Replacement of Main Units
TD831077
VII-2
7
1. Compressors
Compressor trouble can generally be grouped under the following categories:
1 Mechanical trouble
→
(A) Compressor lock-up
(B) Trouble in boosting pressure
(C) Abnormal noises
2 Electrical trouble
→
(A) Winding burn-out
(B) Broken or disconnected wires
(C) Defective insulation
(D) Ground faults
Troubleshooting consists in pinpointing the trouble from the winding resistance (which differs depending on the
compressor concerned), insulation resistance, current, leakage circuit breaker tripping, extent to which the oil and
refrigerant have become contaminated, abnormal smells, pressure, noise and other factors on the basis of the H01
and H02 (PC comp), H11 and H12 (AC comp), H21 and H22 (SC comp) remote control displays.
Remarks: Insulation resistance (measure the insulation resistance of the live parts and non-live parts using a DC
500V megger)
(a) Fan motor
→
300 Ω or more
(b) compressor
→
100 Ω or more (item supplied for servicing)
(c) unit
→
10 Ω or more (this is measured because the unit contains refrigerant which reduces the
insulation resistance)
1-1. Judging whether a compressor needs to be replaced
1867_M_I
Start
Is the motor in the failed
compressor burnt out?
No
Drain off the oil inside the compressor.
Yes
Drain off the oil inside all
the compressors in the
same system.
Ye s
ASTM No. 4 or above
(Oil color)?
Pungent smell?
No
ASTM No. 4 or above
(Oil color)?
Pungent smell?
Yes
No
Two or more units incorporating
compressors with ASTM No. 4
or above(Oil color)?
Ye s
No
Is the unit that incorporates a
compressor with ASTM No. 4
or above(Oil color) the PC unit?
Yes
No
Two or more with ASTM No. 4
or above in the PC unit?
Ye s
Replace only
failed compressor.
Replace (all 3)
compressors
in PC unit.
Replace all
compressors in
same system.
Replace only
failed compressor.
Ref. to item 1-2. Ref. to item 1-5. Ref. to item 1-6. Ref. to item 1-2.
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