Special Operation; Oil Recovery Operation; Cooling Oil Recovery Operation; Heating Oil Recovery Operation - Fujitsu Airstage V-II Service Manual

2-5 SPECIAL OPERATION

2-5-1 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.
Simple oil recovery operation < Oil recovery from the gas main pipe > (Only cooling mode)
<
Start condition >
Suction temperature
< End condition >
Suction temperature
< Operation >
Indoor unit : Expansion valve of operating indoor unit gradually opened
Outdoor unit : Normal cooling operation

Cooling oil recovery operation

< Start condition >
Compressor accumulated operation time since last cooling oil recovery operation exceeds 3 hours (first time : 1hour)
< End condition >
30 seconds have elapsed since the start and "suction temperature - low pressure saturation temperature
at all outdoor units or 6 minutes have elapsed since the start.
< Operation >
COMPRESSOR: Performed by all INV compressors and the constant speed compressors operating up until now
INV speed varies depending on the operation state.
EEV Opening (Indoor/Outdoor unit): Controlled pulse (as normal operation mode).
FAN speed (Indoor/Outdoor unit)

Heating oil recovery operation

< Start condition >
Compressor accumulated operation time since the last heating oil recovery exceeds 8 hours (first time : 1hour)
< End condition >
After 4 minutes have elapsed
< Operation >
COMPRESSOR: Performed by all INV compressors and the constant speed compressors operating up until now
INV speed varies depending on the operation state.
EEV Opening (Indoor/Outdoor unit) : Controlled pulse (as normal operation mode)
FAN speed (Indoor/Outdoor unit)
Others
During the oil recovery operation,
and appears on the simple remote controller.
The operation indicators (LED) of the indoor units flash slowly.
low pressure saturation
low pressure saturation
: Controlled fan speed (as normal operation mode).
: Controlled fan speed (as normal operation mode)
appears on the display of wired and central remote controller,
10°C continues for 30 minutes
temperature
7°C
temperature
02-10
5deg"