57
GRFP
Fig. 8-1
Fig. 8-2
Fig. 8-3
8. 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 con-
nections.
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 refriger-
ant 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 narrow and wide tubes)
between the indoor and outdoor units has been prop-
erly connected and all wiring for the test run has been
completed. Remove the valve caps from both 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.
●
The refrigerant charge at the time of shipment is
only guaranteed sufficient for a tubing length of up
to 30 m. The tubing may exceed this length, up to
the maximum permitted length; however, an addi-
tional charge is necessary for the amount that the
tubing exceeds 30 m. (No additional refrigerating
machine oil is needed.)
8-1. Leak Test
(1) With the service valves on the outdoor unit closed,
remove the 1/4 in. flare nut and its bonnet on the
wide 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.
Manifold gauge
Outlet
Inlet
Vacuum pump
Manifold valve
Pressure
gauge
Lo
Hi
Charge hose
Outdoor unit
Narrow
tube
Wide
tube
Nitrogen gas cylinder
(In vertical standing
position)
Close
Close
Open
Cylinder
valve
CAUTION
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.
04-393 DC INV Tech p 45-63 12/13/04 11:34 AM Page 57
