Fujitsu AB*A12, Service Manual

Page: 68 / 322

04-06
When turning on DipSW2-2(Snow falling protection fan mode) and the outdoor unit is stopping
and Tout is below 5 , fan control enters Snow falling protection fan mode.
When the outdoor unit starts the operation or Tout is above 7 ,
fan control exits Snow falling protection fan mode.
Snow falling protection fan mode : Outdoor unit fan operates on
"Hi" mode for 1 minute in every 30 minutes.
4-3-3 Snow falling protection fan mode
EEV 1
EEV 2
Turn on outdoor unit power
Turn on outdoor unit power
EEV is controlled so that the system reaches closer to the target discharge temperature that is calculated from
high and low pressure.
< Cooling mode >
< Heating mode >
500 pulses basically.
24 hours have passed since
the last initialization,and the
outdoor unit has stopped.
Initialization conditions
Control range
operation stop refrigerant
discharge
refrigerant
storage
0 - 500 pulses
0 - 500 pulses 0 pulses 0 pulses Controlled
0 pulses 500 pulses 400 pulses
4-4 EXPANSION VALVE CONTROL
4-5 SPECIAL OPERATION
4-5-1 Oil recovery operation
(1) Purpose of the operation
The amount of refrigerant lubricant oil which has been transported to the indoor units
and the connection pipe with the refrigerant will become large as the operation time of compressor increases.
It is necessary to recover the oil back into the outdoor unit for a certain time interval
in order to prevent compressors from damaging due to lack of lubrication oil.
During the oil recovery operation, appears on the display of wired and central remote controller,
and appears on the simple remote controller.
The operation indicators (LED) of the indoor units flash slowly.
Operating compressor : 2 compressors of each slave type outdoor unit
DC inverter compressor of master type outdoor unit (at 70Hz) and 1 constant
speed compressor.
EEV Opening (Indoor/Outdoor unit): Controlled pulse (as normal operation mode).
FAN speed (Indoor/Outdoor unit) : Controlled fan speed (as normal operation mode).
Oil recovery operation time : When suction sensor temperarure(Thermistor11) of master unit
detects fall in the certain temperature, oil recovery operation is terminated.
Oil recovery operation time is a maximum of 6 minutes.
(2) Starting conditions
(3) Operation
(4) Others
Starting conditions of oil recovery operation are as follows.
Indoor EEV is gradually opened. (Oil is recovered together with refrigerant.)
Accumulated time of oil recovery operation 3(Cooling) / 8(Heating) hours
Oil recovery from the gas main pipe (Only cooling mode)
If the overheating condition is continued over 30 minutes, where the difference between compressor suction
sensor temperature and low pressure sensor temperature (Suction SH) is higher than 10degC (Normal control
if Suction SH becomes small afterward),
1
1
2
2