Mitsubishi Electric PUHZ-ZRP35VKA2 Service Manual page 36

Check Code Abnormal points and detection method
Over heat protection
Abnormal if outdoor pipe thermistor (TH3)
detects 70: or more during compressor
operation.
Ud
(UD)*
(1504)
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
UF
(4100)
Current sensor error
Abnormal if current sensor detects −1.0 A
to 1.0 A during compressor operation. (This
error is ignored in case of test run mode.)
UH
(5300)
Low pressure
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts heating operating for 10
minutes.
1. Heating mode
Detection mode 1
TH7−TH3 [ 4°C and
TH5−Indoor room temperature [ 2°C
Detection mode 2
TH7−TH3 [ 2°C and
TH5−Indoor room temperature [ 4°C
and
TH2−Indoor room temperature [ 4°C
Detection mode 3
UL
TH7−TH3 [ 4°C and
(1300)
TH5−Indoor room temperature [ 2°C
and TH4−TH5 ] 20°C
2. Cooling mode
TH6−TH7 [ 2°C and
TH3−TH7 [ 2°C and
Indoor room temperature - Indoor liquid
pipe temperature (TH2) [ 5°C
Thermistor TH3: Outdoor liquid pipe temperature
TH4: Discharge temperature
TH5: Indoor cond./eva. temperature
TH6: Outdoor 2-phase pipe temperature
TH7: Outdoor temperature
OCH635A
Cause
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 con-
verse of compressor wiring connec-
tion
4 Defective compressor
5 Defective outdoor power board
6 DIP switch setting difference of out-
door controller circuit 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 refrigerant
3 Malfunction of linear expansion valve
4 Clogging with foreign objects in
refrigerant circuit
Note:
Clogging occurs in the parts which
become below freezing point when
water enters in refrigerant circuit.
36
Judgment and action
1 Check outdoor unit air passage.
23 Turn the power off, and on again to
check the check code. If U4 is displayed,
follow the U4 processing direction.
* The check code in the parenthesis indi-
cates PAR-30/31MAA model.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U
V W phase) to
• •
compressor.
Refer to "10-9. TEST POINT DIAGRAM".
(Outdoor power circuit board).
4 Check compressor.
Refer to "10-6. HOW TO CHECK THE
PARTS".
5 Replace outdoor power circuit board.
6 Check the dip switch setting of outdoor con-
troller circuit board.
Refer to "Model Select" in "1) Function of
switches" in Refer to "10-10. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".
1 Correct the wiring (U V W phase) to
• •
compressor. Refer to "10-9. TEST
POINT DIAGRAM". (Outdoor power
circuit board).
2 Replace outdoor power circuit board.
1 Check stop valve.
2 Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
3 Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS".
4 After recovering refrigerant, remove
water from entire refrigerant circuit under
vacuum more than 1 hour.