Hitachi RAS-(2-6)HVNP1(E), Руководство по обслуживанию

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8 Troubleshooting
214
SMGB0087 rev.0 - 12/2013
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Insufficient heating
process
Indoor heat load is greater than the heating
capacity
Calculate the heat load
Replace the unit with a
bigger unit
Excessively low
suction pressure
Gas leakage or
insufficient refrigerant
charge
Measure superheat
Correctly charge the
refrigerant after the gas leak-
age check and repairing
Excessively small
diameter or long
piping
Measure the field supplied
piping
Use the specified pipes
Failure or malfunc-
tion of the expansion
valve
Check for clogging Remove the clogging
Check the connection cord
and the connector
Replace the connector
Is there an operation sound
from the coil?
Replace the coil
Is the thermistor on the
compressor normal?
Replace the thermistor
Is the thermistor installed
correctly on compressor?
Correctly install the
thermistor
Clogging of IU/OU
strainer
Check the temperature dif-
ference between the inlet
and the outlet of strainer
Replace the strainer for the
outdoor unit or the indoor unit
Clogging of suction
piping
Check the temperature dif-
ference of each part
Remove the clogging
Insufficient air flow
through the outdoor
unit heat exchanger
Is the outdoor unit heat
exchanger clogged?
Remove the clogging
Are there any obstacles at
the inlet or the outlet of
outdoor unit?
Remove the obstacles
Is the service area for the
outdoor unit sufficient?
Secure a sufficient service
area
Check the speed of the
outdoor unit fan
Replace the fan motor
Excessively low air
temperature through
the outdoor unit heat
exchanger
Check for any short-circuited
air to the outdoor unit
Remove the cause of the
short-circuited air
Defrosting is insuffi-
ciently completed
Check the thermistor for the
defrost operation
Replace the thermistor for
the defrost operation
Excessively high
discharge pressure
Insufficient air flow to
the indoor unit heat
exchanger
Check the filter for a clogging Remove the clogging
Check for any obstacles at
the inlet or the outlet of the IU Remove the obstacles
Check the indoor fan speed Replace the fan motor
Excessively high air
temperature to the IU
heat exchanger
Check whether or not the
short-circuited air exists
Remove the cause of the
short-circuited air
Excessively charged
refrigerant
Check the refrigerant
quantity *4)
Correctly charge the refrigerant
Non-condensate gas
in refrigerant cycle
Check the refrigerant
quantity *4)
Recharge the refrigerant after
the vacuum pumping
Clogging of the
discharge pressure
piping
Check for clogging Remove the clogging
Malfunction or internal leakage of the 4-way
valve
Check the temperature
difference at the inlet and the
outlet of the 4-way valve
Replace the 4-way valve
Malfunction of the check valve of the outdoor
unit
Check the temperature
difference at the inlet and the
outlet of the check valve
Replace the check valve
Excessively high suc-
tion pressure
Malfunction or
internal leakage of
4-way valve
Check the temperature
difference at the inlet and the
outlet of the 4-way valve
Replace the 4-way valve
Discharge temperature of the indoor unit is
unstable
Check the expansion valve
of the indoor unit in the same
system
Replace the failed expansion
valve of the indoor unit