Pre-Start-Up; Evacuate And Dehydrate; Leak Test; Turn On Crankcase Heaters - Carrier 38AF Series Installation Manual

Evacuate and Dehydrate the entire refrigerant system by either of the methods described in Carrier
Standard Service Techniques Manual, Chapter 1.
Leak Test the entire refrigerant system by the pressure method described in Carrier Standard Service
Techniques Manual, Chapter l. Use R-22 at approximately 25 psig (172.4 kPa) backed up with an inert
gas to a total pressure not to exceed 245 psig (1689 kPa).
Turn on Crankcase Heaters for 24 hours before starting the unit to be sure all the refrigerant is
out of the oil. To energize the crankcase heaters, proceed as follows.
1. Set the space thermostat set point above the space temperature so there is no demand for
cooling.
2. Close the field disconnect
3. Turn the fan circuit breaker on. Leave the compressor circuit breakers off. The crankcase
heaters are now energized.
Add Preliminary Charge to the refrigerant system accordingly to Carrier Standard Service Techniques
Manual, Chapter l. By the liquid charging method and charging by weight procedure, charge the units
with approximately the amounts of R-22 refrigerant shown in table l. Physical Data.
Before Starting Unit ensure the following:
1. Compressor oil level must be at least within sight in the compressor sight glass. Add oil if
necessary (see Tables l).
2. Compressor hold down bolts must be snug, but not tight.
Refer to Compressor Mounting section and tag on compressor foot.
3. All internal wiring connections must be tight; all barriers and covers must be in place.
4. Electrical power source must agree with unit nameplate rating .
5. All service valves must be open.
6. Crankcase heater must be firmly locked into the compressor crankcase.
To Start Unit – Set thermostat set point
below the space temperature. After starting
unit, there is a delay of at least 3 seconds
before compressor starts.
Fig.7
Do not reuse drained oil or use any oil that has been exposed to atmosphere. Procedures for
adding or removing oil are given in Carrier Standard Service Techniques Manual, Chapter l.,
Refrigerants.
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 the system is not
leaking oil.

PRE-START-UP

START- UP

Oil Charge (see Tables l.) – Allow unit to run
for about 20 minutes. Stop unit and check
compressor oil level at sight glass. Add oil if
necessary to bring oil to the correct level show
in Fig 8. Use only Carrier-approved
compressor oil. Approved oils are:
Witco Chemical Corp ..................Suniso 3GS
Texaco, Inc ................................WF32
Petroleum specialties Co ..............Cryol 150
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