Lennox T?CLASS TPA024S4, T?CLASS TPA036S4, T?CLASS TPA048S4, T?CLASS TPA060S4 Unit Information
Service Literature
Corp. 0923−L10
01−2010
T−CLASSt
TPA*S4
M and T Voltages
TPA*S4 M and T Voltage
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
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs AND HFCs) as of July 1,
1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarceration
may be levied for noncompliance.
Units
TABLE OF CONTENTS
Specifications and Electrical Data 2. . . . . . . . . . . . . . . . . .
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Control Panel Parts Arrangement 4. . . . . . . . . . .
Typical Unit Parts Arrangement 5. . . . . . . . . . . . . . . . . . .
Model Number Identification 5. . . . . . . . . . . . . . . . . . . . . .
Unit Components 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Gauge Set and Service Valves 8. . . . . . . . . . .
Recovering Refrigerant from Existing System 10. . . . . .
Unit Placement 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
New or Replacement Line Set 12. . . . . . . . . . . . . . . . . . . .
Metering Devices and Flushing the System 15. . . . . . . .
Testing for Leaks 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evacuating the System 17. . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Connections 18. . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing Unit Void of Charge 20. . . . . . . . . . . . . . . . . . . .
Unit Start−Up 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Refrigerant 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Operation 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defrost System 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start−Up and Performance Checklist 28. . . . . . . . . . . . . .
Wiring Diagrams and Sequence of Operations 29. . . . .
The TPA*S4 is a commercial split-system heat pump. 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.
WARNING
Electric Shock Hazard. Can cause injury
or death. Unit must be grounded in
accordance with national and local
codes.
Line voltage is present at all components
when unit is not in operation on units with
single-pole contactors. Disconnect all
remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.
IMPORTANT
This model is designed for use in expansion valve
systems only. An indoor check expansion valve
approved for use with HFC−410A refrigerant must be
ordered separately, and installed prior to operating the
system.
This instruction is specifically for the following model
voltage configurations:
S M Voltage 380/420VAC, 3−Phase, 50 Hertz
S T Voltage 220/240VAC, 1−Phase, 50 Hertz
Page 1
Specifications and Electrical Data1
SPECIFICATIONS − SINGLE PHASE
General
Data
Model No. TPA024S4 TPA036S4 TPA048S4
Nominal kW 7 10.5 14.0
Connections
(sweat)
Liquid line o.d. − in. 3/8 3/8 3/8
Vapor line o.d. − in. 3/4 7/8 7/8
1
Refrigerant (R−410A) furnished 2.95 kg (6 lbs. 8 oz.) 2.86 kg (6 lbs. 5 oz.) 5.30 kg (11 lbs. 11 oz.)
Outdoor
Coil
Net face area
2
m
(sq. ft.)
Outer coil 1.41 (15.21) 1.41 (15.21) 1.96 (21.11)
Inner coil − − − 1.44 (15.50) 1.98 (21.31)
Tube diameter − in. 5/16 5/16 5/16
Number of rows 1 2 2
Fins per meter (inch) 866 (22) 866 (22) 866 (22)
Outdoor
Fan
Diameter − mm (in.) 457 (18) 457 (18) 559 (22)
Number of blades 3 4 4
Motor W (hp) 149 (1/5) 149 (1/5) 248 (1/3)
L/s (Cfm) 945 (2000) 965 (2042) 1530 (3242)
Rev / min 942 917 904
Watts 138 158 313
Shipping Data − kg (lbs.) 1 package 64 (140) 82 (180) 113 (250)
Electrical Data
Line voltage data − 50 hz − 1ph 220 / 240V 220 / 240V 220 / 240V
2
Maximum overcurrent protection (amps) 25 35 35
3
Minimum circuit ampacity 14.7 21.1 21.6
Compressor Rated load amps 10.9 16.0 15.9
Locked rotor amps 60.0 87.0 98.0
Outdoor
Fan Motor
Locked rotor amps 1.9 1.9 4.1
NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage.
1
Refrigerant charge sufficient for 4.6 m (15 ft.) length of refrigerant lines.
2
Heating Air Conditioning and Refrigeration type circuit breaker or fuse.
3
Refer to local codes to determine wire, fuse and disconnect size requirements.
