C
Fig. 10-1
Fig. 10-2
Fig. 10-3
10. LEAK TEST, EVACUATION AND
ADDITIONAL REFRIGERANT CHARGE
● Perform an air-tightness test for this package A/C. Check
that there is no leakage from any of the connections.
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 and liquid 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.
● The refrigerant charge at the time of shipment is only
guaranteed sufficient for a tubing length of up to 100 ft.
The tubing may exceed this length, up to the maximum
permitted length; however, an additional charge is
necessary for the amount that the tubing exceeds 100 ft.
(No additional refrigerating machine oil is needed.)
10-1. Leak Test
(1) With the service valves on the outdoor unit closed,
remove the 1/4 in. flare nut and its bonnet on the gas
tube service valve. (Save for reuse.)
(2) Attach a manifold valve (with pressure gauges) and dry
nitrogen gas cylinder to this service port with charge
hoses.
