Mitsubishi Heavy Industries KXZ Series Technical Manual page 67

(2) Troubleshooting
Error code
None
Remote control:
1. Applicable model
All models
2. Error detection method
. Condition of error displayed
4. Presumable cause
• Poor compression of
compressor
• Expansion valve operation
anomaly
Note:
LED Green Red
Keeps flashing Stays OFF
Indoor
Keeps flashing Stays OFF
Outdoor
5. Troubleshooting
Diagnosis
Check the indoor fan operation.
Check the temperature difference between
return and suction air of indoor unit.
Is the
temperature difference
between return and
suction air 10-20°C at
cooling?
NO
Is the compressor
operating?
YES
Is the
compressor rotation
speed low?
YES
Check following operation control function.
. Control for determine compressor rotation speed
. Protective control by controlling compressor
rotation speed
Which control is appropriate to this phenomenon.
Is the
operating conditions of
indoor/outdoor unit
under rated condition?
NO
The unit is operating normally, but is operating
under the protective control of compressor or
other respective components.

–
Content
Operates but does not cool
Does the
YES heat load increase after
installation?
YES
Mistake in model selection.
Calculate heat load once more.
NO
" WAIT "
message is displayed [for
3 seconds] when performing
YES
cooling, dehumidifying or heating
operation from remote
control?
NO
YES
Note (1) Outdoor: 35ºC
Indoor : 27ºCDB/19ºCWB
–
'15 • KX-T-235
Countermeasure
It is normal.
(This unit is designed to
start in the soft start mode
by detecting the compressor
under-dome temperature
NO
when it restart after power
reset.)
It is necessary to replace to
higher capacity unit or to
install additional unit.
Compressor refrigerant oil
protective control at starting
is activated.
For the contents of control, refer
to the compressor start control.
Compressor may be stopped
by the error detection control.
NO
For the contents of control,
refer to anomalous stop
control by controlling
compressor rotation speed
of microcomputer control
function.
Check the followings.
• Minor clogging of filter
• Minor fouling of heat exchanger
• Minor short-circuit of airflow
• Slightly insufficient or excessive
refrigerant amount
• Poor compression of compressor
Check suspicious points
considering appropriate
operation control.
Check the followings for
reference.
• Severe clogging of filter
• Severe clogging of heat
exchanger
• Severe short-circuit of
airflow
• Severely insufficient or
excessive refrigerant
amount
• Under protective control of
compressor
• Indoor unit fan tap setting
• Valid setting of silent mode