50
Outdoor Unit
Pipe connections between indoor and outdoor unit
(2) Vacuum
Vacuum drying should be made from the service port provided on the outdoor unitʼs service valve to the
vacuum pump commonly used for liquid pipe, gas pipe and high/low pressure common pipe. (Make
Vacuum from liquid pipe, gas pipe and high/low pressure common pipe with the service valve closed.)
* Never perform air purging using refrigerant.
• Vacuum drying: Use a vacuum pump that can evacuate to -100.7kPa (5 Torr, -755mmHg).
1. Evacuate the system from the liquid and gas pipes with a vacuum pump for over 2 hrs and bring the
system to -100.7kPa.
After maintaining system under that condition for over 1 hr, confirm the vacuum gauge rises. The system
may contain moisture or leak.
2. Following should be executed if there is a possibility of moisture remaining inside the pipe.
(Rainwater may enter the pipe during work in the rainy season or over a long period of time)
After evacuating the system for 2 hrs, give pressure to the system to 0.05MPa(vacuum break) with
nitrogen gas and then evacuate it again with the vacuum pump for 1hr to -100.7kPa(vacuum drying). If
the system cannot be evacuated to -100.7kPa within 2 hrs, repeat the steps of vacuum break and its
drying.
Finally, check if the vacuum gauge does not rise or not, after maintaining the system in vacuum for 1 hr.
WARNING
When installing and moving the air conditioner to another site, recharge after perfect evacuation.
- If a different refrigerant or air is mixed with the original refrigerant, the refrigerant cycle may malfunction and
the unit may be damaged.
Scale
Use a graviometer. (One that can measure
down to 0.1kg). If you are unable to prepare
such a high-precision gravimeter you may
use a charge cylinder.
Indoor unit
Slave 1 outdoor unit
Master outdoor unit
High/low pressure
common pipe
Liquide pipe
Gas pipe
High/low pressure
common pipe
Liquide pipe
Gas pipe
Liquid side
Gas side
Close
Close
Close
Close
Close
Close
Vacuum
pump
Vacuum
pump
Note : Always add an appropriate amount of refrigerant. (For the refrigerant additional charge)
Too much or too little refrigerant will cause trouble.
To use the Vacuum Mode
(If the Vacuum mode is set, all valves of Indoor units and Outdoor units will be opened.)
