R410A Full DC Inverter Split Duct Type Technical Manual MCAC-UTSM-201503
45
P1: High temperature protection or high temperature protection of discharge sensor
P2: Low pressure protection
P1: High pressure
protection
The heat exchange of condenser is
not good. It may be caused by dirty
heat changer, abnormal ODU fan
running, ODU are too near to each
other, etc.
Check the system and
fixed up the error
The high pressure side of the system
is blocked
for squashed pipe,
blocked valve or closed stop valve
Make sure all valves are
open, check the system, and
remove the obstacle
Refrigerant is excess
Discharge part of the refrigerant. Add
some oil if it leaks during the discharge
System contains air or nitrogen
Discharge the entire refrigerant. Then
vacuum the system and refill the
refrigerant. Add oil to the system if it leaks.
Yes
No
No
No
No
Yes
Yes
Yes
P2/H5: Low pressure protection
System is lack of refrigerant.
(Refrigerant recharging is not
according to the requirement,
or there has refrigerant
leakage)
Add refrigerant or check up
the leakage of the system
The low pressure side is blocked for
squashed pipe, closed EXV, closed
strop valve, dirty filter, etc.
Make sure all valves are open, clean
the filter, if the filter is blocked by ice,
the system should be clean
Yes
Yes
The heat exchange of evaporator
is not good. It may be caused by
dirty heat changer, abnormal IDU
fan running, some barrier in front
of the air outlet, etc.
Check the system and
fixed up the error
Yes
No
No
No
Outdoor main control
board is damaged
Replace the outdoor
main control board
Outdoor main control
board is damaged
Replace the outdoor
main control board
