20 Room Air Conditioner
Soap water method
1. Remove the caps from the 2-way and 3-way valves.
2. Remove the service-port cap from the 3-way valve.
3. To open the 2-way valve turn the valve stem
counterclockwise approximately 90°, wait for about
2~3 sec, and close it.
4. Apply a soap water or a liquid neutral detergent on
the indoor unit connection or outdoor unit
connections by a soft brush to check for leakage of
the connecting points of the piping.
5. If bubbles come out, the pipes have leakage
1. Connect the charge hose end described in the
preceding steps to the vacuum pump to
evacuate the tubing and indoor unit.
Confirm the "Lo" knob of the manifold valve is
open. Then, run the vacuum pump.
The operation time for evacuation varies with
tubing length and capacity of the pump. The
following table shows the time required for
evacuation.
2. When the desired vacuum is reached, close the
"Lo" knob of the manifold valve and stop the
vacuum pump.
Finishing the job
1. With a service valve wrench, turn the valve stem of
liquid side valve counter-clockwise to fully open the
valve.
2. Turn the valve stem of gas side valve counter-
clockwise to fully open the valve.
3. Loosen the charge hose connected to the gas side
service port slightly to release the pressure, then
remove the hose.
4. Replace the flare nut and its bonnet on the gas side
service port and fasten the flare nut securely with
an adjustable wrench. This process is very
important to prevent leakage from the system.
5. Replace the valve caps at both gas and liquid side
service valves and fasten them tight.
This completes air purging with a vacuum pump.
The air conditioner is now ready for test run.
Test of the leakage
Cap
Hexagonal wrench
A-UNIT
B-UNIT
C-UNIT
Gas side piping
Liquid side piping
Outdoor unit
3-way valve
(Close)
2-way valve
(Open)
2-way valve
(Open)
3-way valve
(Close)
2-way valve
(Open)
3-way valve
(Close)
Required time for evacuation when 30 gal/h vacuum
pump is used
10 min. or more
15 min. or more
If tubing length is less
than 10m (33 ft)
If tubing length is longer
than 10m (33 ft)
Indoor unit
Outdoor unit
Lo
Hi
Manifold valve
Pressure
gauge
Vacuum pump
Open
Close
Vacuum
