Mitsubishi Electric Mr.Slim PUHZ-P100VHA2 Service Manual page 34

Abnormal points and detection method
Error Code
Outdoor fan motor
Abnormal if rotational frequency of the fan
motor is not detected during DC fan motor
operation.
Fan motor rotational frequency is abnormal if;
U8
• Less than 100 rpm detected continuously
(4400)
for 15 seconds at 20: or more outside
air temperature
• Less than 50 rpm or more than 1500 rpm
detected continuously for 1 minute.
Overvoltage or voltage shortage and
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 to 200V
• Increase of DC bus voltage to 400V
• Decrease of input current of outdoor unit
U9
to 0.5A only if operation frequency is
(4220)
more than or equal to 40Hz or compres-
sor current is more than or equal to 5A.
Overheat 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.)
Abnormal if the input current of 38A is
detected or the input current of 34A or
more is detected for 10 seconds.
Low pressure
Abnormal if the following conditions are
detected for 3 minutes continuously after
compressor starts heating operation for 10
minutes.
(However, this abnormal detection is disre-
garded when the compressor driving time
UL
exceeds 30 minutes after power is on.)
(1300)
TH7-TH3[4:
TH5-Indoor room temperature[2:
Thermistor TH3:Outdoor liquid pipe temperature
TH5:Indoor cond./eva. Temperature
TH7:Outdoor temperature
* In case of UL error, the compressor may be
damaged if the unit is restarted by remote
controller. To avoid the damage, unit has
the system that is not able to be restarted
unless the power is turned OFF once. .
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 noise filter circuit
board
4 Disconnection or loose connec-
tion of CN52C
5 Defective ACT module
6 Defective ACT module drive circuit
of outdoor power circuit board
7 Disconnection or loose connec-
tion of CNAF
8 Defective 52C drive circuit of
outdoor controller circuit board
9 Disconnection or loose
connection of CN5 on the
outdoor power circuit board
0 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 cooling 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
34
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 11-9 (Outdoor power circuit board).
3 Replace noise filter circuit board.
4 Check CN52C wiring.
5 Replace ACT module.
6 Replace outdoor power circuit board.
7 Check CNAF wiring.
8 Replace outdoor controller circuit board.
9 Check CN5 wiring on the outdoor power
circuit board.
Refer to 11-9.
0 Check CN2 wiring on the outdoor power
circuit board.
Refer to 11-9.
1 Check outdoor unit air passage.
23 Turn 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 11-9 (Outdoor power circuit board).
4 Check compressor.
Refer to 11-6.
5 Replace outdoor power circuit board.
1 Correct the wiring (U·V·W phase) to
compressor. Refer to 11-9 (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 11-6.