Mitsubishi MT300 User Manual

Service
-
159
-
'10 • HM-T-149
31 - S. fault HP
NO
NO
Is the saturated temperature of
balanced pressure same or similar
to the outdoor air temperature
when the outdoor unit is stopping.
YES
YES
Is the service valve on the refrigerant
line open?
Is the service valve on the water
line open?
Is the valve(s) (QM31 or QN11)
functioning properly?
Is the operation signal of the
valves outputted correctly?
Is there clogging on the strainer
on the water line?
NO
Is the circulation pump setting (2.2.5)
done properly?
Set the appropriate value
to obtain enough water flow.
If the phenomenon persists,
Is the operation signal of the pump
outputted correctly?
Replace the refrigerant.
Connect it correctly
Replace the pump.
Open it.
Clean-up the strainer.
Is air-bleed done properly?
Open it.
Bleed the air in the water line.
Is the pressure sensor (BP4)
correctly connected?
YES
Does the pressure (external meter)
correspond with the value
displayed in the indoor unit?
NO
Replace the pressure sensor.
YES
YES
YES
YES
YES
NO
NO
NO
Replace the indoor unit relay board AA6.
NO
Replace the valve(s).
Replace the indoor unit relay board AA6.
NO
YES
YES
YES
NO
NO
Troubleshooting guide

Mitsubishi MT300 Specifications

General

Brand	Mitsubishi
Model	MT300
Category	Heat Pump
Language	English