Mitsubishi Heavy Industries KXZ Series Service Manual page 68

Error code
None
Remote control:
7-segment display: –
1. Applicable model
All models
2. Error detection method
3. Condition of error displayed
4. Presumable cause
Note:
LED Green Red
– –
Indoor
– –
Outdoor
5. Troubleshooting
Diagnosis
From previous page
[Unit] YES
Does noise/vibration
occur when the cooling/
heating operation is
performing
normally?
NO
To next page
66
–
Content
Excessive noise/vibration (2/3)
Are the pipes
contacting with the
casing?
NO
Is continuous
hissing or roaring sound
occurred?
NO
Is hissing sounds
occurred at the startup or
stopping?
NO
Is blowing
sound occurred at
the start/stop of defrost
operation during
heating mode?
NO
Is cracking noise
occurred during heating
operation?
NO
Is hissing
noise occurred
during cooling operation
or after operation
stopped?
NO
–
'14 • KX-SM-221
Countermeasure
Rearrange the piping to
YES avoid contact with the
casing.
Noise/vibration is
generated when the
refrigerant gas or liquid
YES flows through inside of
piping of air-conditioner.
It is likely to occur
particularly during cooling
or defrosting in the heating
mode. It is normal.
The noise/vibration occurs
YES
when the refrigerant starts
or stops flowing. It is
normal.
When the defrosting starts
or stops during heating
mode, the refrigerant
flow is reversed due to
switching 4-way valve.
YES
This causes a large change
in pressure which produces
a blowing sound. It may
also accompany the hissing
sound as mentioned above.
This is normal.
After the start or stop of
heating operation or during
YES
defrosting, abrupt changes
in temperature cause resin
parts to shrink or expand.
This is normal.
It is the sound produced
by the drain pump that
discharges drain from
YES indoor unit.
The pump continues to run
for 5 minutes after stopping
the cooling operation.
This is normal.
Apply the damper sealant
at the place considered
to be the sources such
as the pressure reducing
mechanism. (Expansion
valve, capillary tube, etc.)