Mitsubishi Electric PUHY-P200 Service Handbook page 265

[8-6 Troubleshooting Solenoid Valve Problems ]
(3) In case of SV1a (Bypass valve)
This solenoid valve opens when powered (Relay ON).
1) At compressor start-up, the SV1a turns on for 4 minutes, and the operation can be checked by the self-diagnosis LED display
and the closing sound.
2) To check whether the valve is open or closed, check the change of the SV1a downstream piping temperature while the valve
is being powered.Even when the valve is closed, high-temperature refrigerant flows inside the capillary next to the valve.
(Therefore, temperature of the downstream piping will not be low with the valve closed.)
(4) In the case of SV5b (2-way valve) , SV5c (2-way valve) (only for P450 and P500 models)
This solenoid valve is a switching valve that closes when energized. Proper operation of this valve can be checked on the
LED and by the switching sound. During the cooling mode, SV5b and 21S4b, SV5c and 21S4c, are switched simultaneously,
which may make it difficult to check for proper operation of the SV5b or SV5c by listening for the switching sound. If this is the
case, the temperature before and after SV5b or SV5c can be used to determine if the refrigerant is the pipe.
(5) In the case of SV9 (Solenoid valve)
This solenoid valve is a switching valve that opens when energized. Proper operation of this valve can be checked on the LED
display and by the switching sound.
(6) In the case of SV10 (Solenoid valve)
This solenoid valve is a switching valve that opens when energized. Proper operation of this valve can be checked on the LED
display and by the switching sound.
(7) In the case of SV11 (Solenoid valve)
This solenoid valve is a switching valve that opens when energized. Proper operation of this valve can be checked on the LED
display and by the switching sound.
Do not give an impact from outside, as the outer hull will be deformed leading to the malfunction of the inner valve.
HWE14040
- 256 -
GB