• SUCTION PIPING AT INDOOR COIL AND
TXV SENSING BULB LOCATION
Step 4 — Make Electrical Connections .......3
• FIELD POWER SUPPLY
• ACCESSORY ELECTRIC HEAT
• FIELD CONTROL WIRING
START-UP ...............................10,11
Preliminary Checks ........................10
Evacuate and Dehydrate ...................10
Refrigerant Charge ........................ 10
Refrigerant Service Ports ..................10
Sequence of Operation ....................10
Checking Cooling and Heating Control
Operation ...............................11
Malfunction ...............................11
SERVICE .................................11-13
Cleaning ..................................11
Lubrication ................................11
Outdoor-Fan Adjustment ...................11
Compressor Removal ......................11
Cooling Mode Operation ...................12
Heating Mode Operation ...................12
TROUBLESHOOTING CHART ..............14,15
START-UP CHECKLIST ................CL-1,CL-2
38AQS008
Air-Cooled Split System Heat Pump
50/60 Hz
Before installing or servicing system, always turn off
main power to system. There may be more than one disconnect switch. Electrical shock can cause personal
injury.
INSTALLATION
The 38AQS008 unit uses a semi-hermetic compressor. See
Tables 1A and 1B for physical data.
The 38AQS008 is approved by Carrier for use only with
40RMQ008 fan cooling units. Use only approved far coils.
The 38AQS008 (60 Hz) is Underwriters’Laboratories (UL)
and Canadian Underwriters’ Laboratories (CUL) approved
for use with the 40RMQ008 fan coil only.
Step 1 — Complete Pre-Installation Checks
UNCRATE UNIT (See Fig. 1) — Remove unit packaging
except for the top skid assembly and wood bumpers, which
should be left in place until after unit is rigged into place.
INSPECT SHIPMENT — File claim with shipping company if shipment is damaged or incomplete.
SAFETY CONSIDERATIONS
Installing and servicing air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only trained and qualified service personnel should
install or service air-conditioning equipment.
When working on air-conditioningequipment,observeprecautions in literature and on tags and labels attached to unit.
Follow all safety codes. Wearsafety glasses and work gloves.
Use quenching cloth for brazing operations. Have fire extinguisher available. Read these instructions thoroughly.Consult local building codes and National Electrical Code U.S.A.
(NEC) for special installation requirements.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Ta b 5a 5 a
PC 111Catalog No. 533-887Printed in U.S.A.Form 38AQS-4SIPg 16-95Replaces: 38AQS-3SI
NEMA — National Electrical Manufacturing Association (U.S.A.)
*Unit is factory supplied with holding charge only.
†Storage capacity of coil with coil 80% full of liquid R-22 at 49 C.
**All pipe sizes are OD inches; equivalent sizes in millimeters follow:
2
)1.67
Cut-in2206 ⫾ 138
Cut-in151 ⫾ 34
LEGEND
in.mm
1
⁄
11⁄
2
8
12.7
28.6
3
⁄
4
Aluminum Lanced Fins
1
⁄
3
1
⁄
8
1
⁄
2
CONSIDER SYSTEM REQUIREMENTS
• Consult local building codes and NEC (U.S.A.) for special installation requirements.
• Allow sufficient space for airflow clearance, wiring, refrigerant piping, and servicing unit. See Fig. 2.
• Locate unit so that outdoor unit airflow is unrestricted on
all sides and above. Refer to Fig. 2.
• Unit may be mounted on a level pad directly on base rails
or mounted on raised pads at support points. See Fig. 2 for
weight distribution based on recommended support points.
• Provide for condensate drainage and defrost water disposal beneath unit.
• Areas with high snowfall may need elevated mounting for
adequate airflow.
NOTE: If vibration isolators are required for a particular installation, use corner weight information in Fig. 2 to make
proper selection.
Step 2 — Rig and Mount the Unit
Be sure unit panels are securely in place prior to
rigging.
RIGGING — These units are designed for overhead rigging. Refer to rigging label for preferred rigging method.
Spreader bars are not required if top crating is left on unit.
All panels must be in place when rigging. (See Fig. 3.) As
further protection for coil faces, plywood sheets may be placed
against sides of unit, behind cables. Run cables to a central
suspension point so that angle from the horizontal plane is
not less than 45 degrees. Raise and set unit down carefully.
