R410a Full DC Inverter Mini VRF MCAC-VTSM-2013-12
112 Troubleshooting
7.10 P2: Low pressure protection (for all models)
When the pressure is lower than 0.05MPa, the system will display P2 protection, the ODU in standby. When
the pressure is higher than 0.15MPa, P2 disappears and resumes normal operation.
LED
displays
P2
Low pressure protection
Whether wiring connection between low pressure switch and
PCB is connected well or properly.
Whether the low pressure switch is damaged.
Connect well
again.
Confirm: short-circuit low pressure switch and check
whether the system can work normally.
Check whether the cooling system can work as normal.
YES
NO
Check whether the outdoor ambient temperature is too low.
YES
Stop the unit.
NO
Whether refrigerant system leaks.
YES
Leakage detecting: add nitrogen or refrigerant
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.
Whether the refrigerant pipe is blocked.
YES
Remove the refrigerant pipe and then use high
pressure nitrogen or refrigerant to blow the pipe.
Vacuume the pipe then add the refrigerant again.
NO
Replace outdoor PCB.
NO
NO
YES
Replace low pressure.
switch.
Whether EXV works properly or stuck or blocked
YES
Replace the throttle parts.
Whether the reversion of the four-way valve is well
or mixed up with air or blocked.
Replace four-way valve.
YES
NO
NO
