Mitsubishi Electric Mr.Slim PUH-P25VGAA Service Manual page 46

Phenomena
(7)Left/right louver performance fault.
(8)Though the remote controller dis-
play is normal in cool mode, the
capacity is not enough.
(9)Though the remote controller dis-
play is normal in Heat mode, the
capacity is not enough.
Factor
1Louver motor fault.
2Disconnecting, breaking and contact fault of the con-
nector.
1Filter clogging (dirt)
2Heat exchanger clogging (dirt)
3Air duct short cycle.
4Refrigerant shortage.
5Operation failure in electronic expansion valve
6Thermistor connection failure
7Incorrect piping size
8Piping is too long.
1Filter clogging (dirt)
2Heat exchanger clogging (dirt)
3Air duct short cycle.
4Refrigerant shortage.
5Outdoor unit bypass circuit failure
6Indoor reverse check valve failure
Reverse check valve failure may cause refrigerant
leakage and restrictor failure.
7Heat insulator of refrigerant pipes is defective.
8Malfunction of LEV.
9Loose connection in thermistor.
1Louver motor resistance value check
2Check the removing of indoor controller
board (CNL) breaking line and contact
fault.
1Open the grille to check the filter.
Clean the filter and remove dust or dirt
away.
2Clean the heat exchanger.
Lowering the indoor piping temperature
and intake pressure means clogging in the
heat exchanger.
3Remove screen in the air duct (air outlet/
intake).
4Check if gas leaks or not in the piping
joint.
5,6Check the refrigerant circuit operation
status.
7Check the piping size.
8Check the capacity loss characteristic for
the piping length.
1Open the grille to check the filter.
Clean the filter and remove dust or dirt
away.
2Clean the heat exchanger.
Rising the indoor piping temperature and
outlet pressure means clogging in the heat
exchanger.
3Remove screen in the air duct (air outlet/
intake).
4Check if gas leaks or not in the piping
joint.
5Operating condition check in the refriger-
ant cycle.
6Since outlet temperature and indoor heat
exchanger temperature does not rise,
measure the outlet pressure and deter-
mine the countermeasure.
7Check the heat insulator.
8,9Check the function of refrigerant circuit.
46
Countermeasure