Commpressor Low- Pressure Protection E3; Compressor Discharge Temp Protection E4 - Sinclair S therm Series Service Manual

3.2 Commpressor Low- pressure Protection E3

Comp Low-pressure Protection E3
Check if comp low-pressure switch
Check if the fans stop running or reverse

3.3 Compressor Discharge Temp Protection E4

Comp Discharge Temp Protection E4
Measure if the exhaust
temperature of compressor
reaches120℃
Check if the the electronic
expansion valve is blocked
Check if the system has leaked
Repair the leakage of system
pipe and add refrigerant
according to the required volume
is broken or the wiring is loose.
no
no
Check if the system has leaked
no
yes
yes
no
yes
yes
low- pressure or rewire
yes
no
Repair the leakage of system
pipe and add refrigerant
according to the required volume
Measure if the
resistance of temperature
sensor is correct
yes
Replace the mainboard
of AP2
Replace the electronic
expansion valve
The refrigerant of the system is
not enough and add refrigerant
according to the required volume
143
Replace comp
Check the fans
no
Replace the corresponding
exhaust temperature
sensor