Operates But Does Not Heat - Mitsubishi Heavy Industries FDT100VNP1VF2 Technical Manual

Error code
None
Remote control:
1. Applicable model
All models
2. Error detection method
3. Condition of error displayed
4. Presumable cause
• Faulty 4-way valve operation
• Poor compression of
compressor
• Faulty expansion valve
operation
Note: When the outdoor air temperature (TH2) is 10 ºC or lower and compressor is not operated for long time,
the unit start cooling mode up to 7 minutes at heating mode.
LED Green Red
Keeps flashing Stays OFF
Indoor
5. Troubleshooting
Diagnosis
Check the indoor unit fan operation.
Check the temperature difference
between return and supply air.
Is the
temperature difference
between return and supply air
YES
10-30˚C at
heating?
NO
Is the compressor
operating?
message is displayed (for 3 seconds) when
performing cooling, defrosting and heating
operations from the remote
YES
Is the
compressor rotation
speed low?
YES
Check which control "Determination control of
conpressor rotation speed" or "Protective control
by controlling compressor rotation speed" is
appropriate to this phenomenon.
(1)
Are the
temperature conditions
of room and outdoor air close
to the rated
conditions?
Note (1) Outdoor: 7°C, Indoor: 20°C
NO
The unit is operating normally but is
operating under the contol for protecting
compressor or other respective parts.
161
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Content

Operates but does not heat

Does the
heat load increase after
installation?
YES
Mistake in model selection.
Calculate heat load once again.
NO
" "
WAIT
YES
control.
NO
NO
YES
-
'16 • PAC-T-240
Countermeasure
It is normal.
(This unit is designed to
start in the soft start mode
by detecting the under
dome temperature of
NO
compressor when it restart
after power reset.
It is necessary to replace to
higher capacity one or to
install additional unit.
Compressor refrigerant oil
protection control at starting
is activated.
Compressor may be
stopped by the error
detection control.
For the contents of control,
refer to anomalous stop
control by controlling
compressor rotation speed
of microcomputor control
functions.
Inspect the followings.
• Minor clogging of filter
• Minor clogging of heat
exchanger
• Minor short-circuit
• Minor shortage of
refrigerant amount
• Poor compression of
compressor
Considering appropriate
operation control, check
suspicious points.
Inspect the followings for
reference.
• Major clogging of filter
• Major clogging of heat
exchanger
• Major short-circuit
• Major shortage of
refrigerant amount
• Compressor protection ON
• Indoor fan tap