Power factor 1.1 1.1 1.7
Full load amps 2.0 2.0 4.1
Page 2
SPECIFICATIONS − THREE PHASE
General
Data
Model No. TPA036S4 TPA048S4 TPA060S4
Nominal kW 10.5 14.0 17.6
Connections
(sweat)
Liquid line o.d. − in. 3/8 3/8 3/8
Vapor line o.d. − in. 7/8 7/8 1−1/8
1
Refrigerant (R−410A) furnished 2.86 (6 lbs. 5 oz.) 5.30 (11 lbs. 11 oz.) 6.24 (13 lbs. 12 oz.)
Outdoor
Coil
Net face area
2
m
(sq. ft.)
Outer coil 1.41 (15.21) 1.96 (21.11) 2.28 (24.50)
Inner coil 1.44 (15.50) 1.98 (21.31) 2.19 (23.56)
Tube diameter − in. 5/16 5/16 5/16
Number of rows 2 2 2
Fins per meter (inch) 866 (22) 866 (22) 866 (22)
Outdoor
Fan
Diameter − mm (in.) 457 (18) 559 (22) 559 (22)
Number of blades 4 4 4
Motor W (hp) 125 (1/6) 250 (1/3) 185 (1/4)
L/s (Cfm) 965 (2042) 1530 (3242) 1505 (3192)
Rev / min 917 904 692
Watts 158 313 275
Shipping Data − kg (lbs.) 1 package 82 (180) 113 (250) 116 (255)
Electrical Data
Line voltage data − 50 hz − 3ph 380 / 420V 380 / 420V 380 / 420V
2
Maximum overcurrent protection (amps) 10 10 15
3
Minimum circuit ampacity 8.0 8.6 10.7
Compressor Rated load amps 6.0 6.1 7.8
Locked rotor amps 46.0 43.0 51.5
Power factor 0.55 1.0 1.0
Outdoor
Fan Motor
Full load amps 1.1 2.2 2.3
Locked rotor amps 1.9 4.1 3.1
NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage.
1
Refrigerant charge sufficient for 4.6 m (15 ft.) length of refrigerant lines.
2
Heating Air Conditioning and Refrigeration type circuit breaker or fuse.
3
Refer to local codes to determine wire, fuse and disconnect size requirements.
OPTIONAL ACCESSORIES
For update−to−date information, see any of the following publications:
S Lennox TPA*S4 Engineering Handbook
S Lennox Commercial Price Book
Page 3
Unit Dimensions − inches (mm)2
A
Outdoor Coil Fan
Compressor
A
Discharge Air
BC
Electrical
Inlets
2 (51)
SIDE VIEW
Model No. A B C
TPA024S4N41T 24−1/4 (616) 33−1/4 (845) 32−1/2 (826)
TPA036S4N41M 24−1/4 (616) 33−1/4 (845) 32−1/2 (826)
TPA036S4N41T 28-1/4 (718) 37 (940) 36−1/4 (921)
TPA048S4N41M 28-1/4 (718) 37 (940) 36−1/4 (921)
TPA048S4N41T 28-1/4 (718) 37 (940) 36−1/4 (921)
TPA060S4N41M 28-1/4 (718) 43−1/4 (1099) 42−1/2 (1080)
3/4 (19)
Vapor and Liquid
Line Connections
2-3/4 (70)
Optional Unit
Stand-off Kit (4)
(Field−installed)
SIDE VIEW
Typical Control Panel Parts Arrangement3
CAPACITOR
GROUND LUG
CONTACTOR LOCATION
OR
THREE
PHASE
ONE
PHASE
CUTOUT FOR HIGH
VOLTAGE CONDUIT
CONTROL
DEFROST CONTROL BOARD
CONTROL WIRE LOOP
Page 4
Typical Unit Parts Arrangement4
NOTE: PLUMBING LAYOUT MAY VARY SLIGHTLY BETWEEN MODEL SIZES.
COMPRESSOR
HARNESS
DEFROST
THERMOSTAT
COMPRESS0R
DISCHARGE LINE
MUFFLER
CHECK EXPANSION
BI−FLOW FILTER DRIER
VALV E
EQUALIZER LINE
TRUE SUCTION PORT
HIGH PRESSURE SWITCH (S4)
LIQUID LINE SERVICE VALVE
LOW PRESSURE SWITCH
REVERSING VALVE
REVERSING VALVE SOLENOID
VAPOR LINE SERVICE VALVE
Model Number Identification5
Brand/Family
T = T−Classt Product Line
Unit Type
P = Split−System Heat Pump
Major Design Sequence
A = 1st Generation
B = 2nd Generation
TPA M1036 S 44 N
024 = 2 Ton
030 = 2.5 Tons
0036 = 3 Tons
048 = 4 Tons
060 = 5Tons
Cooling Efficiency
S = Standard Efficiency
Page 5
Voltage
M = 380/420V−3 phase 50hz
T = 220/240V−1 phase 50hz
Minor Design Sequence
1 = 1st Revision
2 = 2nd Revision
3 = 3rd Revision
Coil Type
4 = Four−sided
Part Load Capability
N = No part load, single stage compressor
Refrigerant Type
4 = R−410A
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are
subject to change. T hi s m anual is divided into sections
which discuss the major components, refrigerant
system, charging procedure, maintenance and
operation sequence.
