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Heeheeheehee!! Hoohoohoo!
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Hi everyone, this is my first thread on DIYChatroom Forum since I am a newly registered member. :biggrin2:The reason to why I had joined DIYChatroom Forum is because of questions like this one that made me worried lately and since I am not familiar with the laws in the USA because I am not in the US and I assuming that this is an international forum. I am very concern about my safety and the possibility of the explosion of either the compressor or ac coils or maybe even my refrigerant jug/tank under certain situation. I just came from HVAC Talk but cannot get any proper response :vs_cry:(I wish that I can ask a Pro on HVAC Talk). I tried to ask this question on HVAC Talk but they are very discriminatory towards us DIYs and not willing to give a basic safety advice even though, this is not really an elementary question but a question concerning safety and their philosophy is just not compatible with mine since I believe that anyone can do anything in this world especially if they do it correctly. :eek:Many of our home appliances are also dangerous such as a gas stove but we all learned on how to use it and went from novice to a pro. In Thailand, many of the so called HVAC professional technicians learned from just looking at what other technicians do and maybe they did not even spend money to attend an HVAC school or take an HVAC course. If we do it correctly then it might not be dangerous. Maybe they are concern with legality or fearing for being charge with lawsuit if someone got hurt. (Of course, I do admit that there were non well trained DIYs that got killed in an explosion but this is something that can also happen to a professional based on the news that I had watched) :biggrin2:

Before I will start, I just wanted to say that I am aware that using refrigerant instead of nitrogen for leak test is illegal in many states or countries in this world so I don't encourage anyone doing this but I am still curious to ask about it or like whether it is still possible in the terms of safety but not legally that we can still use refrigerant/freon for leak test instead of using nitrogen without exploding and risking to get killed. From what I know is that in the past, many people used to go with this old school method like charging ac unit with refrigerant like R22 (could deplete ozone layer and very toxic) for leak test but I still hear from many of the people in this third world country especially the DIYs who still use this method for leak test. Maybe it's because it is still not illegal in this country. Strangely, I managed to also buy an R22 jug from a store without any problem or without certification of HVAC. All of my AC units use R22 since most of them are quite old except for the refrigerators that use R134A. (Not sure if I can replace R22 with R458A (Bluon, futuristic refrigerant, non flammable and non depleting to ozone) or R404A or R407c for my R22 AC units since I don't know if my compressors use compatible POE oil or not) :vs_cool:

So my question is: is it safe to charge refrigerant for leak test while the pressure is at 0 PSI but not at -30 PSI in case if there is a severe leak and it is impossible to use vacuum pump to pull down the vacuum down to -30 psi without risking to explode everything??? At zero psi, it means that there is still air or oxygen inside the ac coils. My first guess is that it is impossible for the air bubble to still be trap inside the ac system especially when there is a severe leak holes and the refrigerant was being charged into the system since refrigerant is heavier than air. I think that the effect might be the same like when we connect the gas hose to the refrigerant jug and we had to bleed the air out (of course it would not explode if it goes into contact with oxygen). Is it also fine if I charge it to 150 psi max (low pressure side) for leak test with R22 or with something like R32 (for Daikin R32 units)/R410A???? What scares me more is the mild flammable refrigerant like R32 and the lower flammable R410A and the presence of refrigerant oil inside the ac system... What is going to happen if I use one of these refrigerants for leak test at zero psi when there is still air inside the ac coils under severe leakage????? Would it explode??? I heard about explosion due to compressed air or compressed pure oxygen being used instead of nitrogen gas. I also hear about if compressed oxygen goes into contact with oil then it can still explode without ignition or spark. Is it as dangerous as compressed air or compressed pure oxygen???? (Assuming that there will no idiots nearby who would light up a cigarette or light up a brazing torch during this procedure and of course, I would not even dare to turn on the ac unit and the main circuit would be turn off) :vs_worry: :vs_shocked:

(I heard about technicians mixing nitrogen gas with trace gas such as R22 for leak detector to work but I don't know about using 100% refrigerant instead of nitrogen for the leak test especially the flammable ones like R32 and R410A)

Sorry for my ignorance since I am just a novice DIY guy..... :biggrin2:
 

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Pure refrigerant will not work for a pressure leak test. It’s simply not doable.
Use nitrogen.
Use nitrogen with a refrigerant trace when using an electronic detector.
 

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Your post was very hard to read. A lot of irrelevant stuff. Definitely needed better formatting.