If it is necessary to roll unit into position, mount unit on
rails, using a minimum of 3 rollers. Apply force to rails, notunit. If unit is to be skidded into position, place it on a large
pad and drag it by the pad. Do not apply any force to unit.
Raise from above to lift unit from rails or pad when unit
is in final position.
After unit is in position, remove all shipping wrapping and
top crating.
MOUNTING — The unit must be elevated to ensure drainage from basepan during sub-freezing conditions and to prevent or limit blockage of outdoor coil during snowfall. Consideration should be given to specific geographical areas when
determining height of unit elevation.
COMPRESSOR MOUNTING — As shipped, compressors
are held down by 4 bolts. After unit is installed, loosen each
bolt until the snubber washer can be moved with finger pressure. See Fig. 4.
uid connection is sweat with plastic cap. Refer to Table2 for
the proper line sizes. Follow standard piping practices.
Suction connection is sweat with plastic cap; liq-
2
Page 3
Table 2 — Refrigerant Piping Sizes
LINEAR LENGTH OF PIPING — ft (m)
0-25
UNIT
38AQS
→
008
L—Liquid LineOD — Outside DiameterS—Suction Line
NOTES:
1. Pipe sizes are based on a 2° F (1° C) loss for liquid and suction
lines.
2. Pipe sizes are based on the maximum linear length shown for each
column, plus a 50% allowance for fittings.
3. Charge units with R-22 in accordance with unit installation
instructions.
4. Line size conversion to mm is:
(0-7.6)
LSLSLSLS
1
⁄211⁄
in.mm
1
⁄
2
5
⁄
8
3
⁄
4
11⁄
8
13⁄
8
8
25-50
(7.6-15.2)
Line Size (in. OD)
5
⁄811⁄
8
LEGEND
12.7
15.9
19
28.6
34.9
50-75
(15.2-22.9)
5
⁄
8
11⁄
8
75-100
(22.9-30.5)
5
⁄
8
SIZE REFRIGERANT LINES — Consider length of piping
required between 38AQS unit and 40RMQ unit, amount of
liquid lift, and compressor oil return. See Table 3 and also
refer to Part 3 of Carrier System Design Manual for design
details and line sizing. Refer to 40RMQ installation instructions for additional information.
Table 3 — Liquid Line Data
MAX
ALLOWABLE
UNIT
38AQS
00875 22.9 65 19.874821
1. The liquid lift in cooling mode is based on 80/67 F (22.7/19.4 C)
(db/wb [dry bulb/wet bulb]) entering indoor-air temperature and a
95 F (35 C) outdoor-air temperature, with R-22 refrigerant, at an
indoor airflow of 3000 cfm (1416 L/s).
2. The liquid lift in heating mode is based on 70/60 F (21.1/15.6 C)
(db/wb) entering indoor-air temperature and a 47/43 F (8.3/6.1 C)
(db/wb) outdoor-air temperature, with R-22 refrigerant, at an indoor airflow of 3000 cfm (1416 L/s).
LIQUID LIFT
HeatingCooling
ftmftmpsikPaFC
Max Allowable
Pressure Drop
LIQUID LINE
Max Allowable
Temp Loss
FILTER DRIER AND MOISTURE INDICATOR — See
Fig. 5. The filter drier is factory supplied and field-installed
in the liquid line. Moisture indicator is field-supplied and
should be installed just after liquid line shutoff valve. Do notuse a receiver; there is none provided with unit and one should
not be used.
NOTE: Unit is shipped with R-22 holding charge. System
pressure must be relieved before removing caps. Recover refrigerant prior to brazing.
Pass nitrogen or other inert gas through piping while braz-
ing to prevent formation of copper oxide.
LIQUID LINE SOLENOID VALVE —A field supplied liq-
uid line solenoid valve (LLSV) is recommended when piping system length exceeds 75 ft (23 m). The LLSV must be
of the biflow type, suited for use in heat pump systems.
11⁄
NOTE: Carrier recommends part number EF23JS214 (Sporlan
model CB14S2,
5
⁄8-in. ODF/7⁄8-in. ODM) available from the
Replacement Components Division of Carrier Corporation.
This solenoid requires field supplied Sporlan MKC-2 coils.
Wire the solenoid in parallel with the compressor con-
tactor coil.
8
Install the LLSV near the outdoor unit. The flow arrow
must be pointed toward the outdoor unit.
SAFETY RELIEF — A fusible plug is located on top of the
accumulator. See Fig. 6. Note that all safety relief components are factory installed. Do not cap fusible plug. If local
code requires additional safety device(s), install as directed.
