TESTING - TM-5-4120-374-130124

TM 5-4120-374-13

5-8. COMPRESSOR (CONT)

LOCATION/TESTING

ACTION

REMARKS

TOP OF HOUSING

6. Compressor

a. Connect suction and discharge pressure gauges to the suction

and discharge service valves.

b. Open suction and discharge service valves.

c. Operate the air conditioner in the cooling mode and verify

that the normal operating pressures are as follows:

Normal Operating Pressures

Outdoor Ambient Temperature

95F(35C)

120F/125F(48.9C/57.7C)

90F/80F(32.2C/26.7C)DB/WB

return air to unit

6171 PSI

Suction Pressure

230260 PSI

Discharge Pressure

At 80F/67F(26.7C/19.4C)DB/WB return air to unit

4454 PSl

Suction Pressure

150175 PSl

Discharge Pressure

d. Stop air conditioner.

e. Close suction and discharge service valves.

f. Remove gauges.

Disconnect input power source before performing this maintenance task.

g. Operate the air conditioner in the cooling mode and using a

multimeter, measure the insulation resistance of the compressor

internal motor windings at the start relay and selector switch.

h. Verify that the insulation resistance between the windings

and compressor frame is NOT less than 60 megohms.

i . Verify that the insulation resistance of the main winding

(terminal pin A to C) is between .6 and .8 ohms.

j. Verify that the insulation resistance of the auxiliary winding

(terminal pin A to B) is between 5 and 7 ohms.

k. If testing indicates that the compressor is defective, remove

or repair compressor.

5-12