Additional Refrigerant Charge - Panasonic U-26PE1U6 Technical Data & Service Manual

4-5. 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) effi ciency 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.
1
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 suffi cient 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.)
1. Leak Test
(1) With the service valves on the outdoor unit closed,
remove the 1/4 in. fl are 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.
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.
Manifold gauge
Manifold valve
Pressure
Lo
gauge
Gas
tube
Liquid
tube
1-116
1. Specifications
Fig. 1-26
Vacuum pump
Outlet
Inlet
Fig. 1-27
Hi
Charge hose
Cylinder
valve
Nitrogen gas cylinder
(In vertical standing
position)
Open
Close
Outdoor unit
Close
Fig. 1-28