Cooling - Mitsubishi Electric PUZ-A18NHA4 Service Manual

Phenomena
4. Even controlling by the wireless
remote controller no beep is heard
and the unit does not start operat-
ing. Operation display is indicated
on wireless remote controller.
5. When operating by the wireless
remote controller, beep sound is
heard, however, unit does not start
operating.
6. Remote controller display works
normally and the unit performs cool-
ing operation, however, the capacity
cannot be fully obtained. (The air
does not cool well.)
7. Remote controller display works
normally and the unit performs heat-
ing operation, however, the capacity
cannot be fully obtained.
8. 1For 3 minutes after temperature
adjuster turns off, the compressor
will not start operating even if
temperature adjuster is turned on.
2For 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.)
Factor
1The pair number settings of the wireless remote
controller and indoor controller board are mismatched.
1No operation for 2 minutes at most after the power
supply ON.
2Hand-held remote controller operation is prohibited.
• Remote controlling adaptor is connected to CN32
on the indoor controller board.
• Hand-held remote controller operation is prohibited
by centralised controller etc. since it is connected to
MELANS.
3Refer to factor of phenomena No.2 on previous page.
1Refrigerant shortage
2Filter clogging
3Heat exchanger clogging
4Air duct short cycle
1Linear expansion valve fault
Opening cannot be adjusted well due to linear expan-
sion valve fault.
2Refrigerant shortage
3Lack of insulation for refrigerant piping
4Filter clogging
5Heat exchanger clogging
6Air duct short cycle
7Bypass circuit of outdoor unit fault
12Normal operation
(For protection of compressor)
1Check the pair number settings.
1Normal operation
2Normal operation
3Check the details of phenomena No.2 on
previous page.
1 If refrigerant leaks, discharging tempera-
ture rises and LEV opening increases.
Inspect leakage by checking the tempera-
ture and opening.
Check pipe connections for gas leakage.
2 Open intake grille and check the filter.
Clean the filter by removing dirt or dust
on it.
3 If the filter is clogged, indoor pipe tem-
perature rises and discharging pressure
increases. Check if heat exchanger is
clogged by inspecting discharging pres-
sure.
Clean the heat exchanger.
4 Remove the shield.
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 tempera-
ture rises and LEV opening increases.
Inspect leakage by checking the tempera-
ture and opening.
Check pipe connections for gas leakage.
3 Check the insulation.
4 Open intake grill and check the filter. Clean
the filter by removing dirt or dust on it.
5 If the filter is clogged, indoor pipe tem-
perature rises and discharging pressure
increases. Check if heat exchanger is
clogged by inspecting discharging pres-
sure.
Clean the heat exchanger.
6 Remove the shield.
7 Check refrigerant system during operation.
12Normal operation
46
Countermeasure