Mitsubishi Heavy Industries SRK50HE-S1 Technical Manual page 35

Abnormality of outdoor unit
Does compressor operation?
YES
Is heat exchanger sensor volume for
inside unit good?
YES
Is refrigerant amount normal?
YES
Clogged capillary tube or strainer,
defective EEV, etc.
(g) Phenomenon observed after shortcircuit, wire breakage on sensor.
(i) Indoor unit
Operation
Sensor
mode
Cooling
Room temperature
sensor
Heating
Cooling
Heat exchanger
sensor
Heating
(ii) Outdoor unit
Operation
Sensor
mode
Cooling
Heat exchanger
sensor
Heating
Cooling
Outdoor air
temperature sensor
Heating
Discharge pipe
All modes
sensor
(h) Checking the indoor electrical equipment
(i) Indoor unit circuit board check procedure
1) Turn off the power.
2) Disconnect the wires connected between the indoor and outdoor units at the terminal block. (They can be disconnected at
either the indoor or outdoor unit's terminal block.)
3) Turn on the power.
4) The voltage between 1 and 2 on the terminal block should not be AC 220-240 V.
5) Press the unit's ON/OFF button for 5 seconds or longer (a beep which indicates receiving will be emitted). Then check
the following items.
1 The indoor unit's fan motor runs.
2 The run light lights up.
6) There should be voltage (AC 220-240 V) between terminals 1 and 2 on the terminal block.
With the analog tester set in the DC 30 V range, if the voltage at 2 (+) and 3 (-) is measured, the needle oscillates at
about 12V.
7) It is possible to run and stop the unit using the remote controller. (The hot keep function is activated.)
If operation is as described above, the indoor unit's board is normal.
Notes (1) Since the communication timing signal is transmitted only when the 52C is turned ON, check it under the operating condition.
Notes (2) Check the voltage on the terminal block.
● Power supply : Between 1-2 (AC 220-240V)
● Signal : Between 2-3 (Changing between DC 0-Approx. 12V)
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
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)
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
208
-
[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
Broken wire