Mitsubishi Electric MXZ-SM72TAM-U1 Service Manual page 38

1302 (UE): High pressure trouble
Abnormal points and detection methods
• High pressure abnormality (63H operation)
63H operates(*) during compressor operation.
(* 602 psig [4.15 MPaG])
• High pressure abnormality (63HS detected)
- A pressure detected by 63HS is 625 psig (4.31
MPaG) or more during compressor operation.
- A pressure detected by 63HS is 600 psig (4.14
MPaG) or more for 3 minutes during compressor
operation.
63H:
High pressure switch
63HS:
High pressure sensor
LEV:
Linear expansion valve
SV1:
Solenoid valve
TH7:
Thermistor <Ambient>
TRS:
Thermal protector
Diagnosis of failure
Turn OFF the power of indoor/outdoor
unit, Fresh Master, Lossnay and
remote controller simultaneously for
10 minutes, then turn the power back
ON.
Is the error code <6607> No ANC
error displayed ?
Is the error code 5201 displayed when
restarted?
Is the outdoor stop valve (liquid/gas)
fully open?
Does the outdoor fan rotate during the
operation?
Does the indoor fan rotate during the
operation?
Is the indoor unit short-cycled?
Continue to the next page.
OCH800A_38
Yes
No
Yes
(5201)
No
(1302)
No
Yes
No
Yes
No
Yes
Yes
(Short-cycled)
No
(Not short-cycled)
Causes and checkpoints
• Faulty operation of stop valve (not fully open)
• Clogged or broken pipe
• Malfunction or locked outdoor fan motor
• Short-cycle of outdoor unit
• Dirt of outdoor heat exchanger
• Remote controller transmitting error caused by noise
interference
• Contact failure of the outdoor multi controller circuit
board connector
• Defective outdoor multi controller circuit board
• Short-cycle of indoor unit
• Decreased airflow, clogged filter, or dirt on indoor unit
• Malfunction or locked indoor fan motor
• Decreased airflow caused by faulty inspection of out-
door temperature thermistor (It detects lower tempera-
ture than actual temperature.)
• Indoor LEV performance failure
• Malfunction of fan driving circuit
• SV1 performance failure
• Defective High pressure sensor
• Defective High pressure sensor input circuit on outdoor
multi controller circuit board
• High compressor temperature (Thermal protector TRS
operated)
There is abnormality in circuit board or wiring
connection on the outdoor unit.
Refer to the diagnosis of error code 5201.
Open the stop valve (liquid/gas) fully.
Check the outdoor fan motor.
Refer to "How to check the parts" on the outdoor
unit service manual.
Check the indoor fan motor.
Refer to "How to check the parts" on the indoor
unit service manual.
Resolve the short-cycle.
Chart 1 of 4