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Preliminary Oil Charge —
charged with oil (see Table 1A or 1B). When oil is checked at
start-up, it may be necessary to add or remove oil to bring it to
the proper level. One recommended oil level adjustment
method is as follows:
ADD OIL — Close suction service valve and pump down
crankcase to 2 psig (14 kPag). Wait a few minutes and repeat
until pressure remains steady at 2 psig (14 kPag). Remove oil
fill plug above the sight glass, add oil through plug hole, and
replace plug. Run compressor for 20 minutes and check oil
level.
NOTE: Use only Carrier approved compressor oil. Approved
sources are:
Petroleum Specialties Inc. . . . . . . . . . . . . . . . . . . . . Cryol 150A
Texaco, Inc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Capella WF-32
Witco Chemical Co.. . . . . . . . . . . . . . . . . . . . . . . . . Suniso 3GS
Do not use oil that has been drained out, or oil that has been
exposed to atmosphere.
REMOVE OIL — Pump down compressor to 2 psig
(14 kPag). Loosen the ¼-in. pipe plug at the compressor base
and allow the oil to seep out past the threads of the plug.
Retighten plug when level is correct.
NOTE: The crankcase is slightly pressurized. Do not remove
the plug, or the entire oil charge will be lost.
Small amounts of oil can be removed through the oil pump
discharge connection while the compressor is running.
Start Unit —
Close the field disconnect and set the space
thermostats above ambient temperature so that there is no
demand for cooling. Only the crankcase heaters will be
energized.
Next, close the compressor circuit breakers. Place thermo-
stat selector switch at COOL and set space set point below am-
bient temperature so that a call for cooling is ensured. If com-
pressor does not start, set thermostat lower.
NOTE: Do not use circuit breaker to start and stop the com-
pressor except in an emergency.
Never charge liquid into the low-pressure side of system.
Do not overcharge. During charging or removal of refriger-
ant, be sure indoor-fan system is operating.
Adjust Refrigerant Charge
NOTE: The remaining start-up procedures and all refrigerant
charge modifications should be done only under supervision of
a qualified refrigeration mechanic.
With all fans operating, and compressor operating fully
loaded, adjust the refrigerant charge in accordance with the
unit charging charts located on the inside of the control box
doors and in Fig. 12 and 13.
Charge unit on cooling cycle only. If unit is charged on
heating cycle, overcharging may occur.
1. Be sure to use Refrigerant-22.
2. Regulate refrigerant drum valve to maintain suction pres-
sure at 80 psig (550 kPag) while charging. Charge with
vapor only, at suction side of unit.
NOTE: Do not depend on sight glass when charging unit.
Use charging chart.
3. Allow system to operate for 20 minutes. Take tempera-
ture and pressure readings at liquid line service valve and
check values with the charging chart.
The compressor is factory
Fig. 12 — Cooling Cycle Charging Chart,
Fig. 13 — Cooling Cycle Charging Chart,
4. Plot point on charging chart. If point is above curve, add
charge. If point is below curve, reduce charge until point
falls on line.
5. Record the final refrigerant charge.
If the sight glass is cloudy, check refrigerant charge again.
Ensure all fans are operating. Also ensure maximum allowable
liquid lift has not been exceeded. If charged per chart and if the
sight glass is still cloudy, check for a plugged filter drier or a
partially closed solenoid valve. Replace or repair, as needed.
Check Heating Cycle Operation —
stat selector switch at HEAT and reset the space set point
above ambient temperature so that a call for heating is
ensured. Compressor will start within 5 minutes. Observe
system operation.
Check Compressor Oil Level —
refrigerant charge, allow the system to run fully loaded for
20 minutes. Running oil level should be within view in the
crankcase sight glass. Stop compressor at the field power
16
38AQS012
38AQS016
Place thermo-
After adjusting the
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