Hitachi FS3 Series, Service Manual

Page: 24 / 240

1
16
TROUBLESHOOTING
1.1.7 ABNORMALITIES OF DEVICES (Cont.)
Phenomenon Cause Check Item
Action
(Turn OFF main switch)
Check for filter clogging. Remove clogging.
Check for any obstacles at
inlet or outlet of indoor
unit.
Remove Obstacles.
Insufficient
Air Flow to
Indoor Unit
Heat
Exchanger
Check indoor fan speed. Replace fan motor.
Excessively
High Air
Temp. to
Indoor Unit
Heat
Exchanger
Check whether or not
short-circuited air exists.
Remove cause of short
circuited air.
Excessively
Charged
Refrigerant
Check refrigerant quantity
*1).
Correctly charge
refrigerant
Non-
Condensate
Gas in Ref.
Cycle
Check refrigerant quantity
*1).
Recharge refrigerant after
vacuum pumping
Excessively
High
Discharge
Pressure
Clogging of
Discharge
Pr. Piping
Check for clogging Remove clogging
Malfunction or Internal
Leakage of 4-Way Valve
Check temp. difference at
inlet and outlet of 4-way
valve.
Replace 4-way valve.
Malfunction of Check Valve of
Outdoor Unit
Check temp. difference at
inlet and outlet of check
valve.
Replace check valve.
Failure of
Bypass
Solenoid
Valve
Chek for leakage of
selenoid valve
Replace solenoid valve.
Excessively
High Suction
Pressure Malfunction
or Internal
Leakage of
4-Way Valve
Check temp. difference at
inlet and outlet of 4-way
valve.
Replace 4-way valve
Insufficient
Heating
Operation
Discharge Temp. of Indoor
Unit Is Unstable.
Check for expansion valve
of indoor unit in the same
system.
Replace failed expansion
valve of indoor unit.
*1): Refer to Item 16.6 of TC