1 1

CBX26UH−048 10 12 4 5

CBX27UH−042−230 10 6 4 5

CBX27UH−048−230 10 6 4 5

CBX32M−036, −042 15 5 0 0

CBX32MV−036 15 5 0 0

CBX32MV−048−230 10 6 4 5

CBX40UHV−036 15 5 0 0

CBX40UHV−042, −048 10 6 4 5

CH33−43C, −48C 10 6 1 1

CH33−49C, −50/60C 10 6 4 5

CH33−60D 10 6 2 6

CR33−48 32 5 0 5

CR33−50/60 32 9 2 6

CR33−60 32 9 2 6

CX34−43C 10 6 1 1

CX34−49 10 6 3 7

CX34−50/60C 10 6 1 1

Page 16

Revised 05−2009TPA*S4

Table 11. TPA048S4N43Y

INDOOR MATCHUPS

Target

Subcooling

*Add

charge

g

Heat Cool

(+

5ºF)(+1ºF)

lb oz

CBX26UH−048 9 11 1 7

CBX26UH−060 24 18 2 7

CBX27UH−048−230 11 11 1 3

CBX27UH−060−230 24 18 2 7

CBX32M−048 11 11 1 3

CBX32M−060 11 11 1 3

CBX32MV−048 11 11 1 3

CBX32MV−060−230 11 11 1 3

CBX40UHV−048 11 11 1 3

CBX40UHV−060 11 11 1 3

CH33−43C 18 7 0 0

CH33−49C, −50/60C 11 11 1 3

CH33−60D 11 11 0 9

CH33−62D 11 11 1 10

CR33−50/60 25 7 0 9

CR33−60 25 7 0 9

CX34−49 11 11 1 1

CX34−60D 11 11 0 9

Table 12. TPA060S4N43Y

INDOOR MATCHUPS

Target

Subcooling

*Add

charge

g

Heat Cool

(+

5ºF)(+1ºF)

lb oz

CBX26UH−060 10 11 1 7

CBX27UH−060−230 10 9 0 13

CBX32MV−060 10 9 0 0

CBX32MV−068 10 9 0 9

CBX40UHV−060 10 9 0 0

CH33−60D 10 9 0 0

CH33−62D 10 9 0 11

CX34−62D 10 9 0 6

*Amount of charge required in additional to charge shown on unit

nameplate. (Remember to consider line set length difference.)

Table 13. HFC−410A Temp. (°F) − Pressure (Psig)

°F Psig °F Psig °F Psig °F Psig

−40 10.1 21 80.5 56 158.2 91 278.2

−35 13.5 22 82.3 57 161 92 282.3

−30 17.2 23 84.1 58 163.9 93 286.5

−25 21.4 24 85.9 59 166.7

94 290.8

−20 25.9 25 87.8 60 169.6 95 295.1

−18 27.8 26 89.7 61 172.6 96 299.4

−16 29.7 27 91.6 62 175.4 97 303.8

−14 31.8 28 93.5

63 178.5

98 308.2

−12 33.9 29 95.5 64 181.6 99 312.7

−10 36.1 30 97.5 65 184.3 100 317.2

−8 38.4 31 99.5 66 187.7 101 321.8

−6 40.7

32 100.8

67 190.9 102 326.4

−4 43.1 33 102.9 68 194.1 103 331

−2 45.6 34 105 69 197.3 104 335.7
0 48.2 35 107.1 70 200.6 105 340.5
1 49.5

36 109.2 71 203.9 106 345.3
2 50.9 37 111.4 72 207.2 107 350.1
3 52.2 38 113.6 73 210.6 108 355
4 53.6 39 115.8 74 214 109 360
5 55 40 118 75 217.4 110 365
6 56.4 41 120.3 76 220.9 111 370
7 57.9 42 122.6 77 224.4 112 375.1
8 59.3 43 125 78 228 113 380.2
9 60.8 44 127.3 79 231.6 114 385.4

10 62.3 45 129.7 80 235.3 11 5 390.7

11 63.9 46 132.2 81 239 116 396
12 65.4 47 134.6 82 242.7 11 7 401.3
13 67 48 137.1 83 246.5 118 406.7
14 68.6 49 139.6 84 250.3 11 9 412.2
15 70.2 50 142.2 85 254.1 120 417.7
16 71.9 51 144.8 86 258 121 423.2
17 73.5 52 147.4 87 262 122 428.8
18 75.2 53 150.1 88 266 123 434.5
19 77 54 152.8 89 270 124 440.2
20 78.7 55 155.5 90 274.1

125 445.9

IV − MAINTENANCE

At the beginning of each heating or cooling season, the
system should be cleaned as follows:

A − Outdoor Unit

1 − Clean and inspect condenser coil. (Coil may be

flushed with a water hose).

