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2WAY VRF SYSTEM
Control Functions
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2WAY VRF SYSTEM
Control Functions
(5)
5-1.
System Oil Recovery Control
The system oil recovery control is performed by operating all the systems.
If the stopped outdoor unit exists, the unit starts operating and the system oil recovery control is performed.
Start of system oil recovery control
7. Oil Control
When one of the oil level of compressors is “0”, the system oil recovery control will start.
When the accumulated time reaches 60 minutes under the condition of oil level “1” or lower, the system oil recovery
control will start.
This timer will be cleared when the oil level “2” continues for 5 minutes.
* If any compressor oil level “2” remains in the same outdoor unit even though one compressor oil level “0” exists,
this oil recovery control is not performed.
When the system oil recovery control is once performed, it will not be resumed for 30 minutes.
*
System oil recovery control is performed.
System oil recovery is not performed.
compresso
r
compresso
r
Outdoor unit
Oil level “2” does NOT exist.
Oil level “2” exists.
Oil level
1
2
compresso
r
compresso
r
Outdoor unit
Oil level
0
1
compresso
r
compresso
r
Outdoor unit
Oil level
1
2
compresso
r
compresso
r
Outdoor unit
Oil level
0
2
7. Oil Control
2WAY VRF SYSTEM
Control Functions
7. Oil Control
For 2 minutes
Indoor units
Control time
Outdoor units
MOV
RAP valve kit
Fan
All outdoor units operate at maximum horsepower.
MOV at all indoor units operate at a fixed pulse according to the indoor unit
capacity.
All indoor units operate in Cooling mode (OFF status).
The fan speed depends on the indoor unit operation mode.
In the case of cooling mode
For 2 minutes
Indoor units
Control time
Outdoor units
MOV
RAP valve kit
Fan
All outdoor units operate at more than half horsepower.
MOV at all indoor units operate at 250 pulses.
All indoor units operate in Heating mode (ON status.)
・
As for heating thermostat ON indoor units, follow the indoor unit control system.
・
Fan and heating (thermostat OFF) operation of indoor unit will be stopped.
・
The fan speed of heating thermostat OFF Concealed Duct - High Static type
indoor unit (Type E1) is changed to LL.
In the case of heating mode
5-2.
The system oil recovery control shall be performed as the flow mentioned below.
Normal operation → System oil recovery control → Normal operation
Simplified flow of system oil recovery control
3WAY SYSTEM
Control Functions
8. Oil Control
(6) Oil Rotation Control
The oil rotation control system regularly exchanges oil among the outdoor units regardless of oil level.
Oil rotation control is performed every one hour with accumulated operation time among the connected multiple
outdoor units only.
During oil rotation control, ORVR may open in the order of priority of outdoor unit inverter compressor operation
every 5 minutes.
(7) Indoor Unit Self Oil Recovery Control
The indoor unit self oil recovery control system can only be performed by the cooling indoor units.
Divided into 8 groups in the order of indoor unit addresses and this oil recovery control is performed every
120 minutes with accumulated operation time per each group for 1 minute.
The indoor unit expansion valve is opened according to the values determined by the indoor unit capacity with
thermostat OFF.
20 pulses is opened from the pulse controlling the indoor unit expansion valve with thermostat ON.
Then, the fan speed is changed to L.
SM830237-07_北米向け2WAY_VRF.indb 29
18/06/19 18:55:34