Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook page 146

5) Treatment of Fan Motor Related Troubles
Condition
1
The fan motor will not run
for 20 minutes or longer
when the AK value is
10%. (When the MAIN
board's SW1 is set as
shown below, the AK
value is displayed by the
service LED.)
SW1 = 1110001000
2
The fan motor's vibration
is great.
Possible Cause
1) The power supply voltage
is abnormal.
2) Wiring is faulty.
3) The motor is faulty.
4) A fuse (F1, F2, F3) is
defective.
5) The transformer (T01) is
defective.
6) The circuit board is faulty.
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Check Method and Treatment
If there is an open phase condition before the breaker, after
the breaker or at the power supply terminal blocks TB1A or
TB1B. Correct the connections.
If the power supply voltage deviates from the specified
range. Connect the specified power supply.
For the following wiring, 1 check the connections, 2 check
the contact at the connectors, 3 check the tightening torque
at parts where screws are tightened, 4 check the wiring
polarity, 5 check for a broken wire and 6 check for ground-
ing.
TB1A~NF~TB1B~CNTR1~T01~CNTR,
TB1B~CNPOW, CNFAN~CN04~CNMF,
CNFAN~52F~CN05~CNMF
CNFC1~CNFC2
* Check if the wiring polarity is as shown on the wiring
diagram plate.
Measure the resistance of the motor's coils: 20~60
Measure the motor's insulation resistance with a megger:
10 M (DC 500 V) or more
If a fuse is defective, replace it.
Judge that T01 is faulty. Go to "Individual Parts Failure
Judgment Methods."
If none of the items in 1) to 5) is applicable, and the trouble
reappears even after the power is switched on again,
replace the circuit board using the following procedure.
(When replacing the circuit board, be sure to connect the
connectors and ground wire, etc. securely.)
1
Replace the FANCON board only. If the problem is
solved, the FANCON board was defective.
2
Replace the FANCON board and replace the MAIN
board. If the problem is solved, the MAIN board is
defective.
3
If the trouble continues even after 1 and 2 above, then
both boards are defective.