Sinclair SCV-50EA Service Manual page 80

P2: Low pressure protection
Low pressure protection
Whether wiring connection between low pressure switch and PCB is
connected well or properly.
Whether the low pressure switch is damaged.
Short-circuit low pressure switch and check whether the
system can work normally.
Whether the cooling system can work as normal.
Check whether the outdoor ambient temperature is too low.
Whether refrigerant system leaks.
Connect pressure gauge with the system measuring port.
Whether EXV works properly or stuck or blocked
Replace outdoor main PCB.
LED displays P2
YES
NO
NO
YES
NO
NO
NO
NO
NO
YES
Replace low pressure switch .
Stop the unit.
Leakage detecting: add nitrogen or refrigerant
YES
into the system. "si","si" will sound evidently if
leaks heavily. Use soap water(the combination
of water and detergent ) or electronic detector
to detect if leaks slightly.
YES Replace the EXV, then use high
pressure nitrogen to clean and air the
pipeline, add the refrigerant at last.
78
Connect well again.