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* 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.
Sensor Body Side
MAIN Board Side
Vcc
Pin 1
Pin 3
Vout
Pin 2
Pin 2
GND
Pin 3
Pin 1
Solenoid Valve (SV1, SV2) (PU(H)Y-200, 250YMF-C)
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.
(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.
SW1
SV2
SV1
LED
1 2 3 4 5 6 7 8 9 10
ON
PU(H)Y-P200, 250YMF-C
LED
1 2 3 4 5 6 7 8 9 10
ON
SV4
SV3
1 2 3 4 5 6 7 8
SV2
SV1
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.
(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, 4 (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, 4 are turned on depending on conditions during cooling-only operations.