Remove (7) screws
FAN GUARD
FAN
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.
Unit Components6
CONTROL BOX
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 color-coded
pigtail connections.
COMPRESSOR CONTACTOR K1
The compressor is energized by a contactor located in the
control box as illustrated on Page 4. One or three−pole
contactors are used in this model. K1 is energized by the
indoor thermostat terminal Y1 (24V) when thermostat
demand is present.
CONDENSER FAN MOTOR B4 AND CAPACITOR C1
This model use a one−phase PSC fan motors which require a
run capacitor C1 located in the control box. Ratings for
C1 will be on fan motor nameplate. In all units, the
condenser fan is controlled by the compressor
contactor.
ELECTRICAL DATA tables in this manual show
specifications for condenser fans used in this model.
Remove (4) nuts
MOTOR
RACEWAY
REMOVE (7) SCREWS
SECURING FAN GUARD.
REMOVE FAN GUARD/FAN AS-
SEMBLY.
WIRING
Figure 1. Condenser Fan Motor and Compressor
Access
ALIGN FAN HUB FLUSH WITH END OF SHAFT
Figure 2. Fan Hub Alignment.
HIGH PRESSURE SWITCH S4
The manual−reset high pressure switch is located in the
liquid line. When liquid line pressure exceeds the factory
setting of 590 + 10 psi, the switch opens and shuts off the
compressor.
LOSS OF CHARGE SWITCH S24 (FIELD
INSTALLED OPTION)
The loss of charge switch is N.C. auto re−set and located
on the liquid line of the compressor. The switch opens
when liquid line pressure drops to 25 + 5 psig and shuts off
the compressor. The switch closes on a pressure rise at 55
+ 5 psig. The settings are factory set and cannot be
adjusted.
Access to the condenser fan motor on all units is gained
by removing the seven screws securing the fan
assembly as illustrated in Figure 1. The condenser fan
motor is removed from the fan guard by removing the
four nuts found on the top panel. Drip loops should be
used in wiring when servicing motor. See Figure 1 if
condenser fan motor replacement is necessary.
CRANKCASE HEATER HR1 AND OPTIONAL
THERMOSTAT S40
Crankcase heater HR1 prevents liquid from accumulating
in the compressor. HR1 is controlled by optional 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°.
Page 6
SUCTION
DETAIL A
SUCTION
INTERMEDIATE PRESSURE
GAS
ORBITING SCROLL
STATIONARY SCROLL
SUCTION
POCKET
SUCTION
DETAIL C
HIGH PRESSURE GAS
FLANKS SEALED
BY CENTRIFUGAL
MOVEMENT OF ORBIT
Figure 3. Scroll Compressors
REVERSING VALVE L1 AND SOLENOID
A refrigerant reversing valve with electromechanical
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.
FORCE
DETAIL D
DISCHARGE
CRESCENT
SHAPED
GAS POCKET
DETAIL B
SUCTION
DISCHARGE
POCKET
If replacement is necessary, access reversing valve by
removing the outdoor fan motor. Refer to figure 1.
BI−FLOW DRIER
A filter drier designed for all TPA4*S4 model units is
located in the liquid line. The field installed drier is designed
to remove moisture, which can lead to compressor failure.
Any time unit is exposed to open air due to service,
drier must be replaced. All replacement driers must be
approved for HFC−410A refrigerant.
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
illustrated in Figure 4. 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. Two identical scrolls are mated together forming
concentric spiral shapes as illustrated in Figure 5. One scroll
remains stationary, while the other is allowed to orbit. Note
that the orbiting scroll does not rotate or turn but merely orbits
the stationary scroll.
NOTE − During operation, the head of a scroll compressor
may be hot since it is in constant contact with discharge gas.