SUCTION PIPING AT INDOOR COIL AND TXV SENSING BULB LOCATION — To achieve good mixing of refrigerant leaving the indoor coil suction header for proper
sensing by the thermostatic expansion valve (TXV) bulb (see
Fig. 7):
1. A minimum of two 90-degree elbows should be installed
upstream of the TXV bulb location.
2. The TXV bulb should be located on a vertical riser where
possible. If a horizontal location is necessary, secure the
bulb at approximately the 4 o’clock position or the
8 o’clock position. See Fig. 7.
3. Enter suction pipe sizing charts in the Carrier System De-
sign Manual at design tons and equivalent length for
2° F (1° C) loss. If the reading falls between 2 sizes on
the chart, choose the smaller pipe size.
4. Make sure that the piping system has no inherent oil traps,
and the piping layout will not allow oil to migrate into an
idle evaporator coil.
5. Complete refrigerant piping from indoor coil to outdoor
coil before opening liquid and suction lines at the 38AQS
unit. See Tables 1A, 1B, and 2 for piping selection data.
Step 4 — Make Electrical Connections
Unit cabinet must have an uninterrupted, unbroken electrical ground to minimize the possibility of personal injury if an electrical fault should occur. This ground may
consist of electrical wire connected to unit ground lug
in control compartment, or conduit approved for electrical ground when installed in accordance with NEC
ANSI (American National Standards Institute, U.S.A.)/
NFPA (National Fire Protection Association, U.S.A.) 70
and local electrical codes. Failure to follow this warning could result in the installer being liable for personal
injury of others.
FIELD POWER SUPPLY — All units except 208/230-v
(60 Hz) units are factory wired for the voltage shown on the
nameplate. If the 208/230-v unit is to be connected to a 208-v
power supply, the transformer must be rewired by moving
the black wire from the 230-v orange wire on the transformer and connecting it to the 208-v red wire from the transformer. The end of the orange wire must then be
insulated.
Refer to unit label diagram for additional information. Short
wire leads (pigtails) are provided for field wire connections.
Use factory-supplied splices or UL approved copper/
aluminum connector.
When installing units, provide a disconnect per NEC
(U.S.A.).
4. Minimum clearance (local codes or jurisdiction may prevail):
a. Bottom to combustible surfaces, 0 in. (0 mm)
b. Outdoor coil, for proper airflow, 36 in. (914 mm) one side, 12 in.
(305 mm) the other. The side getting the greater clearance is optional.
c. Overhead, 60 in. (1524 mm) to assure proper outdoor-fan operation.
d. Between units, control box side, 42 in. (1067 mm) per National
Electrical Code (NEC, U.S.A.).
e. Between unit and ungrounded surfaces, control box side, 36 in.
(914 mm) per NEC (U.S.A.).
f. Between unit and block or concrete walls and other grounded surfaces,
control box side, 42 in. (1067 mm) per NEC (U.S.A.).
5. With the exception of the clearance for the outdoor coil as stated in
note 4b, a removable fence or barricade requires no clearance.
6. Units may be installed on combustible floors made from wood or Class A,
B, or C roof covering material.
7. Vertical center of gravity is approximately 40% of total unit height.
Fig. 2 — Dimensions
ELECTRICAL CONNECTIONS
CONNECTION SIZES
3
AA1
⁄8⬙ Dia. [35] Field Power Supply Hole
BB2⬙ Dia. [51] Power Supply Knock-Out
1
CC2
DD
⁄2⬙ Dia. [64] Power Supply Knock-Out
7
⁄8⬙ Dia. [22] Field Control Wiring Hole
SERVICE VALVE CONNECTIONS
UNITSUCTIONLIQUID
38AQS0081
1
⁄8⬙ [28.6]
1
⁄2⬙ [12.7]
4
Page 5
MAX WEIGHT
UNIT
38AQS008
60 Hz590 268 658 298
50 Hz644 292 712 323
w/Al
Coil
Lb Kg Lb Kgin.mmin. mm in.mm
w/Cu
Fig. 3 — Rigging Label
Coil
ABC
45.0 1143 38.5 989 43.5 1105
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate (also see
Table 4). Voltages between phases must be balanced within
2% and the current within 10%. Use the formula shown in
Table 4, Note 2, to determine the percent voltage imbalance.
