Finding AC Leak Under Vacuum
How To Find Ac Leak Under Vacuum is easy now! A/C and refrigeration systems are manufactured to run on only oil and refrigerant. Air and moisture enter a conventional system when it is installed and repaired. The elements oxygen, nitrogen, and moisture (which make up our air or atmosphere) are harmful to system performance. Degassing is removing air and other non-condensable, while dehydration is the process of removing moisture. Evacuation is term used to describe the removal of both.
The evacuation rig (hoses and fittings) will be separated from the system during the “standing pressure tests” to measure the vacuum quality if a high-quality vacuum gauge is placed with a copper line or brass connector connected directly to the core installed on the suction line.
Do 1st Stand-up Test For AC Leak Under Vacuum
Using a vacuum, increase the pressure until it reaches 1000 microns (if using large-diameter For a normal home system of up to 5 tonnes, hoses and core tools, line set and evaporator coil evacuation will take less than 15 minutes). Isolate the vacuum with core tools, allowing the pump to keep running, and record the leak rate reported by the vacuum gauge (after about a 5-minute stabilization period). The leak rate is essentially a reduction in vacuum over time, generally measured in microns per second.
Do 2nd Stand-up Test For AC Leak Under Vacuum
Allow the system to continue the evacuation operation until the vacuum level is 500 microns or less by opening the core tools. Then repeat the “standing test” to see if the leak rate has decreased after stabilizing the vacuum. If there is no leak, the second leak rate in the system should be significantly lower than the first, suggesting that the job of dehydration is progressing.
Difference Between System Leak And Moisture
System Leak To Find Ac Leak Under Vacuum
If there is any leakage in, the vacuum gauge will climb until atmospheric pressure is reached. If the system is vacuum-tight but still contains moisture, the rise will level out until the vapor pressure in the system equalizes, which normally occurs between 20,000 and 25,000 microns at 72o and 80o F. The vacuum reading will become stable at that point. (Note: if the system continues to level off at 3500-4500 microns, the moisture in the system may have frozen.) It may require an external heat source to boost the system temperature and remove the moisture.)
Moisture To Find Ac Leak Under Vacuum
A repeated evacuation combined with a nitrogen sweep will drastically minimize the amount of moisture present if the system detects moisture. Reduce the system pressure to 1000-2500 microns to do this technique. Disconnect the vacuum hose from the low side of the system with the core tools and isolate the vacuum pump. Nitrogen supplied through the core tool’s side port breaks the vacuum in the system. Purge nitrogen from the system at a pressure of 1-3 psig. From the apex to the apex, I let it vent through the open port of the core tool to achieve a vacuum equivalent to atmospheric pressure (760,000 microns).
Vacuum Finishing
Allow the vacuum pump to continue after the second standing test until the system is preferably below 200 microns. (With a good pump, you can easily achieve 50-100 microns.) Allow the vacuum rig to stand for 15 to 30 minutes after isolating it with the core tools.
The evacuation is complete if the micron level does not climb above 500 microns. If the pressure climbs above 500 psi, reopen the core tools and resume the evacuation. Shorter evaluation periods are possible with experience and a high-resolution micron gauge.
If you’re working on a fresh installation, keep the pump turned off and open (crack) the suction line service to let a little amount of refrigerant into the system, gradually putting the system under positive pressure. (Note that you are above 20,000 microns but still in negative pressure when the vacuum gauge reads “high pressure.”)
Conclusion
If there any leakage in the system, the vacuum gauge will climb until atmospheric pressure is reached. If the system is vacuum-tight but still contains moisture, the rise will level out until the vapor pressure in the system equalizes, which normally happens between 20,000 and 25,000 microns at 720 and 800 F.