SUCTION
Figure 4. Scroll Compressor
DISCHARGE
DISCHARGE
PRESSURE
TIPS SEALED BY
DISCHARGE PRESSURE
Figure 5. Scroll Cross−Section
STATIONARY SCROLL
SUCTION
ORBITING SCROLL
Page 7
The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls as
illustrated in Figure 3, detail A. The centrifugal action of the
orbiting scroll seals off the flanks of the scrolls as illustrate din
Figure 3, detail B. As the orbiting motion continues, the gas is
forced toward the center of the scroll and the gas pocket
becomes compressed as illustrated in Figure 3, detail C.
When the compressed gas reaches the center, it is
discharged vertically into a chamber and discharge port in the
top of the compressor as illustrate in Figure 5. The discharge
pressure forcing down on the top scroll helps seal off the
upper and lower edges (tips) of the scrolls as illustrated in
Figure 5. During a single orbit, several pockets of gas are
compressed simultaneously providing smooth continuous
compression.
IMPORTANT
Only use Allen wrenches of sufficient hardness (50Rc −
Rockwell Harness Scale minimum). Fully insert the
wrench into the valve stem recess.
Service valve stems are factory−torqued (from 9 ft−lbs for
small valves, to 25 ft−lbs for large valves) to prevent
refrigerant loss during shipping and handling. Using an
Allen wrench rated at less than 50Rc risks rounding or
breaking off the wrench, or stripping the valve stem
recess.
See the Lennox Service and Application Notes #C−08−1
for further details and information.
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 to pump system into a
vacuum. 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 or ELECTRICAL DATA for
compressor specifications.
General Information7
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
who have jurisdiction before installation.
Operating Gauge Set and Service Valves8
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
who have jurisdiction before installation.
TORQUE REQUIREMENTS
When servicing or repairing heating, ventilating, and air
conditioning components, ensure the fasteners are
appropriately tightened. Table 1 lists torque values for
fasteners.
IMPORTANT
To prevent stripping of the various caps used, the
appropriately sized wrench should be used and fitted
snugly over the cap before tightening.
When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened. Table 1 provides
torque values for fasteners.
Table 1. Torque Requirements
Parts Recommended Torque
Service valve cap 8 ft.− lb. 11 NM
Sheet metal screws 16 in.− lb. 2 NM
Machine screws #10 28 in.− lb. 3 NM
Compressor bolts 90 in.− lb. 10 NM
Gauge port seal cap 8 ft.− lb. 11 NM
USING MANIFOLD GAUGE SET
When checking the system charge, only use a manifold
gauge set that features low loss anti−blow back fittings.
Manifold gauge set used with HFC−410A refrigerant
systems must be capable of handling the higher system
operating pressures. The gauges should be rated for use
with pressures of 0 − 800 psig on the high side and a low
side of 30" vacuum to 250 psig with dampened speed to
500 psi. Gauge hoses must be rated for use at up to 800
psig of pressure with a 4000 psig burst rating.
OPERATING SERVICE VALVES
The liquid and vapor line service valves are used for
removing refrigerant, flushing, leak testing, evacuating,
checking charge and charging.
Each valve is equipped with a service port which has a
factory−installed valve stem. Figure 6 provides information
on how to access and operating both angle and ball service
valves.
Page 8
SERVICE VALVES
VARIOUS TYPES
OPEN TO BOTH INDOOR AND
OUTDOOR UNITS
SERVICE PORT CAP
SERVICE PORT
TO INDOOR
CORE
UNIT
SERVICE PORT
(VALVE STEM
SHOWN OPEN)
INSERT HEX
WRENCH HERE
STEM CAP
SERVICE PORT CAP
SERVICE PORT
CORE
VALVE STEM
FRONT-SEATED
TO INDOOR
UNIT
TO OUTDOOR
UNIT
SERVICE VALVE
(FRONT−SEATED
STEM CAP
ANGLE−TYPE
CLOSED)
SERVICE PORT
(VALVE STEM SHOWN
CLOSED) INSERT HEX
WRENCH HERE
CLOSED TO BOTH
INDOOR AND OUTDOOR
UNITS
TO INDOOR UNIT
TO OUTDOOR UNIT
WHEN SERVICE VALVE IS CLOSED, THE SERVICE PORT IS OPEN TO THE
LINE SET AND INDOOR UNIT.
WHEN SERVICE VALVE IS OPEN, THE SERVICE PORT IS OPEN TO LINE SET,
INDOOR AND OUTDOOR UNIT.
ANGLE−TYPE SERVICE VALVE
(BACK−SEATED OPENED)
TO OPEN ROTATE STEM
COUNTERCLOCKWISE 90°.
