Mitsubishi Electric PUHZ-SW75VAA-SC Service Manual page 31

9-3. TROUBLESHOOTING OF PROBLEMS
Phenomena
1. Remote controller display does not
work.
2. "PLEASE WAIT" display is remained
on the remote controller.
3. When pressing the remote controller
operation switch, the OPERATION dis-
play is appeared but it will be turned
off soon.
4. Remote controller display works
normally and the unit performs cooling
operation, however, the capacity
cannot be fully obtained.
5. Remote controller display works
normally and the unit performs heating
operation, however, the capacity
cannot be fully obtained.
6. 1 For 3 minutes after temperature
adjuster turns off, the compressor
will not start operating even if
temperature adjuster is turned on.
2 For 3 minutes after temperature
adjuster turns on, the compressor
will not stop operating even if
temperature adjuster is turned off.
(Compressor stops operating
immediately when turning off by the
remote controller.)
OCH651A
Factor
1 1 2 V DC is not supplied to remote controller.
2 1 2–15 V DC is supplied to remote controller,
however, no display is indicated.
• "PLEASE WAIT" is not displayed.
• "PLEASE WAIT" is displayed.
1 At longest 2 minutes after the power supply
"PLEASE WAIT" is displayed to start up.
2 Communication error between the remote
controller and indoor unit
3 Communication error between the indoor and
outdoor unit
4 Outdoor unit protection device connector is
open.
1 After cancelling to select function from the
remote controller, the remote controller opera-
tion switch will be not accepted for approx. 30
seconds.
1 Refrigerant shortage
2 Filter clogging
1 Linear expansion valve fault
Opening cannot be adjusted well due to linear
expansion valve fault.
2 Refrigerant shortage
3 Lack of insulation for refrigerant piping
4 Filter clogging
5 Bypass circuit of outdoor unit fault
12 Normal operation
(For protection of compressor)
31
Countermeasure
1 Check LED2 on indoor controller board.
(1) When LED2 is lit.
Check the remote controller wiring for break-
ing or contact failure.
(2) When LED2 is blinking.
Check short circuit of remote controller
wiring.
(3) When LED2 is not lit.
Refer to No.3 below.
2 Check the following.
• Failure of remote controller if "PLEASE WAIT"
is not displayed
• Refer to No.2 below if "PLEASE WAIT" is dis-
played.
1 Normal operation
2 Self-diagnosis of remote controller
3 "PLEASE WAIT" is displayed for 6 minutes
at most in case of indoor/outdoor unit
communication error. Check LED3 on indoor
controller board.
(1) When LED3 is not blinking.
Check indoor/outdoor connecting wire for
miswiring.
(Converse wiring of S1 and S2, or break of
S3 wiring.)
(2) When LED3 is blinking.
Indoor/outdoor connecting wire is normal.
4 Check LED display on outdoor controller circuit
board. Refer to "9-9.TEST POINT DIAGRAM".
Check protection device connector (63L and
63H) for contact failure.
1 Normal operation
1 If refrigerant leaks, discharging temperature
rises and LEV opening increases.
Inspect leakage by checking the temperature
and opening.
Check pipe connections for gas leakage.
2 Clean the filter of water piping.
1 Discharging temperature and indoor heat
exchanger temperature does not rise.
Inspect the failure by checking discharging
pressure.
Replace linear expansion valve.
2 If refrigerant leaks, discharging temperature
rises and LEV opening increases.
Inspect leakage by checking the temperature
and opening.
Check pipe connections for gas leakage.
3 Check the insulation.
4 Clean the filter of water piping.
5 Check refrigerant system during operation.
12 Normal operation