INSTALLATION (CONTINUED)
13
AIR PURGING
Air and moisture remaining in the refrigerant system may create
adverse conditions as indicated below:
• pressure in the system rises
• operating current rises
• cooling efficiency drops
• moisture in the refrigerant circuit may freeze and block capillary
tubing
• water may lead to corrosion of parts in the refrigerant system
Therefore, the indoor unit and tubing between the indoor and
outdoor unit must be leak tested and evacuated to remove any
noncondesables and moisture from the system.
AIR PURGING WITH VACUUM PUMP (TEST
RUN)
Confirm each tube (narrow and wide tubes) between the indoor
and outdoor units has been properly connected and all wiring for
the test run has been completed. Remove the valve caps from
the wide and narrow service valves on the outdoor unit. Note that
both narrow and wide tube service valves on the outdoor unit are
kept closed at this stage (shipping position).
Leak Test
1. With the service valves on the outdoor unit remaining closed,
remove the threaded cover on the wide tube service port.
(Save for reuse.)
2. Attach a manifold valve (with pressure gauge) and dry nitro-
gen gas cylinder to this service port with charge hoses.
CAUTION:
Be sure to use a manifold valve for air purging. If it is not avail-
able, use a stop valve for this purpose. The “Hi” knob of the man-
ifold valve must always be kept closed.
3. Pressurize the system to no more than 150 P.S.I.G. with dry
nitrogen gas and close the cylinder valve when the gauge
reading reaches 150 P.S.I.G. Next, test for leaks with liquid
soap.
CAUTION:
To avoid nitrogen entering the refrigerant system in a liquid state, the top of the nitrogen gas cylinder must be higher
than its bottom when you pressurize the system. Usually, the cylinder is used in a vertical standing position.
4. Do a leak test of all joints of the tubing (both indoor and outdoor) and both wide and narrow service valves. Bubbles
indicate 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 loosening the charge hose connector at
the nitrogen cylinder. When the system pressure is reduced to normal, disconnect the hose from the cylinder.
Lo
Hi
Pressure
Gauge
Manifold Valve
Outdoor Unit
Indoor Unit
Charge Hose
Nitrogen Gas
Cylinder
(Vertical
Position)
