MIV V5 Heat Recovery DC Inverter R410A
DM14-01.01.18en
Troubleshooting
170
4.11 H8: High pressure sensor error
When the discharge pressure is lower than 0.3MPa, the system will display H8 error, the ODU in standby.
When the discharge pressure is back to normal, H8 disappears and normal operation resumes.
Note:
1. How to check whether the high pressure sensor is short circuit or disabled
①
Measure the resistance among the three terminals of the pressure sensor, if the resistance value is megohm or infinite, the
pressure sensor is disabled, otherwise, it may be normal.
2. The phenomenon of lack of refrigerant
②
:
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.
3. The phenomenon of the low pressure side is blocked
③
:
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.
High pressure sensor is
short circuit or disabled
①
Replace the sensor
System is lack of refrigerant
②
.
(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
③
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
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
No
No
No
No
No
H8: High pressure sensor error
High pressure sensor connection
port on main control board is loose
Fasten the connection port
Yes
Yes
Yes
Yes
Outdoor main PCB
is damaged
Replace the outdoor
main PCB
