Mitsubishi Electric Mr.SLIM SUZ-M25VA-ER Technical & Service Manual page 32

G Check of R.V. coil
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to "11-4. TROUBLE CRITERION OF
MAIN PARTS".
In case CN721(M25/35/50)/CN602(M60/71) is not connected or R.V. coil is open, voltage is generated between the
terminal pins of the connector although any signal is not being transmitted to R.V. coil.
Check if CN721(M25/35/50)/CN602(M60/71) is connected.
Unit operates in COOL mode even if it is set to HEAT mode.
Disconnect connector between
the compressor and the intelligent
power module.
Turn ON the power supply and start
heating test run.
(TEST RUN OPERATION: Refer to
11-5 )
Unit operates in HEAT mode even if it is set to COOL mode.
Disconnect connector between
the compressor and the intelligent
power module.
Turn ON the power supply and start
cooling test run.
(TEST RUN OPERATION: Refer to
11-5 )
H Check of outdoor fan motor
Disconnect the connectors CN931
and CN932 from the inverter P.C.
board. Check the connection between
the connector CN931 and CN932.
Is the resistance between each termi-
nal of outdoor fan motor normal? (Re-
fer to "11-4. TROUBLE CRITERION
OF MAIN PARTS". )
No
(Fixed to either 5 or 0 V DC)
Replace the outdoor fan motor.
OCH684G
Is there 230 VAC between CN721
(M25/35/50)/CN602(M60/71)
the inverter P.C. board 3 minutes after the
power supply is turned ON?
Yes
Replace the 4-way valve.
Is there 230 VAC between CN721
(M25/35/50)/CN602(M60/71)
the inverter P.C. board 3 minutes after the
power supply is turned ON?
No
Replace the 4-way valve.
Yes
Disconnect CN932 from the inverter P.C. board, and turn on the power sup-
ply.
Rotate the outdoor fan motor manually and measure the voltage of CN931.
Between 1(+) and 5(−)
Between 2(+) and 5(−)
Between 3(+) and 5(−)
Does the voltage between each terminal become 5 and 0 V
No
DC repeatedly?
Does the outdoor fan motor rotate smoothly?
No
32
Replace the inverter
and on
No
P.C. board.
and on Replace the inverter
Yes
P.C. board.
Yes
Yes
Replace the inverter P.C. board.