Operation on improper line voltage or excessive phase imbalance constitutes abuse and may cause damage to electrical components. Such operation would invalidate any applicable Carrier warranty.
ACCESSORY ELECTRIC HEAT — If the system is to be
equipped with an accessory electric heater, refer to the
40RMQ008 installation instructions and Tables 5A and 5B.
FIELD CONTROL WIRING — Install a Carrier-approved
accessory thermostat assembly according to installation instructions included with the accessory.Locate thermostat assembly on a solid wall in the conditioned space to sense average temperature in accordance with thermostat installation
instructions. Carrier-approved thermostat is Part Number
HH07AT-171. Subbase is HH93AZ-188.
Route thermostat cable or equivalent single leads of colored wire from subbase terminals to low-voltage connections on unit (shown in Fig. 9) as described in Steps 1 through
3 below.
1. Connect thermostat wires to screw terminals of low-
voltage connection board.
2. Pass the control wires through the hole provided in the
corner post. (See Fig. 10.)
3. Feed wire through the raceway built into the corner post
to the 24-v barriers located on the left side of the control
box. The raceway provides the required clearance between the high- and low-voltage wiring.
Fig. 4 — Compressor Mounting
All field wiring must comply with NEC (U.S.A.) and lo-
cal requirements.
Install field wiring as follows:
1. Install conduit through side panel openings.
2. Install power lines to connections as shown in Fig. 8. Wrap
connections with electrical tape.
NOTE: 39 VA is available for field-installed accessories.
Control power requirement for heat pump outdoor unit is
36 VA(sealed). The factory-supplied control transformer is
75 VA.
NOTE: For wire runs, use the following insulated wire:
LENGTH
FtMAWGsq mm
0-500-15.235180.82
50-7515.2-22.935161.30
Over 75Over 22.935142.08
LEGEND
AWG — American Wire Gage
INSULATION
RATING (C)
SIZE
All wire larger than no. 18 AWG (American Wire Gage)
cannot be directly connected to the thermostat and will require a junction box and splice at the thermostat.
5
Page 6
LEGEND
NEC — National Electrical Code
TXV — Thermostatic Expansion Valve
*Accessory item.
†Field supplied.
NOTES:
1. All piping must follow standard refrigerant piping techniques. Refer to Carrier System Design Manual for details.
2. All wiring must comply with the applicable local and national codes.
3. Wiring and piping shown are general points-of-connection guides
only and are not intended for, or to include all details for, a specific
installation.
4. Liquid line solenoid valve (solenoid drop control) is recommended
to prevent refrigerant migration to the compressor. A biflow type
solenoid valve is required.
5. Filter drier must be of the biflow type, suitable for heat pump duty.
6. Internal factory-supplied TXV and bypass check valve not shown.
Fig.5—Typical Piping Diagram, 38AQS/40RMQ
6
Page 7
Table 4 — Electrical Data
UNIT
38AQS
FLA— Full Load Amps
HACR — Heating, Air Conditioning and Refrigeration
LRA— Locked Rotor Amps
MCA— Minimum Circuit Amps
NEC— National Electrical Code (U.S.A.)
OFM— Outdoor Fan Motor
RLA— Rated Load Amps
(60 Hz Only)(60 Hz Only)
NOTES:
1. In compliance with NEC requirements for multimotor and combi-
2. Unbalanced 3-Phase Supply Voltage
= 100 x
NOMINAL VOLTAGE
(V-Ph-Hz)
208/230-3-6018725431.51603.142.55045177
008
nation load equipment (refer to NEC Articles 430 and 440), the
overcurrent protective device for the unit shall be fuse or HACR
breaker.
Never operate a motor where a phase imbalance in supply voltage is greater than 2%.
1. MCA and MOCP values apply to both standard andalternate factorysupplied motors.
2. Electrical resistance heaters are rated at 240 v, 480 v, or 575 v. To
determine heater capacity (kW) at unit nameplate voltage, multiply 240-v, 480-v, or 575-v capacity by multipliers found in table
below.
MCA*MOCP*
→
UNIT
40RMQ
008
MCA— Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection (Amps)
*Sizes shown are for single-point connection of electric heat acces-
1. MCA and MOCP values apply to both standard andalternate factorysupplied motors.
2. Electrical resistance heaters are rated at 230 v or 400 v. To determine heater capacity (kW) at unit nameplate voltage, multiply
230-v or 400-v capacity by multipliers found in table below.
