Fujitsu AirStage AB12, Service Manual

Page: 121 / 199

3. Abnormal sound is heard from the indoor unit.
PCB LED
1 to 6
LCD
LED display
Remarks Cause
Remote
controller Indoor
unit Outdoor
unit
– 121–
Normal
display Normal
display Normal
display
RB unit solenoid valve faulty.
SVb1, 2 solenoid valve faulty.
When heating operation starts,
a voltage (AC220V) is applied to
indoor unit control PCB CN6
(across terminals 3-4), but 3
minutes later a loud refrigerant
rushing sound is generated from
the RB unit.
Coil resistance : 1200~1500
Indoor electronic expansion
valve opening faulty. Coil resistance (red-white,
red-orange, brown-blue,
brown-yellow) : 100~200
Indoor unit
other than the
relevant indoor
unit does not
perform cooling.
Indoor electronic expansion
valve opening faulty.
Fully open (open excessively)
Cooling operations performed. The area (heat exchanger) near
the air diffuser is not cooled even
after several minutes have
elapsed since the relevant
indoor unit was stopped.
(Gas pipe is cold.)
When the electronic expansion
valve is open excessively, other
indoor units may not operate at
full capacity or a loud refrigerant
rushing sound may be generated.
Indoor unit
other than the
relevant indoor
unit does not
perform cooling.
Indoor unit heat
exchanger icing. Indoor unit electronic expansion
valve opening faulty.
Fully open (open excessively)
Cooling stopped The area (heat exchanger) near
the air diffuser of the stopped
relevant indoor unit is cold.
(Gas pipe is cold.) When the electronic expansion
valve opens, the indoor heat
exchanger may ice while
stopped and water leakage or
other trouble may occur.
Indoor unit
other than
relevant indoor
unit does not
perform heating.
Indoor unit electronic expansion
valve opening faulty.
Full open (open excessively)
Heating operation When the relevant indoor unit
performs the heating operation
or another indoor unit performs
the heating operation, the indoor
unit discharge temperature does
not become high and the high
pressure becomes low.
Indoor unit electronic expansion
valve opening faulty.
Full open (open excessively)
Heating stopped. When the relevant indoor unit or
another indoor unit performs the
heating operation, the indoor unit
discharge temperature does not
become high and the high
pressure become low.
System does
not cool/heat
Outdoor cool/heat switching
4-way valve (4WV1) faulty.
(Cooling/heating pump type only)
28 dia. gas piping temperature
corresponding to 4WV1
energized state(cooling,
de-energized, heating,
energized(AC220V) is abnormal
(cooling : cold, heating : hot).
4-way valve coil resistance
: 1200~1500
Outdoor heat exchanger
switching 4-way valve (4WV2,
4WV3, 4WV4) or solenoid valve
(SV7, SV8) faulty.
Check the heat exchange
operation capacity at the outdoor
control PCB LED.
The energized state (AC220V)
of the heat exchange 4-way valve
and solenoid valve corresponding
to it is abnormal. (Separate
sheet 1) When a 4-way valve or solenoid
valve is faulty, the high pressure
rises during the cooling operation
and the low pressure drops
during the heating operation.
Coil resistance : 1200~1500
Installed piping is unsuitable.
Liquid piping diameter is
incorrect. Check the indoor unit capacity
and pipe diameter.
When the diameter is large, a
refrigerant rushing sound will be
generated and when the
diameter is small, capacity will
be insufficient.
Check method
(Error state check method)
Symptom that
can occur other
than title
Body
LED