Hitachi YUTAKI Series - Page 174

Troubleshooting
Service Manual
172
Initial troubleshooting
SMGB0066 rev.0 - 12/2009
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Insufcientheating
process
Heating load is higher than heating capacity Check the heating load Install an adequate size unit
Excessively low suction
pressure
Gas leakage
Check gas leakage &
super-heat
Charge correctly the
quantity of refrigerant
Clogging of the expansion valve
Check the clogging of
expansion valve
Remove clogging
Clogging of the strainer
Check temperature
difference before/after
strainer
Clean or replace the
strainer
Clogging of side low pressure pipe
Check the temperature
difference of each pipe
Remove the clogging
Malfunction of the check valve
Check the difference
temperature before/after
check valve
Replace the check valve
Shortageairowintheairsideheatexchanger
Excessively dust in airside
heat exchanger
Remove it
Clogging of the inlet/
outlet at the air side heat
exchanger is clock
Shortage the service
space for Yutake unit
Secure service space
Device rotation fan motor
Correct wiring of the fan
motor
Airtemperaturethroughheatexchangerairow Check the air short circuit Repair short circuit
Defrosting it is not enough
Check the evaporating
thermistor
Replace the thermistor
Check the 4-way valve Replay 4-way valve
Excessively high
discharge pressure
Shortageofwaterow
Check the difference of
temperature between
inelet/outlet of the unit
Increasethewaterow
Pump reverse rotation
Check the rotation
direction
Correct the direction
Air mixing in the water Check air purger Empty the air contained
Excessively high hot
water temperature
Check the water
thermistor of the unit
Replace the water
thermistor or PCB
Refrigerant excessively
discharged
Check refrigerant cycle
temperature
Charge the correct quantity