MCA*MOCP*
8988
Page 9
CORNER
POST
RACEWAYTHERMOSTAT
FIELD CONNECTION
POWER WIRING
CONNECTIONS
Fig. 6 — Fusible Plug Locations
LEGEND
TXV —
NOTE: The 8 o’clock position is shown above.
Thermostatic Expansion Valve
Fig. 7 — TXV Sensing Bulb Location
LEGEND
Cooling
C—
Heating
H—
Heater Relay
HR —
Indoor Fan Contactor
IFC —
→
Fig. 9 — Control Wiring Connections
LLSV —
SUPL —
TB—
Fig. 10 — Field Control Wiring Raceway
Liquid Line Solenoid
Val ve
Supplemental
Terminal Block
LEGEND
C—
NEC —
Contactor
National Electrical Code (U.S.A.)
Field Wiring
Factory Wiring
Splice Connection (Factory Supplied)
Fig. 8 — 38AQS008 Power Wiring Connections
9
2
801
Page 10
START-UP
Preliminary Checks
1. Check that all internal wiring connections are tight and
that all barriers, covers, and panels are in place.
2. Field electrical power source must agree with unit nameplate rating.
3. Ensure all service valves are open. Ensure all compressor
service valves are backseated.
4. Verify that compressor holddown bolts have been loosened and that flat/snubber washers can be rotated by finger pressure (snug, but not tight).
5. Verify compressor crankcase heater is securely in place.
Crankcase heater must operate for at least 24 hours before start-up.
6. Note that compressor oil level is visible in the sight glass.
7. Check for leaks in refrigerant system by using soap bubbles
and/or electronic leak detector.
8. Check voltage imbalance as shown in Table 4, Note 2.
9. Check that both outdoor and indoor units are properly
mounted in accordance with installation instructions and
applicable codes.
Evacuate and Dehydrate — Evacuate and dehydrate
entire refrigerant systemby use of the methods
described in Carrier GTAC II, Module 4, System
Dehydration.
Refrigerant Charge — Refer to Carrier GTACII, Mod-
ule 5, Charging Recovery, Recycling, and Reclamation.
NOTE: Use of a Carrier Totalclaim威 refrigeration recovery
unit is highly recommended when recovering refrigerant.
Unit panels must be in place when unit is operating dur-
ing charging procedure.
Unit is shipped with holding charge only. Weigh in 15 lb
(7 kg) of R-22 to start unit.
Fig. 11 — Cooling Charging Chart — 38AQS008
Do not reuse drained oil or use any oil that has been ex-
posed to atmosphere. Procedures for adding or removing oil
are given in Carrier’s Refrigerant Service Techniquesmanual.
If oil is added, run unit for additional 10 minutes. Stop
unit and check oil level. If level is still low, add oil only after
determining that piping system is designed for proper oil return and that system is not leaking oil.
Refrigerant Service Ports — Each unit system has 3
service ports: one on the suction line, one on the liquid line,
and one on the compressor discharge line. Be sure caps on
the ports are tight.
CHARGE COOLING — Use Cooling Charging Chart (see
Fig. 11). Varyrefrigerant until the conditions of the chart are
met. Note that charging chart is different from the type normally used. Chart is based on charging the units to the correct subcooling for the various operating conditions. Accurate pressure gage and temperature sensing device are required.
Connect the pressure gage to the service port on the liquid
line service valve. Mount the temperature sensing device on
the liquid line, close to the liquid line service valve, and insulate it so that outdoor ambient temperature does not affect
the reading. Indoor airflow must be within the normal operating range of the unit.
Operate unit a minimum of 15 minutes. Ensure pressure
and temperature readings have stabilized. Plot liquid pressure and temperature on chart and add or reduce charge to
meet curve. Adjust charge to conform with charging chart,
using liquid pressure and temperature to read chart.
OIL CHARGE (Tables 1A and 1B) — Allow unit to run for
about 20 minutes. Stop unit and check compressor oil level.
Add oil only if necessary to bring oil into view in sight glass.
Use only Carrier-approved compressor oil.
Approved oils are:
Suniso 3GS and WF32-150
Sequence of Operation — When power is supplied
to unit, the transformer (TRAN) is energized. The crankcase
heater is also energized.
COOLING — With the thermostat subbase in the cooling
position, and when the space temperature comes within
2° F (1° C) of the cooling set point, the thermostat makes
circuit R-O. This energizes the reversing valve solenoid (RVS)
and places the unit in standby condition for cooling.
