Daikin GYEQ20AN Service Manual page 62

Installation Work Manual
Air tightness test and evacuation of refrigerant piping
Air tightness test and evacuation
Use tools designed specifically for use with
R410A refrigerant.
Do not open the stop valve of the outdoor unit.
Upon completion of the piping work, perform an
air tightness test by pressurizing the piping to
4.0 MPa with nitrogen gas charged from the fluid
and gas sides, as shown in Figure 1. Take care
not to exceed 4.0 MPa.
Do not use a gas different from nitrogen (oxygen
or some other explosive gas).
After pressurization, check the piping for leaks.
Particularly, the connections with the outdoor and indoor units and the portions in the vicinity of
closing valves should be thoroughly examined. You may use a soap solution to check for leaks, but
make sure that the applied soap solution is perfectly wiped off to prevent rust.
If no problems are found in the air tightness test, close valve D of the nitrogen gas cylinder, close
valves A, B, and C of the manifold gauge, and then remove the nitrogen gas side hose joint E.
Open valves A, B, and C of the manifold gauge to discharge nitrogen gas from inside the refrigerant
piping and manifold gauge.
Upon completion of the air tightness test (after discharging nitrogen gas), evacuate the piping from
the gas side using a vacuum pump, as shown in Figure 1.
Be sure to use a control valve (also called a charging valve) because air comes in when the charging
hose is removed.
The vacuum pump used must be capable of providing a negative pressure of -0.101 MPa or less.
Before using the pump, make sure that a negative pressure of -0.101 MPa or less is reached using a
vacuum gauge.
The air tightness test and evacuation tasks are important to prevent faults due to refrigerant leaks or
moisture. Make sure that they are performed.
51
7 Installing the Outdoor Unit
[Fig. 1]
Manifold gauge
Ｌ Ｈ
Ｂ Ａ
Ｃ
Ｅ
Ｄ
Nitrogen
gas or
vacuum pump
– 23 –
SiAUY361411EA
Outdoor unit side
Charging hose
Control valve
Fluid side stop valve
Gas side stop valve
Suction gas side
stop valve
Discharge gas side
stop valve
026753-01EN08
0FGHP-EN0801 DGJ002
Device Overview