Abnormalities Detected While Unit Is Operating - Mitsubishi Electric PUHZ-HRP71VHA Service Manual

<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
operated ( ) during compressor operation.
*
* 4.15 MPa
63H: High-pressure switch
U1
(1302)
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.
U2
(1102)
(2) Abnormal if discharge superheat
(Cooling: TH4 – TH6 / Heating: TH4 –
TH5) (V/YHA)
(Cooling: TH4 – T
T ) (V/YHA2)
63HS
exceeds 70: continuously for 10
minutes.
Open/short circuit of discharge
temperature thermistor (TH4)
Abnormal if open (3: or less) or short
(217: or more) is detected during
compressor operation.
(Detection is inoperative for 10 minutes
U3
of compressor starting process and for 10
(5104)
minutes after and during defrosting.)
OCH425F
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
6 Clogging with foreign objects in
refrigerant circuit
/ Heating: TH4 – * Clogging occur in the parts
63HS
which become below freezing
point when water enters in
refrigerant circuit.
1 Disconnection or contact
failure of connector (TH4) 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
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer to
11-10.)
4~6 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.
7 Check linear expansion valve.
Refer to 11-6.
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
displayed when the power is turned on again.
When U3 is displayed, refer to "Judgement
and action" for U3.
5 Check linear expansion valve.
Refer to 11-6.
6 After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
1 Check connection of connector (TH4) on the
outdoor controller circuit board.
Check breaking of the lead wire for
thermistor (TH4). Refer to 11-9.
2 Check resistance value of thermistor (TH4)
or temperature by microprocessor.
(Thermistor/TH4: Refer to 11-6.)
(SW2 on A-Control Service Tool: Refer to 11-10.)
3 Replace outdoor controller board.
42
Judgment and action