Sinclair SCV-EB Series Service Manual page 74

5.27 Pd Troubleshooting
5.27.1 Digital display output
5.27.2 Description
 High temperature protection of air side heat exchanger refrigerant outlet in cooling mode. When the air side heat
exchanger refrigerant outlet temperature is higher than 61°C for more than 3 seconds, the system displays Pd
protection and heat pump stops running. When the air side heat exchanger refrigerant outlet temperature returns
drops below 55°C, Pd is removed and normal operation resumes.
 Heat pump stops running.
 Error code is displayed on the refrigerant system PCB digital tube and user interface..
5.27.3 Procedure
The fan or fan motor is blocked or damaged
Air side heat exchanger refrigerant outlet
temperature sensor(T3) is loose
Air side heat exchanger refrigerant outlet
temperature sensor has short-circuited or failed
The air side heat exchanger dirty or blockage
Poor ventilation at installation position
The location of heat pump is near the place
where temperature is too high
Replace refrigerant system PCB
Notes:
1. Air side heat exchanger temperature sensor (T3) connection is port CN6 on the refrigerant system PCB.
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor's resistance
characteristics table, the sensor has failed.
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Pd
No
1
No
No
No
No
No
Ensure the fan or fan motor works
Yes
Ensure the temperature sensor is
Yes
Yes
Replace the temperature sensor
2
Yes
Clean the air side heat exchanger
Install the heat pump in the place with
Yes
good ventilation.
Make sure heat pump is away from high
Yes
temperature heat source.
normally
connected properly