
10 Troubleshooting
Initial troubleshooting
SMGB0091 rev.2 - 11/2015
194
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Insufficient heating process
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
indoor unit
Remove the obstacles
Check the indoor fan speed
Replace the fan motor
Excessively high
air temperature
to the indoor unit
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
*1)
Correctly charge the refrigerant
Non-condensate
gas in refrigerant
cycle
Check the refrigerant quantity
*1)
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 RASC unit
Check the temperature
difference at the inlet and the
outlet of the check valve
Replace the check valve
Excessively high
suction 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
?
N O T E
“3.4.1 Refrigerant charge amount”
in this document.
Cooling or heating process
with an abnormal sound
Foreign particles inside of the fan
casing
Visually inspect it
Remove the foreign particles
Indoor unit fan runner is hitting the
casing
Visually inspect it
Adjust the position of the fan
runner
RASC unit fan runner is hitting the
casing
Visually inspect it
Adjust the position of the fan
runner
Abnormal
sound from the
compressor
Faulty
Installation
Check that each part is tightly
fixed
Tightly fix each part
Liquid refrigerant
compression
Adjust the suction gas temp.
and pressure
Ensure superheat
Wear or
breakage of
the internal
compressor
parts
Abnormal sound from the
inside of the compressor
Replace the compressor
No heating by
the oil heater
Check the resistance (oil
heater, fuse)
Replace the oil heater or the
fuse
Humming sound from the magnetic
conductor
Check the surface of the
contacts
Replace the magnetic switch
Abnormal vibration of the cabinets
Check each fixing screw
Tightly fix each screw