Sinclair SDV5 Series Service Manual page 62

System contains air or nitrogen
The condenser heat exchange is poor
The high pressure side is blocked, caused
by crushed or bent pipe or blocked EXV
Inverter module has short-circuited
Compressor has malfunctioned
Replace outdoor main PCB
Notes:
1. An indoor load that is too large causes suction and discharge temperatures to be higher than normal.
2. Excess refrigerant causes discharge temperature to be lower than normal, discharge pressure to be higher than normal and suction pressure to be higher
than normal.
3. Air or nitrogen in the system causes discharge temperature to be higher than normal, discharge pressure to be higher than normal, compressor current to
be higher than normal, abnormal compressor noise and an unsteady pressure meter reading.
4. In cooling mode check outdoor heat exchangers, fans and air outlets for dirt/blockages. In heating mode check indoor heat exchangers, fans and air outlets
for dirt/blockages.
5. High pressure side blockage causes discharge temperature to be higher than normal, discharge pressure to be higher than normal and suction pressure to
be lower than normal.
6. Set a multi-meter to buzzer mode and test any two terminals of P N U V W of the inverter module. If the buzzer sounds, the inverter module has
short-circuited.
7. The normal resistances of the inverter compressor are 0.5-1.5Ω among U V W and infinite between each of U V W and ground. If any of the resistances
differ from these specifications, the compressor has malfunctioned.
2.18 P4: Discharge temperature protection (For all models)
2.18.1 Digital display output
P4
2.18.2 Description
 Discharge temperature protection.
 The system stops running.
 Error code is displayed on the unit with the error.
2.18.3 Trigger / recover condition
 Trigger condition: Discharge temperature (T5) > 115
 Recover condition: Discharge temperature (T5) < 90
 Reset method: Resume automatically.
No
3
No
4
No
5
No
6
No
7
No
o
C.
o
C.
Flush all refrigerant then vacuum the
Yes
system and recharge refrigerant. Add oil
to the system if it leaks
Yes
Inspect the system and fix the error
Yes
Inspect the system and fix the error
Yes
Replace the inverter module
Yes
Replace the compressor
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