As the space temperature continues to rise, the second stage
of the thermostat makes, closing circuit R-Y. When compressor time delay (5 ± 2 minutes) is completed, a circuit is
made to contactor (C ), starting the compressor (COMP) and
outdoor-fan motor (OFM). Circuit R-G is made at the same
time, energizing the indoor-fan contactor (IFC) and starting
the indoor-fan motor (IFM) after one-second delay.
When the thermostat is satisfied, contacts open, deenergizing C. The COMP, IFM, and OFM stop.
HEATING — On a call for heat, thermostat makes circuits
R-Y and R-G. When compressor time delay (5 ± 2 minutes)
is completed, a circuit is made to C, starting COMPand OFM.
Circuit R-G also energizes IFC and starts IFM after a 1-second
delay.
10
Page 11
Should room temperature continue to fall, circuit R-W is
made through second-stage thermostat bulb. If optional electric heat package is used, a relay is energized, bringing on
supplemental electric heat. When thermostat is satisfied, contacts open, deenergizing contactor and relay; motors and heaters deenergize.
DEFROST — Defrost board (DB) is a time and temperature
control, which includes a field-selectable time period between checks for frost (30, 50, and 90 minutes). Electronic
timer and defrost cycle start only when contactor is energized and defrost thermostat (DFT) is closed (below 28 F
[−2.2 C]).
Defrost mode is identical to Cooling mode, except outdoorfan motor (OFM) stops and a bank of supplemental electric
heat turns on to warm air supplying the conditioned space.
Defrost mode is terminated when the DFT reaches 65 F
(18.3 C).
Checking Cooling and Heating Control Operation —
tion as follows:
1. Place room thermostat SYSTEM switch in an OFF po-
2. Place SYSTEM switch in COOLposition and FANswitch
3. Place system switch in HEAT position. Set control above
4. When using an automatic changeover room thermostat,
Start and check the unit for proper control opera-
sition. Observe that blower motor starts when FAN switch
is placed in ON position and shuts down when F ANswitch
is placed in AUTO. position.
in AUTO. position. Set control below room temperature.
Observe that compressor,outdoor fan, and indoor fan motors start. Observe that cooling cycle shuts down when
control setting is satisfied.
room temperature. Observe that compressor, outdoor fan,
indoor fan motor, and electric heaters (if equipped) start.
Observe that heating cycle shuts down when control setting is satisfied.
place both SYSTEM and FAN switches in AUTO positions. Observe that unit operates in Cooling mode when
temperature control is set to ‘‘call for Cooling’’ (below
room temperature), and unit operates in Heating mode
when temperature control is set to ‘ ‘callfor heating’ ’(above
room temperature).
Cleaning — Inspect unit interior at the beginning of each
cooling season and as operating conditions require.
OUTDOOR COIL — Inspect coil monthly. Clean outdoor
coil annually and as required by location or outdoor-air
conditions.
Clean coil as follows:
1. Turn off unit power.
2. Remove and save top panel screws on outdoor unit.
3. Remove outdoor coil corner post. See Fig. 12. To hold
top panel open, place coil corner post between top panel
and side panel. See Fig. 13.
4. Remove bracket holding coil sections together at return
end of outdoor coil. Carefully separate the outer coil section 3 to 4 in. from the inner coil section. See Fig. 14.
5. Use a water hose or other suitable equipment to flush down
between the 2 coil sections to remove dirt and debris. Clean
the outer surfaces with a stiffbrush in the normal manner.
6. Reposition the outer coil section and secure the sections
together. Remove the coil corner post from between the
top panel and side panel. Install the coil corner post and
replace all screws removed in Step 2.
Lubrication
COMPRESSORS — Compressor has its own oil supply.Loss
of oil due to a leak in the system should be the only reason
for adding oil after the system has been in operation. See
Start-Up, Oil Charge section.
FAN MOTOR BEARINGS — Fan motor bearings are of
the permanently lubricated type. No further lubrication is
required.
Outdoor-Fan Adjustment (Fig. 15)
1. Shut off unit power supply.
2. Remove outdoor-fan assembly (grille, motor, motor cover,
and fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig. 15.
5. Tighten setscrews.
6. Replace outdoor-fan assembly.
Malfunction — The high-pressure switch, loss-of-
charge switch, and compressor overtemperature safety are
located in a Cycle-LOC™ circuit that prevents heat pump
operation if these safety devices are activated.
