Panasonic 26PSU1U6 Tech Data - Service Manual - Page 128

Leak Test, Evacuation And Additional Refrigerant Charge

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1-14. 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. 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 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.) 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. 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. 1. Specifications Manifold gauge Fig. 1-122 Vacuum pump Outlet Inlet Pressure gauge Fig. 1-123 Manifold valve Lo Hi Charge hose Cylinder valve Nitrogen gas cylinder (In vertical standing position) Gas tube Liquid tube Open Close Outdoor unit Close 1-122 Fig. 1-124

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1-122
1. Specifications
1-14. 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.)
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.
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.
Fig. 1-123
Fig. 1-122
Fig. 1-124
Manifold valve
Pressure
gauge
Lo
Hi
Charge hose
Outdoor unit
Liquid
tube
Gas
tube
Nitrogen gas cylinder
(In vertical standing
position)
Close
Close
Open
Cylinder
valve
Outlet
Inlet
Vacuum pump
Manifold gauge
1