Haier AU282AHBEA Service Manual page 186

Air discharging method
After finishing connection of refrigerant pipe, it shall perform air tightness test.
The air tightness test adopts nitrogen tank to give pressure according to the pipe connection mode as
the following figure shown.
The gas and liquid valve are all in close state. In order to prevent the nitrogen entering the circulation
system of outdoor unit, tighten the valve rod before giving pressure (both gas and liquid valve rods).
Indoor
Completely tightened
Completely tightened
Indoor units
First step: 0.3MPa (3.0kg/cm
Second step: 1.5Mpa (15kg/cm
Third step: 3.0 MPa (30kg/cm
Check if the pressure drops
If the pressure does not drop, the unit is passed
If the pressure drops, please check the leaking point.
After pressurizing for 24 hours, each 1 C difference of ambient temperature
will result in 0.01MPa(0.1kg/cm
Checking the leaking point
From the first to third steps, if the pressure drops, check the leakage in each joint by the sense of
hearing, feeling or soap water, etc. to find the leaking point.
After confirming the leaking point, welding it again or tighten the nut tightly again.
Piping and indoor unit vacuumizing
Use vacuum pump to perform vacuumizing. It is strictly forbidden to use the refrigerant to remove
the air inside the system.
After air tightness test and discharging all the nitrogen, connect the vacuum pump as the following
figure shown.
3-way valve totally closed
(Gas side)
Outdoor
Flare part
Flare part
2-way valve totally closed
(Liquid side)
2
g) pressurize over 3 minutes.
2
g) pressurize over 3 minutes. Large leakage will be found.
2
g) pressurize about 24 hours. Little leakage will be found.
2
g) pressure change. It shall be corrected during test.
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Low pressure gauge
High pressure gauge
VLVH
Discharging valve
Dropping valve
Mainhole
Outdoor units
Meter separator
Nitrogen tank