Mitsubishi SRK50ZHX-S Technical Manual page 47

Outdoor fan motor error
Is connector connection good?
YES
* Disconnect the fan motor
connector, then investigate
the DC fan motor and out-
door unit circuit board sepa-
rately.
Is the output of the outdoor unit's
printed circuit board normal?
YES
Normal
Rotor lock
(8) Phenomenon observed after shortcircuit, wire breakage on sensor
(a) Indoor unit
Operation
Sensor
mode
Cooling
Room temperature
sensor
Heating
Cooling
Heat exchanger
sensor
Heating
Cooling
Humidity Sensor
Heating
1 Humidity sensor operation
Failure mode
1 Disconnected wire
2 Disconnected wire
12 Disconnected wire
1 and 2 are short
circuited
Remark: Do not perform a continuity check of the humidity sensor with a tester. If DC current is applied, it
could damage the sensor.
NO
Correct connector connection
Is DC fan motor resistance value good?
NO
Defective outdoor PCB
Is output voltage applied to all 3
phases of power transistor?
YES
Inspect compressor.
Shortcircuit
Release of continuous compressor operation command
Continuous compressor operation command is not released.
System can be operated normally.
High pressure control mode (Inverter stop command)
1 in the table below.
Normal system operation is possible.
Control input circuit reading
Humidity reading is 0%
Humidity reading is 100%
NO
YES
Replace outdoor fan motor
NO
Defective outdoor PCB
¡ Check compressor wiring visually.
¡ Check insulation resistance. (1 MΩ or over)
¡ Check coil wire resistance. (Few Ω)
Phenomenon
Continuous compressor operation command is not released.
Release of continuous compressor operation command
Continuous compressor operation command is not released.
(Anti-frosting)
Hot keep (Indoor fan stop)
1 in the table below.
Air conditioning system operation
Anti-condensation control is not done.
Anti-condensation control keep doing.
44
- -
[Defective fan motor, connector
poor connection, defective PCB]
[Compressor defect, outdoor
unit circuit defect]
If check results are normal,
compressor is locked.
Disconnected wire
Humidity sensor
element
Connector
(CnF)
Humidity sensor assembly