Filter
Top Products
65
Fig. 7-1
Fig. 7-2
7. AIR PURGING
Air and moisture in the refrigerant system may have
undesirable effects as indicated below.
● pressure in the system rises
● operating current rises
● cooling (or heating) 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 noncondensables and moisture from the
system.
■ Air Purging with a Vacuum Pump (for Test Run)
Preparation
Check that each tube (both liquid and gas 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 both the gas tube and liquid tube
service valves on the outdoor unit. Note that both liquid and
gas tube service valves on the outdoor unit are kept closed
at this stage.
Leak test
(1) Attach a manifold valve (with pressure gauges) and dry
nitrogen gas cylinder to this service port with charge
hoses.
(2) Pressurize the system to no more than
512 psig (36 kgf/cm
2
G) with dry nitrogen gas and close
the cylinder valve when the gauge reading reaches
512 psig (36 kgf/cm
2
G). Then, test for leaks with liquid
soap.
Manifold gauge
Outlet
Inlet
Vacuum pump
Manifold valve
Pressure
gauge
Lo Hi
Charge hose
Outdoor unit
Liquid
tube
Gas
tube
Nitrogen gas cylinder
(In vertical standing
position)
Close
Open
Close
Open
Cylinder
valve
Service port ø5/16"
CAUTION
CAUTION
Fig. 7-3
Use a manifold valve for air
purging. If it is not available, use
a stop valve for this purpose. The
“Hi” knob of the manifold valve
must always be kept closed.
To avoid nitrogen entering the
refrigerant system in a liquid state,
the top of the cylinder must be
higher than the bottom when you
pressurize the system. Usually,
the cylinder is used in a vertical
standing position. (Refer to the
previous page.)
07-056 Mini_ECOi_II_NA 3/19/07 2:41 PM Page 65