Air conditioning nitrogen decay pressure test

Nitrogen pressure decay test for air conditioning

 

Yes I did retake 5 times that was the best every time the green light changes all the cars came. Vary noisy and windy in going to get a lapel mic to improve audio.

 

1: The advantage you don’t have to use refrigerant to do a leak test . So you don’t waste materials and you don’t waste time having to go through the recovery process to reclaim your refrigerant time and materials is money Lost.
2: Second advantage after a very expensive and time-consuming repair like replacing evaporator that takes roughly 7 hours of labor to replace . You use dry nitrogen at 150 psi then you switch your gauges over to nitrogen decay test . You can measure leaks down to 1/10 of one psi what you can never read on a set of gauges over a period of hours this would be something you would perform in your shop overnight to confirm your test will hold refrigerant in your system before performing a recharge of refrigerant .
3: at the same time well you’re going through the process of bleeding out your nitrogen from make successful test you then put your vacuum pump on bring down the vacuum to roughly 500 µm and then re-pressurized with nitrogen repeating this procedure a total of three times . It’s called (triple vac and purge ) it’s a procedures that has been performed on air conditioning for decades those with formal education in air-conditioning and refrigeration it’s one of the first things you learn in your first semesters of class when you take a two year bachelors degree or associate of science degree in HVAC. This procedure rapidly reduces any moisture that has been exposed into the pipe as they were left disconnected and atmosphere has entered saturating the ester oil or PAG oils. Because moisture in the system mixed with the refrigerant makes a hydrofluoric acid that attacks aluminum and components from the inside out causing leaks at evaporator’s or condensers breaking down the oil and causing compressor failures.
4: you cannot use refrigerant to perform a high pressure test on both low and high side of AC system. Because under a static load the refrigerant pressure cannot go any higher then the temperature of the entire system because temperature and pressure are nearly one the one directly related to the pressure of the refrigerant. To achieve and maintain a refrigerant pressure of 150 psi using R134 refrigerant The entire vehicle would have to be in a desert or in a oven at 112°F otherwise add ambient lower room temperature the refrigerant pressure would continuously drop nitrogen does not suffer from this problem. And nitrogen is dirt cheap and when you’re finished with it you just vent it to the atmosphere. If somehow you were able to force 150 psi vapor R1 34 refrigerant into the system on an average day of 70°F the pressure would immediately start dropping down to roughly 70 psi to match the ambient temperature and pressure so you would not be able to find a leak using this method. This is for locating leaks that only leak at high-pressure 150 psi or greater there is many times there’s leaks that only leak and start to leak at high-pressure but do not leak at low pressure this is for those hard to find leaks. After you had a compressor burn out and you completely taken apart the entire system to flush out all the lines replace all the O-rings at 20 different fittings remove the dash replaced expansion valve you have a $3000 plus repair bill and many hours of labor tied up you would wanna know that you’re 100% satisfied before you charge the system up with refrigerant it will hold the pressure And not come back. and not come back.
5: unfortunately there is a massive lack and knowledge of education how to properly perform air conditioning service that results in many failed compressors and loss times and customers losing money from shops who do not know what they’re doing. The majority of all the repairs and redos I perform come from other mechanical shops and air-conditioning shops who previously repaired the vehicle two or three times before I’m called in to clean up their mess. 80% the majority of the repairs moisture contamination is one of the biggest problems unfortunately in the automotive field The incompetence level is extremely high 95% of the shops who just do air-conditioning do not own a micron gauge. 98% of the shops do not even know what what a micron gauge is and look at you like a stun the deer in the road with the headlights in their eyes. And even if you handed automotive technician a micron gauge in their hand to use on the air-conditioning they would just shit their pants and drool and would have to change their diaper because they don’t even know what it’s for or how to use it. Majority of automotive technicians do not even know that an air conditioning compressor should last the entire life of the vehicle so long as it’s maintained and no outside force causes damage to it like failing condenser fans or expansion valve or improper service by a dirty technician who hooks up his gauges that are filled with air tops off the system without doing a complete recovery and a complete vacuum is usually the reason why The compressor fails.