Mitsubishi Electric PURY-100TMU, Service Handbook

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Solenoid Valve (SV1~6)
Check if the control board’s output signals and the operation of the solenoid valves match.
Setting the self-diagnosis switch (SW1) as shown in the figure below causes the ON signal of each relay to be output to
the LED’s.
Each LED shows whether the relays for the following parts are ON or OFF. When a LED lights up, it indicates that the
relay is ON.
1 2 3 4 5 6 7 8
1) In the case of SV1 (Bypass Valve)
(a) When the compressor starts, SV1 is ON for 4 minutes, so check operation by whether the solenoid valve is
emitting an operating noise.
(b) Changes in the operating condition by solenoid valve operation can be confirmed by the temperature of the
bypass circuit and the sound of the refrigerant.
2) In the case of SV2 (Bypass)
(a) SV2 goes ON in accordance with the rise in the high pressure in the cooling mode and heating mode, so check
its operation by the LED display and the operating noise emitted by the solenoid valve.
(Conditions during operation: See Control of Outdoor Unit. )
(b) Changes in the operating condition by solenoid valve operation can be confirmed by the temperature of the
bypass circuit and the sound of the refrigerant.
3) SV3 ~ 6 (Control of heat exchanger capacity)
(a) Operations can be confirmed by LED display and operating sound of solenoid valve, because one or more of
SV3 ~5 are turned on depending on conditions during cooling-only operations.
(b) Operation can be confirmed by LED display and operating sound of solenoid valve, because all of SV3 ~ 5 are
turned on during heating-only operations.
(c) Operations can be confirmed by LED display and operating sound of solenoid valve, because one or more of
SV3 ~6 are turned on depending on conditions during cooling-principal and heating-principal operations.
SW1
LED
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON
SV6 SV5
SV4 SV3 SV2 SV1
* Connector connection specifications on the pressure sensor body side.
The connector’s pin numbers on the pressure sensor body side differ from the pin numbers on the main circuit board
side.
Vcc
Vout
GND
Sensor Body Side
Pin1
Pin2
Pin3
MAIN Board Side
Pin3
Pin2
Pin1