Mitsubishi Electric PUZ-SWM60VAA Service Manual page 26

<Abnormalities detected while unit is operating>
Check code Abnormal point and detection method
High pressure (High pressure switch
63H operated)
Abnormal if high pressure switch 63H
operated (4.80 MPa) during compressor
operation.
63H: High pressure switch
U1
(1302)
High discharge temperature
1. Abnormal if TH4 exceeds 125°C or
110˚C continuously for 5 minutes.
Abnormal if TH4 exceeds 110°C or
more continuously for 30 seconds after
90 seconds have passed since the
defrosting operation started.
2. Abnormal if discharge superheat
(Heating: TH4−T63HS)
exceeds 70°C continuously for 10
U2
minutes.
(TH4:1102)
(TH33:1132)
TH4: Thermistor <Discharge>
High comp. surface temperature
Abnormal if TH33 exceeds 125°C.
In the case of high comp. surface
temperature error, compressor does
not restart unless the thermistor (TH33)
becomes less than 95°C.
TH33: Thermistor <Comp. surface>
Open/short circuit of outdoor unit
temperature thermistor (TH4, TH33)
Abnormal if open (-20°C or less) or short
(217°C or more) is detected during
compressor operation.
(Detection is inoperative for 10 minutes of
U3
compressor starting process and for 10
(TH4:5104)
minutes after and during defrosting.)
(TH33:5132)
TH4: Thermistor <Discharge>
TH33: Thermistor <Comp. surface>
OCH809A
Cause
Short cycle of indoor unit
Clogged filter of indoor unit
Decreased airflow caused by
dirt of indoor fan
Dirt of indoor heat exchanger
Locked indoor fan motor
Malfunction of indoor fan motor
Defective operation of stop
valve (Not fully open)
Clogged or broken pipe
Locked outdoor fan motor
Malfunction of outdoor fan
motor
Short cycle of outdoor unit
Dirt of outdoor heat exchanger
Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
Disconnection or contact failure
of connector (63H) on outdoor
controller board
Disconnection or contact failure
of 63H connection
Defective outdoor controller
board
Defective action of linear
expansion valve
Malfunction of fan driving circuit
Overheated compressor
operation caused by shortage
of refrigerant
Defective operation of stop
valve
Defective thermistor
Defective outdoor controller
board
Defective action of linear
expansion valve
Clogging with foreign objects in
refrigerant circuit
Note: Clogging occur in the parts
which become below
freezing point when water
enters in refrigerant circuit.
In the case of the unit does not
restart:
Detection temp. of thermistor
(TH33) ≥ 95°C
Disconnection or contact failure
of connectors (TH4, TH33) on
the outdoor controller circuit
board
Defective thermistor
Defective outdoor controller cir-
cuit board
26
Judgment and action
– Check indoor unit and repair defect.
Check if stop valve is fully open.
Check outdoor unit and repair defect.
– Check outdoor unit and repair defect.
Check the detected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool: Refer to
"9-7. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
– Turn the power off and check F5 is
displayed when the power is turned again.
When F5 is displayed, refer to "Judgment
and action" for F5.
Check linear expansion valve.
Refer to "9-4. HOW TO CHECK THE PARTS".
Replace outdoor controller board.
Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
Check if stop valve is fully open.
Turn the power off and check if U3 is
displayed when the power is turned on again.
When U3 is displayed, refer to "Judgment
and action" for U3.
Check linear expansion valve.
Refer to "9-4. HOW TO CHECK THE PARTS".
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
Check connection of connector (TH4, TH33) on
the outdoor controller circuit board.
Check breaking of the lead wire for
TH4, TH33. Refer to "9-6.TEST POINT
DIAGRAM".
Check resistance value of TH4, TH33 or
temperature by microprocessor.
(Thermistor/TH4, TH33: Refer to "9-4. HOW TO
CHECK THE PARTS".) (SW2 on A-Control
Service Tool: Refer to "9-7. FUNCTION OF
SWITCHES, CONNECTORS AND JUMPERS".)
Replace outdoor controller board.