TO CLOSE ROTATE STEM
CLOCKWISE 90°.
SERVICE PORT
SERVICE PORT CORE
SERVICE PORT CAP
To Access Service Port:
A service port cap protects the service port core from contamination and
serves as the primary leak seal.
1. Remove service port cap with an appropriately sized wrench.
2. Connect gauge set to service port.
3. When testing is completed, replace service port cap and tighten as fol lows:
S With Torque Wrench: Finger tighten and torque cap per Table 1.
S Without Torque Wrench: Finger tighten and use an appropriately
sized wrench to turn an additional 1/6 turn clockwise.
TO OUTDOOR UNIT
12
11
10
9
8
7
6
1/6 TURN
1
2
3
4
5
Operating Angle Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use a service wrench with a hex−head extension (3/16" for liquid line valve sizes and 5/16" for vapor line valve
sizes) to back the stem out counterclockwise as far as it will go.
BALL (SHOWN CLOSED)
BALL−TYPE SERVICE
VAL VE
VALVE STEM
STEM CAP
Operating Ball Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use an appropriately sized wrenched to open. To open valve, rotate stem counterclockwise 90°. To close rotate stem clockwise 90°.
Reinstall Stem Cap:
Stem cap protects the valve stem from damage and serves as the primary seal. Replace the stem cap and
tighten as follows:
S With Torque Wrench: Finger tighten and then torque cap per Table 1.
S Without Torque Wrench: Finger tighten and use an appropriately sized wrench to turn
an additional 1/12 turn clockwise.
NOTE A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque.
Figure 6. Angle and Ball Service Valves
Page 9
9
10
8
11
1/6 TURN
12
1
2
3
4
5
7
6
Recovering Refrigerant from Existing System9
RECOVERING
REFRIGERANT FROM SYSTEM
DISCONNECT POWER
Disconnect all power to the existing outdoor unit at the disconnect
1
switch or main fuse box/breaker panel.
MAIN FUSE BOX/BREAKER PANEL
SERVICE
DISCONNECT
SWITCH
RECOVERING REFRIGERANT
Remove existing HCFC−22 refrigerant using one of the following procedures:
3
IMPORTANT Some system configurations may contain higher than normal refrigerant charge due to either large internal coil volumes,
and/or long line sets.
CONNECT MANIFOLD GAUGE SET
Connect a gauge set, clean recovery cylinder and a recovery
2
machine to the service ports of the existing unit. Use the
instructions provided with the recovery machine to make the
connections.
MANIFOLD GAUGES
RECOVERY MACHINE
LOW
CLEAN RECOVERY
CYLINDER
OUTDOOR UNIT
HIGH
METHOD 1:
Us this method if the existing outdoor unit is not equipped with shut−off valves, or if the unit is not operational and you plan to use the existing
HCFC−22 to flush the system.
Remove all HCFC−22 refrigerant from the existing system. Check gauges after shutdown to confirm that the entire system is completely void of
refrigerant.
METHOD 2:
Use this method if the existing outdoor unit is equipped with manual shut−off valves, and you plan to use new HCFC−22 refrigerant to flush the
system.
The following devices could prevent full system charge recovery into the outdoor unit:
S Outdoor unit’s high or low−pressure switches (if applicable) when tripped can cycle the compressor OFF.
S Compressor can stop pumping due to tripped internal pressure relief valve.
S Compressor has internal vacuum protection that is designed to unload the scrolls (compressor stops pumping) when the pressure ratio meets
a certain value or when the suction pressure is as high as 20 psig. (Compressor suction pressures should never be allowed to go into a vacuum.
Prolonged operation at low suction pressures will result in overheating of the scrolls and permanent damage to the scroll tips, drive bearings and
internal seals.)
Once the compressor can not pump down to a lower pressure due to one of the above system conditions, shut off the vapor valve. Turn OFF the
main power to unit and use a recovery machine to recover any refrigerant left in the indoor coil and line set.
Perform the following task:
A Start the existing HCFC−22 system in the cooling mode and close the liquid line valve.
B Use the compressor to pump as much of the existing HCFC−22 refrigerant into the outdoor unit until the outdoor system is full. Turn the outdoor unit
main power OFF and use a recovery machine to remove the remaining refrigerant from the system.
NOTE It may be necessary to bypass the low pressure switches (if equipped) to ensure complete refrigerant evacuation.
C When the low side system pressures reach 0 psig, close the vapor line valve.
D Check gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system.
Page 10
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