IVT 12PHR-N Service Manual page 34

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