Even a few fittings that are not assembled properly can compromise the quality of the installation. Internal restrictions can cause erosion of the piping, decreased suction gas velocity and poor oil return. Cut piping should be reamed or deburred.A good set of benders will pay for themselves in short order. The best thing to do is eliminate fittings all together. Fittings require tube cutting, cleaning, deburring, assembly, brazing, nitrogen purging, and leak testing. Tubing benders should be used to minimize the number of fittings and reduce internal restrictions.Valve cores should be removed with a vacuum rated core tool to allow nitrogen to be purged through the system and to allow the system to be valved off when ever possible during tubing installation.Tubing must be kept clean and dry through the entire installation, moisture dirt and other contaminates can compromise system operation and significantly increase the time required for evacuation.One pound of water (about 1 pint) produces about 867ft3 of water vapor at 70✯." (1) Therefore in the words of David Boyd at Appion, "Keep it clean dry and tight". "It is not practical to remove large amounts of water with a vacuum pump as boiling water produces large amounts of water vapor. When it comes to system evacuation only small amounts of moisture are practical to remove this way. When moisture (liquid) enters a system or condenses the only way it can be removed is in a vapor. Quick and deep evacuation of an air conditioner or refrigeration system simply comes down to correct practices including proper installation and assembly, keeping out the moisture during fabrication and of course the right tools hoses and gauges to measure the level of degassing and dehydration. Moisture refrigerant and mineral oils form acids that willĬause system failure due to copper plating and damage to compressorĪ vacuum gauge is used to determine the level of atmosphere (degassing and dehydration) in the system. This could result in the need for complete system Into its fundamental components, it can clog the metering device andĬontaminate line sets. Systems, (like R410a) causing premature failure of the oil. Losses associated with improper evacuation can be very high. Where high temperatures are frequent, non condensibles combined with moisture will also cause oilįailure, decreased capacity and increased compressor wear and potentialįailure. Degassing removes non condensibles whichĬause increased head pressures and increased operating cost.
Evacuation is a two step process ofĭegassing and dehydration. System has been opened to atmosphere is critical to proper operation ofĪn air conditioning system. Proper evacuation after initial installation or after service where the
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