Mitsubishi SRK52HE Technical Manual page 49

Abnormality of outdoor unit
Does compressor operation?
YES
Is heat exchanger sensor resistance
value good?
YES
Is refrigerant amount normal?
YES
Clogged capillary tube or strainer,
defective EEV, etc.
(7) 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.
(b) Outdoor unit
Operation
Sensor
mode
Cooling
Heat exchanger
sensor
Heating
Cooling
Outdoor air
temperature sensor
Heating
Discharge pipe
All modes
sensor
NO
Is capacitor for compressor normal?
Is connector for compressor connection
good?
Replace compressor.
NO
Replace heat exchanger sensor
NO
Does trouble persist after charging gas?
Insufficient gas
Shortcircuit
Release of continuous compressor operation command
Continuous compressor operation command is not released.
Compressor stop.
(Abnormality of outdoor unit)
High pressure control mode
1 in the table below.
Normal system operation is possible.
Control input circuit reading
Humidity reading is 0%
Humidity reading is 0%
Humidity reading is 0%
Humidity reading is 100%
Shortcircuit
System can be operated normally.
Defrosting is not performed.
System can be operated normally.
Defrosting is not operated.
Compressor overload protection is disabled.
(Can be operated.)
-
YES
YES
YES
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
Operates in the Dry region
Operates in the Dry region
Operates in the Dry region
Operates in the Cooling region.
Phenomenon
System can be operated normally.
Defrosting is performed for 10 minutes at approx. 35 minutes.
System can be operated normally.
Defrosting is performed for 10 minutes at approx. 35 minutes.
Compressor stop
47
-
[Compressor malfunction of
insufficient gas (refrigerant)]
NO
Replace capacitor for compressor.
NO
Correct connection
NO
Check if there are any places where
gas is leaking
Broken wire
Humidity sensor
element
Connector
(CnF)
Humidity sensor assembly
Broken wire