NOTE − Make sure all power is disconnected before
flushing coil with water.

2 − Visually inspect all connecting lines, joints and

coils for evidence of oil leaks.

NOTE-Outdoor fan motors are permanently

lubricated.

B − Indoor Coil

1 − Clean coil if necessary.

2 − Check connecting lines and coil for evidence of oil

leaks.

3 − Check condensate line and clean if necessary.

C − Indoor Unit

1 − Clean or change filters.
2 − Bearings are pre-lubricated and need no further

oiling.
3 − Check all wiring for loose connections.
4 − Check for correct voltage at unit.
5 − Check amp−draw on blower motor.

Page 17

Revised 05−2009TPA*S4

V − WIRING DIAGRAM AND SEQUENCE OF OPERATION

TPA*S4 230 VOLT UNIT DIAGRAM

5

1

2

4

3

6

COOLING:

Internal thermostat wiring energizes terminal O by cooling
mode selection, energizing the reversing valve L1.

1− Demand initiates at Y1 in the thermostat.

2− Assuming high pressure switch S4 and low pressure

switch S87 are closed, 24VAC energizes compressor
contactor K1.

3− K1-1 N.O. closes, energizing compressor (B1) and

outdoor fan motor (B4).

END OF COOLING DEMAND:

4− Demand is satisfied. Terminal Y1 is de-energized.

5− Compressor contactor K1 is de-energized.

6− K1-1 opens and compressor (B1) and outdoor fan motor

(B4) are de-energized and stop immediately.

FIRST STAGE HEAT:

Internal thermostat wiring de−energizes terminal O by heat­ing mode selection, de−energizing the reversing valve L1.

See steps 1, 2 and 3.

End of FIRST STAGE HEAT:

See steps 4, 5 and 6.

DEFROST MODE:

During heating operation when outdoor coil temperature drops below

35°F (2°C) or 42°F (5.5°C)defrost switch (thermostat) S6 closes.

Defrost control CMC1 begins timing. If defrost thermostat (S6) remains
closed at the end of the 30,60 or 90 minute period, defrost relay ener­gizes and defrost begins.

During defrost CMC1 energizes the reversing valve and W1 on the ter-

minal strip (operating indoor unit on the first stage heat mode), while
de-energizing outdoor fan motor B4.

Defrost continues 14 + 1 minutes or until thermostat switch (S6) opens.
When defrost thermostat opens, defrost control timer loses power and
resets.

When CMC1 resets, the reversing valve and W1 on the terminal strip
are de-energized, while the outdoor fan motor B4 is energized.

When CMC1 resets, the reversing valve and W1 on the terminal strip
are de-energized, while the outdoor fan motor B4 is energized.

Page 18

Revised 05−2009TPA*S4

TPA*S4 460 VOLT UNIT DIAGRAM

5

1

2

4

3

6

COOLING:

Internal thermostat wiring energizes terminal O by cooling
mode selection, energizing the reversing valve L1.

1− Demand initiates at Y1 in the thermostat.

2− Assuming high pressure switch S4 and low pressure

switch S87 are closed, 24VAC energizes compressor
contactor K1.

3− K1-1 N.O. closes, energizing compressor (B1) and

outdoor fan motor (B4).

END OF COOLING DEMAND:

4− Demand is satisfied. Terminal Y1 is de-energized.

5− Compressor contactor K1 is de-energized.

6− K1-1 opens and compressor (B1) and outdoor fan motor

(B4) are de-energized and stop immediately.

FIRST STAGE HEAT:

Internal thermostat wiring de−energizes terminal O by heat­ing mode selection, de−energizing the reversing valve L1.

See steps 1, 2 and 3.

End of FIRST STAGE HEAT:

See steps 4, 5 and 6.

DEFROST MODE:

During heating operation when outdoor coil temperature drops below

35°F (2°C) or 42°F (5.5°C)defrost switch (thermostat) S6 closes.

Defrost control CMC1 begins timing. If defrost thermostat (S6) remains
closed at the end of the 30,60 or 90 minute period, defrost relay ener­gizes and defrost begins.

During defrost CMC1 energizes the reversing valve and W1 on the ter-

minal strip (operating indoor unit on the first stage heat mode), while de­energizing outdoor fan motor B4.

Defrost continues 14 +

1 minutes or until thermostat switch (S6) opens.
When defrost thermostat opens, defrost control timer loses power and
resets.

When CMC1 resets, the reversing valve and W1 on the terminal strip
are de-energized, while the outdoor fan motor B4 is energized.

When CMC1 resets, the reversing valve and W1 on the terminal strip
are de-energized, while the outdoor fan motor B4 is energized.