R410A doesn't support combustion under atmospheric conditions. It will burn in the presence of a flame, but will extinguish when that flame is removed.

As Roughneck said, refrigerant cannot be used as a leak test, unless you using a "sniffer" device. You use nitrogen and wait some time to see if the pressure drops. Nitrogen doesn't change its characteristics very much at the conditions we work with, which makes it reliable. Refrigerant does change, which makes it useless for pressure testing.

You should recover any refrigerant instead of releasing it, however it's probably not law where you are.

If you have any questions with your appliances, ask about them separately or things will get confusing.

And finally, welcome to the community!

Cheers!
 

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Yes, you can put just refrigerant in and use soap or electronic detector to check for leaks.



Putting nitrogen in in also to get the pressure up higher usually works best though.
 

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Yes, you can put just refrigerant in and use soap or electronic detector to check for leaks.

Putting nitrogen in in also to get the pressure up higher usually works best though.
...unless you using a "sniffer" device. ...
I forgot to add soap to that. It isn't as efficient, and you can miss the smaller leaks. (especially in coils.) It's not a great idea to add it when you don't have any in there to begin with. Other then the environmental effects, it gets expensive real quick. It still doesn't work as a pressure test.

If the refrigerant is mixed with nitrogen or air, it will be useless. There's a method to separate them, but it takes quite some time and a recovery bottle.

Cheers!
 

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Heeheeheehee!! Hoohoohoo!
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Discussion Starter #6 (Edited)
Thank you very much to all of you for reading and replying to my thread. I really appreciate that.:vs_bananasplit: :vs_clap:


The reason to why I was asking this question that might still sound kinda noobish is because some of other DIYs are asking me this same question but I don't know how to answer them and I will not dare to answer them because if someone get killed due to explosion or doing something stupid then I will not hold any responsibility for their death but at the same time, I feel like a noob too in not being able to answer this question and it would be a shame for me not to even know about this so this is why I had created this thread. :eek:

However, yesterday night, I think that I had accidentally found answers to my questions simply because I was reading comments from another forum about some people using propane based refrigerant for their ac units and for their vehicles and it sparked a flame discussion between the certified EPA and HVAC technicians which was good for me because it revealed many answers or mysteries about the dangers of refrigerants that we are using including the non flammable R22. This is also a funny flame discussion between the techs that I would like to share and it really entertained me yesterday night. :devil3: I will post a link of this flame discussion later below this post since I need at least 1 post to post links according to this forum.

What I had learned from what I think to be an old man who's been working in HVAC industry for over 24 years is that even R22 can still be explosive or combustible under high pressure condition while being mixed with air without any heat or spark. It is a type of methane gas. Nitrogen is not combustible but R22 is still combustible despite its classification as being non flammable A1. It will not burn in atmospheric pressure but it can still burn or explode in high pressure in the presence of air and perhaps even oil. But what he meant by that is if it is being compressed in a well-self contained environment such as a tank or non leaking ac lines then it might still explode. What I still don't know is that what if the ac has severe leaks and not a well-self-contained environment and how much pressure would it take to cause an explosion? Would we still be able to compress the refrigerant in a severely leaked system with air without risking the explosion? Or would the Air automatically bleed out from the bigger leak holes (not the pinholes or microleak holes). I bet that the pressure would build up but I don't know if it could trigger an explosion like lets say if we charge it at only 30 psi or 50 psi for leak test (vehicle's wheel tires are at max 45 psi to 50 psi, just to give an idea). (I would not dare to put it up to 150 psi under this circumstance for the low pressure side) I was also wondering if using vacuum pump alone is enough to check for the leaks like by hearing the noise it makes at the leak holes but without soap bubble or dishwasher detergen. Is this possible especially with a severe leak??? :sick:

At the end, I would like to say that, yes it is illegal to charge the R22 refrigerant in the leaking AC system without first repairing the leaks (based on EPA requirements). Nitrogen is the best gas to use because it is non reactive and non combustible when compressing it with air since air is already made up of 78% of nitrogen and having a little amount of combustible gas such as oxygen at 21%. The biggest problem is that in this country many DIYs do not even have a nitrogen cylinder for doing a leak test but they still wanted to do it. :zorro:


Sorry for another long post but I just love to type with my keyboard and discuss.. :biggrin2:
 

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Discussion Starter #8 (Edited)
Your post was very hard to read. A lot of irrelevant stuff. Definitely needed better formatting.

R410A doesn't support combustion under atmospheric conditions. It will burn in the presence of a flame, but will extinguish when that flame is removed.

