R410A All DC Inverter V5 X Series 50Hz MCAC-VTSM-2015-10
146 Troubleshooting
4.14 H8: Malfunction of pressure sensor for discharge pipe
When the discharge pressure is lower than 0.3MPa, the system will display error H8, the ODUs will be on
standby. When the discharge pressure is back to normal, H8 is removed and normal operation resumes.
Note:
* How to check for high pressure sensor
Measure the resistance among the three terminals of the pressure sensor, if the resistance value is megohm or infinite, the
pressure sensor is disabled.
* The phenomenon of insufficient 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.
* The phenomenon of low pressure side blockage
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.
*For normal system running parameters please refer to attached table 3.
Outdoor main PCB is damaged
Replace the outdoor main
PCB
High pressure sensor is short circuited or disabled*
Insufficient refrigerant caused by insufficient recharge or
refrigerant leakage*
Add refrigerant or inspect
system for leaks
The low pressure side is blocked, caused by crushed or
bent pipe, closed EXV, closed stop valve, dirty filter, etc.*
open, clean the filter, if the
filter is blocked by ice, the
The heat exchange of evaporator is not good. It may be
caused by dirty heat exchanger, abnormal IDU fan
running, some barrier in front of the air outlet, etc.
Inspect the system and fix
the error
H8: Malfunction of pressure sensor for discharge pipe
High pressure sensor connection port on main control
board is loose
Fasten the connection port
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