Carrier X-POWER Series Service Manual page 158

R410A DC Inverter Series
4.12 P2/H5: Low pressure protection (Display on faulty unit, all the ODU in standby)
When the pressure is lower than 0.05MPa, the system will display P2 protection, all the ODU in standby.
When the pressure is higher than 0.15MPa, P2 disappear and resumes normal operation.
H5 error will display when system appear 3 times P2 protection in 30 minutes, it cannot resume
automatically, and it can resume only by restarting the machine.
P2/H5: Low pressure protection
System is lack of refrigerant
(Refrigerant recharging is not
according to the requirement,
or there has refrigerant
leakage)
No
The low pressure side is blocked
for squashed pipe, closed EXV,
closed strop valve, dirty filter, etc.
No
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.
No
Outdoor main control board is
damaged
Note:
1. The phenomenon of lack of refrigerant
Top temperature and discharge temperature of all compressors are higher than normal value, discharge pressure and suction
pressure are both lower than normal value, current is lower than normal value, suction pipe may be frosting. All the
phenomenon will disappear after recharging refrigerant.
2. The phenomenon of the low pressure side is blocked
The discharge temperature is higher than normal value*, low pressure is lower than normal value*, current is lower than
normal value* and suction pipe may be frosting.
*The normal system running parameters please refer to attached table 3.
*If the system install three-phase protector, and the three-phase protector connect with high pressure switch in series
connection, the system will display P1 protection when fist power on, and P1 protection will disappear after system is steady.
*If the system install three-phase protector, and the three-phase protector connect with low pressure switch in series
connection, the system will display P2 protection when fist power on, and P2 protection will disappear after system is steady.
176
①
.
Yes
Add refrigerant or check up
the leakage of the system
②
Make sure all valves are open, clean
Yes
the filter, if the filter is blocked by ice,
the system should be clean
Yes
Check the system and
fixed up the error
Replace the outdoor main control board
①
:
②
:
Carrier service manual
Troubleshooting