As Roughneck said, refrigerant cannot be used as a leak test, unless you using a "sniffer" device. You use nitrogen and wait some time to see if the pressure drops. Nitrogen doesn't change its characteristics very much at the conditions we work with, which makes it reliable. Refrigerant does change, which makes it useless for pressure testing.

You should recover any refrigerant instead of releasing it, however it's probably not law where you are.

If you have any questions with your appliances, ask about them separately or things will get confusing.

And finally, welcome to the community!

Cheers!

Yes but R410a is still a combustible refrigerant especially under high pressure and when mixed with air. It can still cause explosion. Even worse is that it already contain flammable R32 but it also contain an ammonia type R125 which suppress the flammability of R32. Also non flammable R22 can cause an explosion under that condition but I don't know the max pressure to trigger an explosion. I just hope that severe leak holes will bleed the air out rather than making it being compressed together with R22. When I open the valve, the pressure is going to build up anyway but I don't know what is inside the coils or I don't know if the air is still present inside the ac system. If it does then that is very scary.


For refrigerant recovery process, I am planning to buy a recovery tank and a recovery machine which are quite expensive too. I had seen some techs managed to recover the refrigerant from high side or liquid line without recovery machine.


What happens when refrigerant change its characteristics. What do you mean by that???
 

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Your worried too much.
 
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Heeheeheehee!! Hoohoohoo!
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Discussion Starter #10 (Edited)
Your worried too much.

Well, I had seen news of ac professionals who got their limbs torn apart in an explosion. For instance, I saw a pro welder from Texas who got killed in a blast. I also had seen many pros in third world countries who died in an explosion involving charging a refrigerator and ac units. Maybe it is also because there are many counterfeit Chinese refrigerants like the fake R22 (R22A) which is a mixture of R40 and R22 including the fake R134A blended with R40 which is very reactive to aluminium fridge coils so it is very dangerous . Also countries like India still uses the propane based like R290, R600 since they are cheaper. Anyway, I am just a DIY and after seeing all these scary news then maybe I got good reason to be worried? :eek:
 

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Well, I had seen news of ac professionals who got their limbs torn apart in an explosion. For instance, I saw a pro welder from Texas who got killed in a blast. I also had seen many pros in third world countries who died in an explosion involving charging a refrigerator and ac units. Maybe it is also because there are many counterfeit Chinese refrigerants like the fake R22 (R22A) which is a mixture of R40 and R22 including the fake R134A blended with R40 which is very reactive to aluminium fridge coils so it is very dangerous . Also countries like India still uses the propane based like R290, R600 since they are cheaper. Anyway, I am just a DIY and after seeing all these scary news then maybe I got good reason to be worried? :eek:

Probably some of those explosions were caused by them having an open flame near by at the same time.


Yes R290/LP, and or R600/Butane can explode under the right conditions, and carelessness.



So are you going to be using propane or butane while your pressure testing/leak checking.
 

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Heeheeheehee!! Hoohoohoo!
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Discussion Starter #12
So are you going to be using propane or butane while your pressure testing/leak checking.

LOL! That is the first thing for me to avoid. Just by looking at the propane tanks, that is enough to scare me... (even though, I still have them outside my kitchen for the gas stove) :vs_laugh:
 

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Like beenthere said, you're worrying a bit too much. Gasoline is quite flammable, but most cars do not catch fire on a regular basis. It's actually quite safe.

For the conditions for R410A to explode, you'd have to be trying go cause it go go boom. Neither R22 or R410 or R134a will burn readily, and you'd have to be seriously trying to get it just to support a flame. It's really a not a concern.

Over filling tanks can be dangerous though. Especially if you leave those tanks in the hot sun. (or a car in the sun.) If you never over fill the tank, store it up right, you will be safe. If you never mix refrigerants, and buy only from stores that are reputable, you'll have very little to worry about.

Asking is the first sign of the desire to learn. Never be shy about it. Most accidents are caused by people who didn't want to ask the important questions.

Cheers!
 

