Fujitsu AirStage AB12, Service Manual

Page: 118 / 199

Short Resistance
Indoor
Remote
controller
PCB LED
1 to 6
LED display
Remarks
circuit
unit
Indoor
unit Outdoor
unit
– 118–
LCD
Body
LED
Symptom that
can occur other
than title
Check method
(Error state check method)
Cause
measurement
Indoor
unit
Indoor
unit 3
Normal
display Normal
display Normal
display
Indoor unit
makes an
abnormal
sound.
Installed piping not suitable.
Liquid piping diameter incorrect.
Check the indoor unit capacity
and piping diameter. When the diameter is large,
a refrigerant rushing sound is
generated and when
the diameter is small,
capacity will be insufficient.
Outdoor unit refrigerant
switching 4-way valve
(4WV1) faulty. (Cooling/heating
pump type only) 28 dia. pipe temperature
corresponding to 4WV1
energized state (cooling :
de-energized, heating :
energized (AC220V)) is
abnormal (cooling : cold,
heating : hot).
Four-way valve coil
resistance : 1200~1500
Outdoor heat exchange
switching 4-way valve (4WV2,
4WV3, 4WV4) or solenoid valve
(SV7, SV8) faulty. Check the heat exchange
operation capacity at the LED
on the outdoor control PCB.
Corresponding heat exchange
4-way valve and solenoid valve
energized state (AC220V) is
abnormal. (Refer to section
5-2 of the service manual for
the energized states.)
When a 4-way valve or solenoid
valve is faulty, the high pressure
will rise during the cooling
operation and the low pressure
will fall during the heating
operation.
Coil resistance : 1200~1500
Overall
refrigerant
pressure rises
(in particular,
high pressure
rises
abnormally)
or falls.
Refrigerant additional charge
is unsuitable.
Check the Model No., liquid
piping diameter, length of
the connected indoor unit, and
the additional charge amount. When gas is insufficient,
the capacity drops and when
gas is excessive, the high
pressure rises abnormally.
Error display
(Outdoor
unit error) Error display
(Communi-
cation error)
Error display
(Outdoor
unit error)
Normal after power reset.
Indoor~outdoor unit
communication line faulty. When communication terminal
board (Trans Mission) terminals
1-2 of one indoor unit was
shorted, the resistance across
communication terminal board
(Trans Mission) terminals 1-2 of
all the indoor units does not
indicate a value near zero.
Normal
display
Error display
(High
pressure
error) Normal
display
Indoor unit system type selector
switch (DIP SW7-1, 7-2) setting
error.
Set to cooling/heating pump
type/cooling only type with heat
recovery type piping. Cool air or warm air not
discharged from indoor unit
during both the cooling and
heating operations.
Refer to the service manual
(section 4-4 "Outdoor Unit") for
the switches.
Normal
display Normal
display or
error display
(Compressor
error)
Normal
display
Insufficient gas (serious)
When the number of operating
indoor units was changed,
the indoor unit discharge
temperature does not become
low (does not become high).
For serious gas insufficiency,
the high pressure always drops
and the low pressure always
rises during all operations.
Error display
(Thermistor
error) Error display
(Indoor unit
error) Error display
(Thermistor
error) Indoor fan unit
not operating.
Indoor thermistor faulty.
Measure the thermistor
resistance and compare it to
the ambient temperature.
Normal
display
Error display
(High
pressure
error) Normal
display RB unit solenoid valve wiring
faulty. When a relevant indoor unit
performs the heating operation,
the high pressure becomes high
and warm air is not discharged
from the indoor unit.
Solenoid valve wiring
corresponding to the connection
piping must not be connected to
the same indoor unit.
(Trouble occurs especially easily
with the UTF-Y90A1A.)
Resistance
measurement
Refer to the service manual
(section 8-5-1) for the
temperature and thermistor
resistance relationship.
When a thermistor is shorted
or open.