Mitsubishi Electric PUZ-A12NKA7 Service Manual page 53

10-6-1. Check method of outdoor controller circuit board
PUZ-A12NKA7
PUZ-A12NKA7-BS
PNC board check
Is the voltage of main incoming
power 198–253 V AC?
Is the voltage of bus var voltage
(between DS1 "+" and "−")
280–350 V DC?
Did the fuse (F1 and F2) blow?
Did the fuse (F3 and F4) blow?
Is the voltage of the compressor
(U-V,U-W and V-W) balanced?
Normal
TB1
L2
L1
208/230 V AC
±10%
OCH636A
PUZ-A18NKA7
PUZ-A18NKA7-BS
Turn off the incoming power supply and
check the resistance of PTC1and PTC2 on
the PNC board.
PTC1 or PTC2 = open ?
Replace the PNC board.
Outdoor controller circuit board
PTC1, PTC2
PUY-A12NKA7
PUY-A12NKA7-BS
Check the breaker and power supply.
• Check wiring.
• Replace the PNC board.
Check the indoor controller board wiring.
Check the wiring for 21S4.
• Check wiring.
• Check model setting switch.
ACL
U V W
U–V 10–200 V AC
V–W 10–200 V AC
W–U 10–200 V AC
Comp
53
PUY-A18NKA7
PUY-A18NKA7-BS
PUZ only