Mitsubishi Electric MCFH-13NV-E3 Service Manual page 32

How to check mis-wiring and serial signal error (when outdoor unit does not work)
E
Yes
Repair wiring.
Is there 20V DC between both ends of R132 when
52C contactor turns ON?
(By tester, the stylus is between 0 ~ 20V.)
Yes
1. Turn OFF the power supply.
2. Reconnect in-out connecting wire.
3. Turn ON the power supply.
3 minutes later, when the EMERGENCY OPERATION switch is
pressed and 52C contactor turns ON, is there 220-240V AC between
the outdoor terminal block 2 and N ?
Yes
Is there 5V DC between J9 -J8
+
board? 2
Yes
Is there 10V DC between both ends of R601?
(By tester, the stylus is between 5 ~10V)
Yes
Replace the outdoor DEICER P.C. board.
1. Turn OFF the power supply.
2. Turn ON the power supply.
3. Press the EMERGENCY OPERATION switch.
3 min. later, when 52C contactor turns ON, what self-check result
is displayed on OPERATION INDICATOR lamp indoor unit?
Is there mis-wiring, poor contact, or wire disconnection?
1. Turn OFF the power supply and disconnect in-out connecting wire on the indoor side.
2. Short-circuit between indoor terminal block
3. Turn ON the power supply and press the EMERGENCY OPERATION switch.
No
2
on the outdoor DEICER P.C.
–
2
Start
Mis-wiring is indicated.(1-sec.ON,1-sec.OFF)
No
and .
N 3
No
No
No
32
1 Short circuit of JPG and JPS on the
indoor electronic control P.C. board
enables self-check to be displayed in 3
seconds.
Serial signal error is indicated.
(1-sec.ON, 2.5-sec.OFF)
1
Replace the indoor electronic control
P.C. board.
Rectify in-out connecting wire.
Check and rectify the fuse and varistor on
the outdoor DEICER P.C. board.
Rectify in-out connecting wire.
2 While the serial signal error is indicated,
52C contactor alternates ON for about 10
seconds and OFF for 3 minutes.
Measure the voltage when 52C contactor
is ON.