Air Purging; Air Purging With A Vacuum Pump (For Test Run); Preparation - Panasonic U-36LE1U6 Installation Instructions Manual

6. 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.
Use a manifold valve for air
CAUTION
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.
(2) Pressurize the system to no more than
2
512 psig (36 kgf/cm G) with dry nitrogen gas and close
the cylinder valve when the gauge reading reaches
2
512 psig (36 kgf/cm G).Then, test for leaks with liquid
soap.
To avoid nitrogen entering the
CAUTION
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.)
Manifold gauge
Fig. 6-1
Vacuum pump
Fig. 6-2
Manifold valve
Pressure
Lo
gauge
Cylinder
valve
Gas
tube
Liquid
tube
Fig. 6-3
30
Outlet
Inlet
Hi
Charge hose
Nitrogen gas cylinder
(In vertical standing
position)
Service port ø5/16"
Open
Close
Outdoor unit
Open
Close