Mitsubishi Electric Mr.SLIM PUZ-A42NHA5-BS Service Manual page 29

<Abnormalities detected while unit is operating>
Abnormal point and detection method
Error Code
High pressure (High-pressure switch
63H operated)
Abnormal if high-pressure switch 63H oper-
ated ( w ) during compressor operation.
w 4.15 MPa [602PSIG]
63H: High-pressure switch
U1
(1302)
High comp.shell temperature
Abnormal if comp.shell temperature
thermistor (TH32) exceeds 125: [257˚F].
U2
(TH32: 1132)
Open/short circuit of comp.shell
thermistor (TH32)
Abnormal if open (3: [37˚F] or less) or
short (217: [422˚F] or more) is detected
during compressor operation.
(Detection is inoperative for 10 minutes
U3
of compressor starting process and for 10
(TH32: 5132)
minutes after and during defrosting.)
OCH512
Case
1 Short cycle of indoor unit
2 Clogged filter of indoor unit
3 Decreased airflow caused by
dirt of indoor fan
4 Dirt of indoor heat exchanger
5 Locked indoor fan motor
6 Malfunction of indoor fan motor
7 Defective operation of stop
valve (Not full open)
8 Clogged or broken pipe
9 Locked outdoor fan motor
0 Malfunction of outdoor fan
motor
1 Short cycle of outdoor unit
2 Dirt of outdoor heat exchanger
3 Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
4 Disconnection or contact failure
of connector (63H) on outdoor
controller board
5 Disconnection or contact failure
of 63H connection
6 Defective outdoor controller
board
7 Defective action of linear
expansion valve
8 Malfunction of fan driving circuit
1 Overheated compressor opera-
tion caused by shortage of
refrigerant
2 Defective operation of stop
valve
3 Defective thermistor
4 Defective outdoor controller
board
5 Defective action of linear
expansion valve
1 Disconnection or contact failure
of connector (TH32) on the
outdoor controller circuit board
2 Defective thermistor
3 Defective outdoor controller
circuit board
29
Judgment and action
1~6 Check indoor unit and repair the defect.
7 Check if stop valve is fully open.
8 Check piping and repair the defect.
9~2 Check outdoor unit and repair the defect.
3 Check the inspected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer to
10-10.)
4~6 Turn the power off and check F5 is
displayed when the power is on again.
When F5 is displayed, refer to "Judgment
and action" for F5.
7 Check linear expansion valve.
Refer to 10-6, 7.
8 Replace outdoor controller board.
1 Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
2 Check if stop valve is fully open.
34 Turn the power off and check if U3 is dis-
played when the power is on again.
When U3 is displayed, refer to "Judgement
and action" for U3.
5 Check linear expansion valve.
Refer to 10-6, 7.
1 Check connection of connector (TH32) on the
outdoor controller circuit board.
Check breaking of the lead wire for thermistor
(TH32). Refer to 10-9.
2 Check resistance value of thermistor (TH32)
or temperature by microprocessor.
(Thermistor/TH32: Refer to 10-6.)
(SW2 on A-Control Service Tool: Refer to
10-10.)
3 Replace outdoor controller board.