The lockout system can be reset by adjusting the thermostat to open the contacts (down for heating mode, up for cooling mode) deenergizing the Cycle-LOC circuitry. Compressor overcurrent protection is achieved with overload breakers
which are temperature sensitive and will automatically
reset.
Unit is equipped with a no-dump reversing valve circuit.
When unit is in cooling mode, reversing valve remains in
cooling position until a call for heating is requested by thermostat. When unit is in heating mode, reversing valve remains in heating position until there is a call for cooling.
SERVICE
When servicing unit, shut off all electrical power to unit
to avoid shock hazard or injury from rotating parts.
Compressor Removal — See Tables 1A and 1B for
compressor information. Follow safety codes and wear safety
glasses and work gloves.
1. Shut off power to unit. Remove unit access panel (front
of unit).
2. Remove refrigerant from system using refrigerant removal methods described in Carrier’s Refrigrant Service Techniques manual.
4. Remove bolts from discharge service valve and suction
flange.
Excessive movement of copper lines at compressor may
cause higher levels of vibration when unit is restored to
service.
11
Page 12
5. Remove crankcase heater from compressor base.
6. Remove compressor holddown bolts and lift compressor off basepan.
7. Remove compressor from unit.
8. Clean system. Add new liquid line filter drier (biflow
type).
9. Install new compressor and position in unit. Connect suction and discharge lines to compressor. Connect high pressure switch. Ensure that compressor holddown bolts are
in place. Connect wiring. Install crankcase heater.
10. Evacuate and recharge unit.
11. Restore unit power.
Cooling Mode Operation — See Fig. 16.
1. Hot refrigerant gas from compressor flows through the
reversing valve and is directed to the outdoor coil vapor
header.
2. Once at the outdoor coil vapor header, hot refrigerant gas
flows up to check valve ⬙A,⬙ which is closed. All refrigerant is then directed to complete a path through the lower
6 coil circuits (6 passes in each circuit).
3. Refrigerant flows through from the liquid header side outlets into the transfer header, where it flows upward.
4. Refrigerant leaves the transfer header through side connections in 4 locations and enters the middle coil circuits
(4 coil circuits above check valve ⬙A⬙).
5. Refrigerant leaves the 4 middle coil circuit and enters the
top portion of vapor header. The refrigerant moves up to
the top 2 remaining coil circuits, where it enters the subcooler section.
Fig. 14 — Separating Coil Sections
Fig. 12 — Cleaning Outdoor Coil
Fig. 13 — Propping Up Top Panel
Fig. 15 — Outdoor-Fan Adjustment
6. Subcooled refrigerant leaves the coil circuits through the
side outlets. It passes through check valve ⬙B⬙ into the
system liquid line and then into the indoor coil.
7. Liquid refrigerant is expanded and evaporated to a lowpressure vapor in the indoor coil. Refrigerant vapor then
returns to the outdoor unit through the system vapor line,
where it is drawn through the reversing valve and accumulator and back to the compressor suction connection.
Heating Mode Operation — See Fig. 17.
1. Hot gas from compressor flows through the reversing valve
and is directed to the system vapor line and indoor coil
vapor header (not shown). Refrigerant is condensed and
subcooled in the indoor coil and returns to the outdoor
unit through the system liquid line.
2. Check valve ⬙B⬙ is closed and all liquid refrigerant enters
the liquid header.
3. Refrigerant leaves the liquid header through 12 locations. It is then expanded in fixed orifice metering devices contained within the outlet tubes.
4. Refrigerant evaporates to low pressure vapor as it completes its passage through the 12 parallel coil circuits (6
passes each).
5. Refrigerant moves from the coil circuits into the vapor
header, where it is drawn through the reversing valve and
accumulator and back to compressor suction connection.
12
Page 13
Fig. 16 — Cooling Mode Operation
Fig. 17 — Heating Mode Operation
13
Page 14
LEGEND
TXV — Thermostatic Expansion Valve
TROUBLESHOOTING CHART, COOLING CYCLE
14
Page 15
LEGEND
N.C. — Normally Closed
TROUBLESHOOTING CHART, HEATING CYCLE
15
Page 16
Page 17
Page 18
Copyright 1995 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Ta b 5 a 5 a
PC 111Catalog No. 533-887Printed in U.S.A.Form 38AQS-4SIPg 188016-95Replaces: 38AQS-3SI
Page 19
START-UP CHECKLIST
A. Preliminary Information
OUTDOOR: MODEL NO.SERIAL NO.
