Hitachi RAS-2-HVNP Service Manual page 210

8. Troubleshooting
Phenomenon
Insufficient Air Flow to the Heat Exchanger (Outdoor Heat
Exchanger during the Cooling Process or Indoor Heat
Activation of the high-pres-
sure switch due to the
excessively high discharge
pressure
Faulty High-Pressure
Mixture of the non-condensate gas in the refrigerant cycle
Liquid line stop valve or gas line stop valve is not in
Faulty Magnet Switch
196
SMGB0079 rev.0 - 01/2013
Cause
Exchanger during the Heating Process)
Excessively High Temp. Air to the Indoor Unit
Faulty Pressure Switch
Switch
Insufficient Contacting
Incorrect Connection
Overcharged refrigerant
Clogging of the discharge piping
operation
Incorrect Connection
Malfunction A Contact
Check item
Check the heat exchanger Remove the dust or the
for dust or for clogging
Check the air filter for dust
Check for any obstacles at
the inlet or the outlet of the Remove the obstacles
heat exchanger
Check the service area
Check the speed (Outdoor
Replace the fan motor if
Fan: Cooling / Indoor Fan:
Heating)
Reduce the heat load or
Calculate the heat load
Check for hot air near the
Provide good circulation
ceiling (Heating)
Check for short-circuited air Remove the short-circuited
(Heating)
Check for other heat source Remove the heat source
Measure the discharge
pressure. Check the conti- Replace the pressure
nuity after the decrease of
the pressure
Measure the resistance by Fix the looseness. Replace
means of the tester
Check the connections Repair the connections
Check the cycle operation Charge the refrigerant
temp.
Check the air temp. and Recharge the refrigerant
the pressure after the vacuum pumping
Check for clogging
Check the stop valves Fully Open the stop valves
Check wiring
Repair connections. Re-
Check connections
Action
(Turn OFF the main
switch)
clogging
Remove the dust
Secure service area
faulty
use a bigger unit
air
switch if faulty
the connector
correctly
Remove the clogging
place Magnet Switch