Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 351

[ IX Troubleshooting ]
[5] Check whether the IPM screw
Check the in- terminal is not loose.
verter circuit
Check the exterior of the IPM.
trouble.
Check the resistances between
each terminal of IPM.
Refer to 9.[4].5.(5) for details on
IPM troubleshooting.
[6] Remove the wire for the outdoor
Check the fan fan motor, and check the fan
motor ground motor megger and the winding
fault or the resistance.
winding.
[7] (1) Check the fan output wiring. Connector contact failure
Check the FAN
INV board fail-
ure.
(2) Check the connector CN-
(3) Check the FAN INV board
(4) Check the transformer on
Items to be checked
VDC connection.
failure.
the FAN INV board.
- 342 -
Phenomena
1) Terminal screws are
loose.
2) IPM is cracked due to
swelling.
3) Check the resistances
between each terminal of
IPM.
4) All normal for items 1) - 3)
above.
1) Fan motor megger failure
Failure when the megger
is 1Mohm or less.
2) Fan motor disconnection
Standard:
The winding resistance is
approximately several
ohm.It varies depending
on the temperature, or
while the inner thermo is
operating, it will be
ohm
Board side (CNINV)
Fan motor side
Connector contact failure
1) The voltage imbalance
among each motor wiring
during operation
The voltage imbalance is
greater than the larger of
the values represented
by 5% or 5 V.
2) The same error occurs
even after the operation
is restarted.
The same error occurs even if
the board is replaced as de-
scribed in (3)
Remedy
Check for loose IPM terminal
screws and tighten them.
Replace the IPM. Check the oper-
ation in [3] or [4] after replacing the
IPM.
In the case of an output voltage im-
balance or error reoccurrence: Re-
place the G/A board.
In the case of an output voltage
imbalance or error reoccur-
rence after replacement:
Replace the INV board.
Replace the IPM.Check the opera-
tion in [3] or [4] after replacing the
IPM.
In the case of an output voltage im-
balance or error reoccurrence: Re-
place the G/A board.In the case of
an output voltage imbalance or er-
ror reoccurrence after replace-
ment:
Replace the INV board.
Replace the IPM.
In the case of an output voltage im-
balance or error reoccurrence:
Replace the G/A board.In the case
of an output voltage imbalance or
error reoccurrence after replace-
ment:
Replace the INV board.
Replace the fan motor.
Connect the connector.
Connect the connector.
Replace the FAN INV board.
Replace the power-supply trans-
former on the FAN INV board.