Hitachi FS3 Series, Service Manual

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TROUBLESHOOTING
Phenomenon Cause Check Item
Action
(Turn OFF main switch)
Check for clogging. Remove clogging.
Check connecting wiring
and connectors.
Replace connector.
Check operating sound
from coil.
Replace coil.
Check discharge gas
thermistor.
Replace thermistor.
Faulty or Malfunction of
Expansion Valve
Check attaching state of
discharge gas thermistor.
Reattach thermistor.
Faulty Gas Bypass Solenoid
Valve
Check for clogging.
Replace gas bypass
solenoid valve.
Overcharged Refrigerant
Check cycle operating
temp.
Charge refrigerant
correctly.
Mixture of Non-Condensable
Gas in Refrigeration Cycle
Check ambient temp. and
pressure.
Recharge refrigerant after
vacuum pumping.
Clogging of Discharge Piping Check for clogging. Remove clogging.
Liquid Line Stop Valve or Gas
Line Stop Valve are not in
Operation
Check stop valves. Fully open stop valves.
Activation of
High Pressure
Switch due to
Excessively
High Discharge
Pressure
Clogging of Check Valve Check for clogging. Replace check valve.