Panasonic R410A service manual Specifications, Manifold gauge Fig. Vacuum pump, Leak Test

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) 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

1. Specifications

Manifold gauge

Fig. 1-122

Vacuum pump

Outlet

Inlet

Fig. 1-123

Manifold valve

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.

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.

Pressure gauge

Gas tube

Liquid tube

Lo Hi

Charge hose

Cylinder valve

Nitrogen gas cylinder (In vertical standing position)

Open

Close

Outdoor unit

Close

Fig. 1-124

1-122