Mitsubishi Electric MXZ-8B140VA Technical & Service Manual page 27

<Abnormalities detected while unit is operating>
Abnormal point and detection method
Error Code
(1) High-pressure switch (63H) operated
Abnormal if high-pressure switch 63H oper-
ated ( w ) during compressor operation.
w 4.15 MPa
63H: High-pressure switch
(2) High pressure
(High - pressure sensor 63HS detect)
1 When high-pressure sensor
detects 4.31MPa or more (or over
4.15MPa for 3 minutes) (1st detection)
during the compressor operation, the
compressor stops and restarts opera-
tion in 3 minutes.
2 When the sensor detects 4.31MPa or
more (or over 4.15MPa for 3 minutes)
again (2nd detection) within 30 minutes
since the compressor has stopped, the
compressor stops again and restarts
operation in 3 minutes.
3 When the sensor detects 4.31MPa or
more (or over 4.15MPa for 3 minutes)
U1
again (3rd detection) within 30 minutes
(1302)
since the compressor has stopped, the
compressor stops again and restarts
operation in 3 minutes.
4 When the sensor detects 4.31MPa or
more (or over 4.15MPa for 3 minutes)
again (4th detection) within 30 minutes
after 3rd compressor stop, it stops
abnormally. In this time <U1> is dis-
played.
5 When the sensor detects 4.31MPa or
more (or over 4.15MPa for 3 minutes)
after 30 minutes since the compressor
has stopped (1st or 2nd or 3rd time), it
becomes the 1st detection or the same
performance as above-mentioned 1.
6 It is being delay for abnormal stop during
30 minutes since the compressor has
stopped. In this time, check delay code
<U1> will be displayed.
OCH480A
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 fully opened)
8) Clogged or broken pipe
9) Locked outdoor fan motor
10) Malfunction of outdoor fan
motor
11) Short cycle of outdoor unit
12) Dirt of outdoor heat exchang-
er
13) Decreased airflow caused by
defective inspection of out
side temperature thermistor
(It detects lower temperature
than actual temperature.)
14) Disconnection or contact
failure of connector (63H) on
outdoor controller board
15) Disconnection or contact fail-
ure of 63H connection
16) Defective outdoor controller
board
17) Defective action of linear
expansion valve
18) Malfunction of fan driving cir-
cuit
19) Solenoid valve (SV1) per-
formance failure (High-
pressure cannot be controlled
by SV1)
20) High-pressure sensor defec-
tive
21) High-pressure sensor input
circuit defective in multi con-
troller board
27
Judgment and action
1)~6) Check indoor unit and repair defect.
7) Check if stop valve is fully open.
8) Check piping and repair defectives.
9)~12) Check outdoor unit and repair defect.
13) Check the detected temperature of outside
temperature thermistor on LED display.
14)~16) Put the power off and check F5 is
displayed when the power is put again.
When F5 is displayed, refer to
"Judgment and action" for F5.
17) Check linear expansion valve.
Refer to 8-6.
18) Replace outdoor controller board.
19) Check the solenoid valve performance.
20) Check the high-pressure sensor.
21) Check the high-pressure sensor.