(4) Leak test all joints at the tubing (indoor and
outdoor) with liquid soap. Bubbles indicates a
leak. Be sure to wipe off the soap with a clean
cloth.
(5) After the system is found to be free of leaks,
relieve the nitrogen pressure by loosing the
charge hose connector at the nitrogen cylinder.
When the system pressure is reduced to
normal, disconnect the hose from the cylinder.
b) Evacuation
(1) Connect a vacuum pump with charge hose.
(Fig. 8-2)
(2) With the "Lo" knob of the manifold valve open,
run the vacuum pump. The operation time for
the vacuum pump varies with tubing length and
capacity of the pump. The following table
shows the amount of time for evacuation:
Note: The rquired time in the above table is
calculated based on the assumption that the
ideal (or target) vacuum condition is around
10 mmHg abs.
(3) With the vacuum pump still running, close the
"Lo" knob of the manifold valve. Then stop the
vacuum pump.
11
Required time for evacuation when capacity of
100 liter/h vacuum pump is used
If tubing length is
If tubing length is
less than 10 m
longer than 10 m
10 min. or more
15 min. or more
L
H
Fig. 8-2
Indoor units
Outdoor unit
Vacuum pump
Unit A
Unit B
Unit C
Manifold
valve
Unit
A
Unit
B
Unit
C
