Hitachi Utopia PAS-3HVRG, Service Manual

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1-20
TROUBLESHOOTING
Cause Check Item
Action
(Turn OFF Main Switch)
Phenomenon
Activation of
High Pressure
Switch due to
Excessively
High Discharge
Pressure
Faulty
Magnet Switch
Measure discharge
pressure.
Check continuity after
decreasing of pressure.
Replace it if faulty.
Faulty
Pressure
Switch
Faulty High
Pressure
Switch
Measure resistance
by tester. Repair looseness.
Replace connector.
Repair connections.
Replace Magnet Switch.
Insufficient
Contacting
Check connections. Repair connections.
Replace it if faulty.
Incorrect
Connection
Calculate heat load.
Reduce heat load or
use a bigger unit.
Check for hot air near
the ceiling (Heating).
Make good circulation.
Check for short
circuited air (Heating). Remove
short-circuited air.
Check for other
heat source.
Remove heat source.
Excessively High Temp.
Air to Indoor Unit
Heat Exchanger
Check wiring.
Check connections.
Incorrect Connection
Malfunction A Contact
Clogging of Heat
Exchanger?
Remove clogging.
Check for dust on
air filter.
Remove dust.
Check for any obstacles
at inlet or outlet of
heat exchanger.
Remove obstacles.
Check the service
space.
Secure service space.
Check for speed.
Outdoor Fan: Cooling
Indoor Fan:
Heating
Replace fan motor
if faulty.
Insufficient Air Flow to
Heat Exchanger
(Outdoor Heat Exchanger
during Cooling Operation
or Indoor Heat Exchanger
during Heating Operation)
Measure continuity after
fan motor temperature
decreases to room temp.
Replace it if faulty.
Faulty
Thermostat
Faulty of
Internal
Thermostat
Measure resistance
by tester. Correct looseness.
Replace connectors. Insufficient
Contacting
Check connections. Repair connections.
Incorrect
Connection
Activation
of Internal
Thermostat
of Outdoor
Fan Motor
Measure resistance
between wires and
Insulation resistance.
Faulty of Outdoor Fan Motor