Mitsubishi Heavy Industries FDCW100VNX, Technical Manual

Page: 119 / 173

Service
- 118 -
E36 - Permanent Hotgas
YES
NO
YES
NO
YES
NO
NO
NO
NO
NO
YES
NO NO
YES
YES
YES
YES
YES
NO
Are the characteristics of the
hot gas sensor (Tho-D) OK?
Does the fault also occur during
cooling?
Does the discharge pipe temperature
protection control work properly?
Does the temperature (external
gauge) correspond with the
displayed temperature in the event
of an alarm?
- Is the filter blocked?
- Is the air circulation obstructed?
- Is the installation space sufficient?
- Is the heat exchanger dirty?
Replace defective sensor.
Insufficient amount of refrigerant.
Recharge it.
Check the operation data with
logging tool.
Defective control PCB - replace.
Is the service valve on the water
line open?
Open it.
Is the valve(s) (QM31or QN11)
functioning properly?
Is the operation signal of the
valves outputted correctly?
Replace the indoor unit relay board AA6.
Replace the valve(s).
If the phenomenon persists,
If the phenomenon persists,
Is there clogging on the strainer on
the water line?
YES
NO
Clean - up the strainer.
Is air - bleed done properly? Bleed the air in the water line.
Is the circulation pump setting
(2.2.5) done properly?
Set the appropriate value to
obtain enough water flow.
Is the operation signal of the pump
outputted correctly?
YES
Replace the pump.
Replace the indoor unit relay board AA6.
Troubleshooting guide