Special Operation; Oil Recovery Operation; Pre-Heat Operation - Fujitsu Airstage VR-II Series Service Manual

2-8 SPECIAL OPERATION

2-8-1 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.
< Start condition >
Compressor accumulated operation time since last oil recovery operation exceeds 3 hours
(first time: 1 hour.)
< End condition >
3 minutes have elapsed since the compressor restart and Suction superheat "Suction temperature - Lowpressure
saturaion temperature"
Or
6 minutes have elapsed since the start
< Operation >
Actuator
All compressor operation Stop
Compressor
Keeps the operation mode
Heat Ex(4WV)
Stops
FAN
0 pls
Heat Ex EEV
Open
SV1,SV2
Others
During the oil recovery operation, the status can confirm:
- 2 wires WRC --- Press the Status button on the screen.
- 3 wires WRC and Central remote controller ---
- Simple remote controller ---
- LED indication --- Operation LED (Green) flash slowly.

2-8-2 Pre-heat operation

This pre-heat operation protects the start up failure by preventing the refrigerant from soaking into the oil in compressor.
2 pcs of belt heater installed on the compressor
The crankcase heaters are controlled by the outdoor temperature
< Control condition >
Crankcase heater ON: 30 minutes elapsed since installed compressors stopped (However, ON when power turned on)
OFF: Installed compressors operation
5
3
10 F (5 C) at all Outdoor units
Preparation process
appears on the display
35W (1 pcs)
70W (2 pcs)
On Oil recovery operatiom
All compressor start
Condensor (OFF)
Start (Target high pressure control)
480pls
Close
appears on the display
02-11
Finishing process
All compressor operation Stop
Keeps the operation mode
Stops
0 pls
Open
.