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Outdoor Unit
Refrigerant piping installation
(2) Vacuum
Vacuum drying should be made from the service port provided on the outdoor unit’s service valve to the vac-
uum 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 sys-
tem 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 nitro-
gen 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.
Vacuum pump
Vacuum pump
Indoor unit
Sub2 outdoor unit
Sub1 outdoor unit
Main outdoor unit
Close
Close
Close
Close
Close
Close
Close
Close
High/low pressure
common pipe
Liquide pipe
Gas pipe
High/low pressure
common pipe
Liquide pipe
Gas pipe
High/low pressure
common pipe
Liquide pipe
Gas pipe
Close
Liquid side
Gas side
Note : Always add an appropriate amount of refrigerant. (For the refrigerant additional charge)
Too much or too little refrigerant will cause trouble.