INDOOR: AIR HANDLER MANUFACTURER
MODEL NO.SERIAL NO.
ADDITIONAL ACCESSORIES
B. Pre-Start-Up
OUTDOOR UNIT
IS THERE ANY SHIPPING DAMAGE?
IF SO, WHERE:
WILL THIS DAMAGE PREVENT UNIT START-UP?(Y/N)
CHECK POWER SUPPLY. DOES IT AGREE WITH UNIT?(Y/N)
HAS THE GROUND WIRE BEEN CONNECTED?(Y/N)
HAS THE CIRCUIT PROTECTION BEEN SIZED AND INSTALLED PROPERLY?(Y/N)
ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY?(Y/N)
HAVE COMPRESSOR HOLDDOWN BOLTS BEEN LOOSENED (Snubber washers are snug, but not tight)?
(Y/N)
(Y/N)
CONTROLS
ARE THERMOSTAT AND INDOOR-FAN CONTROL WIRING
CONNECTIONS MADE AND CHECKED?(Y/N)
ARE ALL WIRING TERMINALS (including main power supply) TIGHT?(Y/N)
HAS CRANKCASE HEATER BEEN ENERGIZED FOR 24 HOURS?(Y/N)
INDOOR UNIT
HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE?(Y/N)
ARE PROPER AIR FILTERS IN PLACE?(Y/N)
HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT?(Y/N)
DO THE FAN BELTS HAVE PROPER TENSION?(Y/N)
HAS CORRECT FAN ROTATION BEEN CONFIRMED?(Y/N)
PIPING
IS LIQUID LINE SOLENOID VALVE LOCATED AT THE OUTDOOR UNIT AS RECOMMENDED?(Y/N)
HAVE LEAK CHECKS BEEN MADE AT COMPRESSOR, OUTDOOR COIL, INDOOR COIL, TXV (Thermostatic Expansion
Valve), SOLENOID VALVES, FILTER DRIER, REVERSING VALVE, CHECK VALVE, AND FUSIBLE PLUGS WITH A
LEAK DETECTOR?(Y/N)
LOCATE, REPAIR, AND REPORT ANY LEAKS.
HAVE ALL COMPRESSOR SERVICE VALVES BEEN FULLY OPENED (BACKSEATED)?(Y/N)
HAVE LIQUID LINE SERVICE VALVE AND SUCTION LINE SERVICE VALVE BEEN OPENED?(Y/N)
IS THE OIL LEVEL IN COMPRESSOR CRANKCASE INTO VIEW IN THE COMPRESSOR SIGHT GLASS?
(Y/N)
CHECK VOLTAGE IMBALANCE
LINE-TO-LINE VOLTS:AB
(AB + AC + BC)/3 = AVERAGE VOLTAGE =
MAXIMUM DEVIATION FROM AVERAGE VOLTAGE =
VOLTAGE IMBALANCE = 100 X (MAX DEVIATION)/(AVERAGE VOLTAGE) =
IF OVER 2% VOLTAGE IMBALANCE, DO NOT ATTEMPT TO START SYSTEM!
CALL LOCAL POWER COMPANY FOR ASSISTANCE.
VAC VBC V
V
V
CL-1
%
Page 20
C. Start-Up
CHECK INDOOR-FAN SPEED AND RECORD.
CHECK OUTDOOR-FAN SPEED AND RECORD.
AFTER AT LEAST 15 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:
OIL PRESSURE
SUCTION PRESSURE
SUCTION LINE TEMP
DISCHARGE PRESSURE
DISCHARGE LINE TEMP
ENTERING OUTDOOR-AIR TEMP
LEAVING OUTDOOR-AIR TEMP
INDOOR ENTERING-AIR DB (dry bulb) TEMP
INDOOR ENTERING-AIR WB (wet bulb) TEMP
INDOOR LEAVING-AIR DB TEMP
INDOOR LEAVING-AIR WB TEMP
COMPRESSOR AMPS (L1/L2/L3)
NOTES:
COOLING
HEATING
//
Copyright 1995 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Ta b5 a 5 a
PC 111Catalog No. 533-887Printed in U.S.A.Form 38AQS-4SIPg CL-28016-95Replaces: 38AQS-3SI