Air Purging and Evacuation
Air Purging and Evacuation
Air and moisture remaining in the refrigerant system have undesirable effects as indicated below.
1.Pressure in the system rises.
2.Operating current rises.
3.Cooling(or heating) efficiency drops.
4.Moisture in the refrigerant circuit may freeze and block capillary tubing.
5.Water may lead to corrosion of parts in the refrigeration system.
Therefore, the indoor/outdoor unit and connecting tube must be checked for leak tight, and vacuumed to remove incondensi- ble gas and moisture in the system.
Checking
method
Preparation
•Check that each tube(both liquid and gas side tubes) between the indoor and outdoor units have been properly connected and all wiring for the test run has been completed. Remove the ser- vice valve caps from both the gas and the liquid side on the out- door unit. Check that both the liquid and the gas side service valves on the outdoor unit are kept closed at this stage.
Leakage test
1.Do a leakage test of all joints of the tubing(both indoor and outdoor) and both gas and liquid side service valves. Bubbles indicate a leak. Be sure to wipe off the soap with a clean cloth.
2.After the system is found to be free of leaks, relieve the nitrogen pressure by loosening the charge hose connector at the nitrogen cylinder. When the system pressure is reduced to normal, disconnect the hose from the cylinder.
• Connect the manifold valve(with pressure gauges) and dry nitro- |
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gen gas cylinder to this service port with charge hoses. |
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CAUTION: Be sure to use a manifold |
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valve for leak testing. |
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The high side manifold valve must always |
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be kept closed. | Outdoor unit |
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• Pressurize the system to no more than 150 P.S.I.G. with dry |
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nitrogen gas and close the cylinder valve when the gauge |
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reading reached 150 P.S.I.G. Next, test for leaks with liquid |
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soap. |
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CAUTION: To avoid nitrogen entering the |
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refrigerant system in a liquid state, the top | Manifold valve |
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of the cylinder must be higher than its bottom |
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Pressure |
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when you pressurize the system. Usually, the | Lo | Hi |
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gauge |
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cylinder is used in a vertical standing position. |
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| Charge hose |
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NOTICE : Leakage test shoud be done for each indoor |
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unit connection set, separately. |
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| Nitrogen gas |
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| cylinder(in vertical |
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| standing position) |
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| Service Manual | 31 |