Mitsubishi Electric Mr. Slim SUZ-SA71VA Technical & Service Manual page 25

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.
In case CN602 (SA71) 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 CN602 (SA71) is connected.
Unit operates 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 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 ter-
minal of outdoor fan motor normal?
(Refer to 11-4.)
No
(Fixed to either 5 or 0 VDC)
Replace the outdoor fan motor.
OCH561
Is there 230 VAC between CN602 (SA71)
and on 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 CN602 (SA71)
and on 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
No
VDC repeatedly?
Does the outdoor fan motor rotate smoothly?
No
25
Replace the inverter
No
P.C. board.
Replace the inverter
Yes P.C. board.
Yes
Yes
Replace the inverter P.C. board.