Mitsubishi Electric MSZ-A09RV Service Manual page 51

J
Check of R.V. coil
Heating operation works when cooling is expected.
• If the connector CN 913 is connected or the R.V. coil is open, the voltage occurs
between the terminals even when the control is OFF.
Disconnect connector between
compressor and IPM.
Turn on power supply to indoor
unit, and press emergency
operation switch to heating
operation.
Cooling operation works when heating is expected.
•First, measure resistance of the R.V. coil to check if it is defective or not.
• If the connector CN 913 is connected or the R.V. coil is open, the voltage occurs
between the terminals even when the control is OFF.
Disconnect connector between
compressor and IPM.
Turn on power to indoor unit, and
press emergency operation switch
to cooling opeation.
K
Check of outdoor fan motor
Outdoor fan motor does not work.
Disconnect connector
CN 771 on relay P.C.
board.
Disconnect connector
between compressor
and IPM.
Turn on power supply
to indoor unit, and
press emergency
operation switch.
Outdoor terminal block TB1
N
Indoor-outdoor
2
connecting
wire
3
3 min. after power turns on, is there voltage of 220-240V
AC between CN 913 1 and 2 on relay P.C. board ?
Is there voltage of 0V between CN 912 1 (+)and 2 (-)
on relay P.C. board?
Replace the relay P.C. board.
3 min. after power turns on, is there voltage of 220-
240V AC between CN 913 1 and 2 on relay P.C.
Is there voltage of 1V DC between CN 912 1 (+)and 2
(-) on relay P.C. board?
Replace the relay P.C. board.
3 minutes after power
turns on, is there voltage
of 220-240V AC between
outdoor terminal block 2
and N?
3 minites after
power turns on,
Yes
measure voltage
between terminals
of CN 771.
Yes
Yes
Outdoor terminal block TB1
Indoor -outdoor
connecting
wire
No
Yes
Relay P.C. board
· Press emergency operation
switch again to check if 52C
relay works.
No
· Re-connect connecting wire
of indoor and outdoor unit.
· Replace the indoor electronic
control P.C. board.
Is there voltage of
approx. 220-240V AC
either between 2 and 3
or between 2 and 4 or
between 2 and 5 at
CN 771?
51
Replace the R.V.
No
coil.
Approx. 1V
DC voltage
Replace the
occurs.
outdoor electrinic
control P.C. board.
4-way valve
AC 220-240V
N
1
2
3
CN913
Relay P.C. board
· Replace the lead
wires of R.V. coil.
· Re-connect
Yes
connector.
· Replace the 4-way
valve.
Replace the
No
outdoor electrinic
The voltage control P.C. board.
is 0V
Fan
motor
1 2 3
4 5 6
CN771
Replace the
relay P.C.
board.
· Replace the lead
No
wires of outdoor fan
motor.
· Re-connect
connector CN 771
· Replace the outdoor
Yes
fan motor.
2