Abnormalities Detected While Unit Is Operating; High Pressure; High Discharging Temperature; Open/Short Circuit Of Discharge - Mitsubishi Electric PUHZ-SW40VHA Service Manual

<Abnormalities detected while unit is operating>
Abnormal points and detection method
Error Code
High pressure (High-pressure switch
63H operated)
Abnormal if high-pressure switch 63H
operated ( w ) during compressor opera-
tion.
w SW40,50 (63H) : 4.15 MPa
63H: High-pressure switch
U1

High discharging temperature

(1) Abnormal if discharge temperature
thermistor (TH4) exceeds 125: or
110: continuously for 5 minutes.
Abnormal if discharge temperature
thermistor (TH4) exceeds 110: or
more continuously for 30 seconds
after 90 seconds have passed since the
defrosting operation started.
(2) Abnormal if discharge superheat
(Cooling: TH4 – T
U2
Heating: TH4 – T
continuously for 10 minutes.
High comp. surface temperature
Abnormal if comp. surface temperature
(TH34) exceeds 125:.In the case of
high comp. surface temperature error,
compressor does not restart unless the
thermistor (TH34) becomes less than
95:.

Open/short circuit of discharge

temperature thermistor (TH4) / comp.
surface thermistor (TH34)
Abnormal if open (3: or less) or short
(217: or more) is detected during
U3
compressor operation.
(Detection is inoperative for 10 minutes
of compressor starting process and for 10
minutes after and during defrosting.)
OCH525
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
operation 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
/
63HS
6 Clogging with foreign objects in
) exceeds 70:
63HS
refrigerant circuit
w Clogging occur in the parts
which become below freezing
point when water enters in
refrigerant circuit.
1 Disconnection or contact failure
of connector (TH4/TH34) on
the outdoor controller circuit
board
2 Defective thermistor
3 Defective outdoor controller
circuit board
Case
1~6 Check indoor unit and repair defect.
7 Check if stop valve is fully open.
8 Check piping and repair defect.
9~2 Check outdoor unit and repair defect.
3 Check the detected temperature of outside
4~6 Turn the power off and check F5 is
7 Check linear expansion valve.
8 Replace outdoor controller board.
1 Check intake superheat.
2 Check if stop valve is fully open.
34 Turn the power off and check if U3 is
5 Check linear expansion valve.
6 After recovering refrigerant, remove water
1 Check connection of connector (TH4/TH34)
2 Check resistance value of thermistor (TH4/
3 Replace outdoor controller board.
17
Judgment and action
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer to
10-10.)
displayed when the power is turned again.
When F5 is displayed, refer to "Judgment
and action" for F5.
Refer to 10-6.
Check leakage of refrigerant.
Charge additional refrigerant.
displayed when the power is turned on again.
When U3 is displayed, refer to "Judgement
and action" for U3.
Refer to 10-6.
from entire refrigerant circuit under vacuum
more than 1 hour.
on the outdoor controller circuit board.
Check breaking of the lead wire for
thermistor (TH4/TH34). Refer to 10-9.
TH34) or temperature by microcomputer.
(Thermistor/TH4/TH34: Refer to 10-6.)
(SW2 on A-Control Service Tool: Refer to 10-10.)