Troubleshooting - Mitsubishi Electric CITY MULTI PEFY-P-NMLU-E Series Operation Manual

6. Troubleshooting

Before you ask for repair service, check the following points:
State of Machine Remote Controller
" " display is not lit up
No display
It does not run.
even when the [ON/
OFF] Button is pressed.
Air flows out but it The liquid crystal dis-
does not cool enough play shows that it is in
or heat enough. the state of operation.
The liquid crystal dis-
Cool air or warm air
play shows that it is in
does not come out.
operation.
The "check" and check
It runs briefly, but soon
code flashes on the liq-
stops.
uid crystal display.
The sound of the
exhaust and rotation All lights are out except
of the motor can still the powered display of
be heard after stop of " ".
running.
The sound of the
exhaust and the rota- All lights are out except
tion of the motor can the powered display of
be heard intermittently " ".
after stop of running.
Warm air comes out
intermittently when The liquid crystal dis-
the thermostat is OFF play shows that it is in
or during fan opera- the state of operation.
tion.
• If operation stops due to a power failure, the [restart-preventing circuit at power failure] operates and disables unit operation even after power restoration. In this case,
press the [ON/OFF] Button again and start operation.
If malfunctions persist after you have checked the above, turn the power supply OFF and contact your dealer with information about the product name, the nature of the
malfunction, etc. If the display of "[check]" and (4 digit) check code flashes, tell the dealer contents of the display (check code). Never attempt to repair by yourself.
The following symptoms are not air-conditioner failures:
• The air blown out from the air-conditioner can sometimes give off odors. This is due to cigarette smoke contained in the air of the room, the smell of cosmetics, the
walls, furniture, etc., absorbed in the air-conditioner.
• A hissing noise can be heard immediately after the air-conditioner is started or stopped. This is the sound of the refrigeration flowing inside the air-conditioner. This is
normal.
• The air-conditioner sometimes snaps or clicks at the beginning or end of cooling/heating operation. This is the sound of friction on the front panel and other sections
due to expansion and contraction caused by temperature change. This is normal.
8
Cause
Power failure
appears The power supply is turned OFF.
The fuse in the power supply is gone.
The earth leakage breaker is gone.
Improper temperature adjustment.
The filter is filled with dust and dirt.
There are some obstacles at the air inlet and outlet of
the indoor and outdoor units.
Windows and doors are open.
The restart-preventing circuit is in operation for 3 min-
utes.
Indoor unit operation was started anew during the
heating and defrosting operation.
There are some obstacles at the air inlet and outlet of
the indoor and outdoor units.
The filter is filled with dust and dirt.
When other indoor units are engaged in cooling oper-
ation, the machine stops after running a drain-up
mechanism for 3 minutes when air-cooling operation
is stopped.
When other indoor units are engaged in cooling oper-
ation, drained water is brought in. If the drain water is
collected, the drain-up mechanism initiates a draining
operation.
When other indoor units are engaged in heating oper-
ation, the control valves are opened and closed from
time to time to maintain the stability of the system.
Troubleshooting
Press the [ON/OFF] Button after power restoration.
Turn the power supply ON.
Replace fuse.
Put in the earth leakage breaker.
After checking the set temperature and inlet temperature
on the liquid crystal display, refer to [Room temperature
adjustment], and operate the adjustment Button.
Clean up the filter.
(Refer to [Caring for the machine].)
Remove.
Close.
Wait for a while.
(To protect the compressor, a 3-minute restart-prevent-
ing circuit is built into the indoor unit. Therefore, there
are occasions sometimes when the compressor does
not start running immediately. There are cases when it
does not run for as long as 3 minutes.)
Wait for a while.
(Heating operation starts after ending defrosting opera-
tion.)
Rerun after removal.
Rerun after cleaning the filter. (Refer to [Caring for the
machine].)
Wait for 3 minutes.
It soon stops. (If the noise occurs more than 2-3 times in
an hour, ask for repair service.)
It soon stops. (If the room temperature rises uncomfort-
ably high in a small room, stop operation.)