5. IPM check method
Turn off the power, let the large capacity electrolytic capacitor (C10) discharge completely, and dismount the IPM. Then, using a tester, check leak
current between C and E.
When using a digital tester, the (+) and (-) tester lead wires in the table must be reversed.
Needle-type tester Normal resistance value
(-) (+)
∞
(several MΩ)
P
N
U
V
W
5.1. IPM internal circuit diagram
YES
Immediately
after startup
YES
YES
NO
NO
NO
YES
NO
Connect power cord
to AC outlet.
Normal
Using remote control,
operate air conditioner
so that compressor
starts.
Check 220-240 VAC
between (1) and (N)
on outdoor unit PWB.
Is LED1 on outdoor
unit flashing?
Compressor starts up.
Does LED1 indicate
DC overcurrent error?
Does LED1 indicate
rotation error?
Replace compressor.
Does LED1 remain lit?
Serial signal error.
Check inter-unit wiring.
Check indoor and
outdoor unit PWBs.
Replace outdoor unit
PWB.
Check compressor.
2/3-way valve closed.
Refrigerant shortage.
Replace outdoor unit PWB.
Check 320 VDC between
pins IPM (20) and (24)?
LED1 is flashing.
Replace outdoor unit PWB.
Replace expansion valve.
Disconnect (CN3) lead
wires of FAN motor.
Disconnect (CN12)
expansion valve.
Replace outdoor unit PWB.
YES
NO
YES
NO
NO
YES
YES
No
(unlit)
FUSE and+12 V, +15 V,
+18V on PWB
(LED1 is still off)
Replace outdoor unit PWB.
Replace FAN motor.
LED1 is flashing.
YES
NO
Needle-type tester Normal resistance value
(-) (+)
U N
∞
(several MΩ)
V
W
Values in ( ) are for digital tester.
12PHR-N_S530612PHRN.indd 10 2013/8/7 15:42:16
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