Mitsubishi Electric PUHZ-P100VHA.UK Service Manual page 32

Error Code Meaning of error code and detection method
Abnormality in the outdoor fan motor
The outdoor fan motor is considered to be
abnormal if the rotational frequency of fan
motor is abnormal when detected during
operation.
Fan motor rotational frequency is abnor-
U8
(4400) mal if;
• 100 rpm or below detected continuously
for 15 seconds at 20: or more outside
air temperature
• 50 rpm or below or 1500 rpm or more
detected continuously for 1 minute.
Abnormality such as overvoltage or
voltage shortage and abnormal
synchronous signal to main circuit
Abnormal if any of followings are detected
during compressor operation;
• Decrease of DC bus voltage to 310V
• Instantaneous decrease of DC bus volt-
age
U9
to 200V
(4220)
• Increase of DC bus voltage to 400V
• Decrease of input current of outdoor unit
to 0.5A only if operation frequency is
more than or equal to 40Hz or compres-
sor
current is more than or equal to 5A.
Over heat protection
Abnormal if outdoor pipe thermistor (TH3)
detects 70: or more during compressor
Ud
operation.
(1504)
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
UF
after compressor starts operating.
(4100)
Compressor current sensor error or
input current error
Abnormal if compressor current sensor
detects –1.5A to 1.5A during compressor
UH
operation. (This error is ignored in case of
(5300)
test run mode.)
It's abnormal for 38A the input current or
10 seconds continuousnes 34A or more.
Abnormal low pressure
Abnormal if the following conditions are
detected for continuousness 3 minutes
after compressor starts heating operating
for 10 minutes.
(However, it becomes this abnormal detec-
tion disregard at the compressor driving
UL
time after it turns on power after 30 min-
(1300)
utes totaling. )
TH7-TH3[4:
TH5-Indoor room temperature[2:
Thermistor TH3:Outdoor liquid pipe temperature
TH5:Indoor cond./eva. Temperature
TH7:Outdoor temperature
Case
1 Failure in the operation of
the DC fan motor
2 Failure in the outdoor circuit
controller board
1 Decrease of power supply voltage
2 Disconnection of compressor
wiring
3 Defective 52C
4 Defective ACT module
5 Defective ACT module drive
circuit of outdoor power circuit
board
6 Disconnection or loose connec-
tion of CNAF
7 Defective 52C drive circuit of
outdoor controller circuit board
8 Disconnection or loose
connection of CN5 on the
outdoor power circuit board.
9 Disconnection or loose
connection of CN2 on the
outdoor power circuit board.
1 Defective outdoor fan (fan
motor) or short cycle of outdoor
unit during coling operation.
2 Defective outdoor pipe
thermistor (TH3)
3 Defective outdoor controller board
1 Stop valve is closed.
2 Decrease of power supply
voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective compressor
5 Defective outdoor power board
1 Disconnection of compressor
wiring
2 Defective circuit of current
sensor on outdoor power
circuit board
1 Stop valve of outdoor unit is
closed during operation.
2 Leakage or shortage of refriger-
ant
3 Malfunction of linear expansion
valve
32
Judgment and action
1 Check or replace the DC fan motor.
2 Check the voltage of the outdoor circuit
controller board during operation.
3 Replace the outdoor circuit controller
board. (when the failure is still indicated
even after performing the remedy 1
above.)
1 Check the facility of power supply.
2 Correct the wiring (U•V•W phase) to compressor.
Refer to 10-9 (Outdoor power circuit board).
3 Replace 52C.
4 Replace ACT module.
5 Replace outdoor power circuit board.
6 Check CNAF wiring.
7 Replace outdoor controller circuit board.
8 Check CN5 wiring on the outdoor power
circuit board.
Refer to 10-9.
9 Check CN2 wiring on the outdoor power
circuit board.
Refer to 10-9.
1 Check outdoor unit air passage
23 Put the power off and on again to check
the error code. If U4 is displayed, follow the
U4 processing direction.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U•V•W phase) to
compressor.
Refer to 10-9 (Outdoor power circuit board).
4 Check compressor.
Refer to 10-6.
5 Replace outdoor power circuit board.
1 Correct the wiring (U•V•W phase) to
compressor. Refer to 10-9 (Outdoor power
circuit board).
2 Replace outdoor power circuit board.
1 Check stop valve.
2 Check intake super heat.
Check leakage of refrigerant.
Charge additional refrigerant.
3 Check linear expansion valve.
Refer to 10-6.