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Discussion Starter #14 (Edited)
Updated:


I think that this procedure could still be done safely especially if we reach what is called Absolute Vacuum which is not definitely at -30 PSIG but at -14.69 psig or at zero psia which is the absence of atmospheric pressure (14.69 psia with Absolute Pressure Gauge and not AC manifold gauge). Air is already absent at negative 14.69 psig so if it is impossible to achieve -30 psig with the vacuum pump due to severe leak then we can quickly charge it with refrigerant before the gauge handle goes above negative 14.69 psig after using the vacuum pump. The time depends on the velocity of the leak and the handle will rise up to zero psig again so this tricky procedure must be done very fast. This is a race against time of course. When charging the handle must always be below 14.69 psig to ensure the safety but of course this is not a perfect vacuum by industrial standard since there is still mercury level like moisture or dust but under this scenario of severe leak it is also unlikely to go below 500 microns.


The reason to why I am posting this is because I also wanted to educate the viewers who is viewing this thread but might not have the chance to view the other newer thread that I just made which is based on the same safety concern. I was having a similar discussion on another thread that I made about at what pressure is considered to be an absolute vacuum with no air so we can safely charge in the refrigerant and avoid explosion. The thread is "Difference between -20 psi vacuum and -30 vacuum". Check it out...


Thanks everyone again for replying and thanks to the viewers out there for reading... I think that it is time to move on to other threads....
 

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Updated:


I think that this procedure could still be done safely especially if we reach what is called Absolute Vacuum which is not definitely at -30 PSIG but at -14.69 psig or at zero psia which is the absence of atmospheric pressure (14.69 psia with Absolute Pressure Gauge and not AC manifold gauge). Air is already absent at negative 14.69 psig so if it is impossible to achieve -30 psig with the vacuum pump due to severe leak then we can quickly charge it with refrigerant before the gauge handle goes above negative 14.69 psig after using the vacuum pump. The time depends on the velocity of the leak and the handle will rise up to zero psig again so this tricky procedure must be done very fast. This is a race against time of course. When charging the handle must always be below 14.69 psig to ensure the safety but of course this is not a perfect vacuum by industrial standard since there is still mercury level like moisture or dust but under this scenario of severe leak it is also unlikely to go below 500 microns.


The reason to why I am posting this is because I also wanted to educate the viewers who is viewing this thread but might not have the chance to view the other newer thread that I just made which is based on the same safety concern. I was having a similar discussion on another thread that I made about at what pressure is considered to be an absolute vacuum with no air so we can safely charge in the refrigerant and avoid explosion. The thread is "Difference between -20 psi vacuum and -30 vacuum". Check it out...


Thanks everyone again for replying and thanks to the viewers out there for reading... I think that it is time to move on to other threads....

You can charge R22 into a system that hasn't had a vacuum pulled on it, and is full of air. And it won't explode when charged or ran. Won't work, but won't explode either.
 

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Discussion Starter #16
You can charge R22 into a system that hasn't had a vacuum pulled on it, and is full of air. And it won't explode when charged or ran. Won't work, but won't explode either.

??????????????????



Huh? What????



Oh really?? Because according to MSDS and National Refrigerants, it could at certain high pressure but I don't know what is the max pressure to trigger the explosion. Maybe it is because the amount of oxygen or air is just not enough in the AC system to cause that to happen perhaps...


Well, that is very interesting. Thanks for sharing that.
 

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??????????????????



Huh? What????



Oh really?? Because according to MSDS and National Refrigerants, it could at certain high pressure but I don't know what is the max pressure to trigger the explosion. Maybe it is because the amount of oxygen or air is just not enough in the AC system to cause that to happen perhaps...


Well, that is very interesting. Thanks for sharing that.

The oxygen concentration would have to be very high.
 
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??????????????????



Huh? What????



Oh really?? Because according to MSDS and National Refrigerants, it could at certain high pressure but I don't know what is the max pressure to trigger the explosion. Maybe it is because the amount of oxygen or air is just not enough in the AC system to cause that to happen perhaps...


Well, that is very interesting. Thanks for sharing that.
National Refrigerants said:
UNUSUAL FIRE AND EXPLOSION HAZARDS: R-22 is not flammable at ambient temperatures and atmospheric pressure. However, this material will become combustible when mixed with air under pressure and exposed to strong ignition sources.
A R22 compressor cannot achieve the pressures necessary. The pressure relief plugs will blow well before then, so there is no way of achieving that pressure in a system. To top it all off, your need a "very strong ignition source" You don't have 10kV in your system, so that's also impossible. This is why the very same document says that it doesn't have a flammability limit.

Cheers!
 

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Discussion Starter #19
A R22 compressor cannot achieve the pressures necessary. The pressure relief plugs will blow well before then, so there is no way of achieving that pressure in a system. To top it all off, your need a "very strong ignition source" You don't have 10kV in your system, so that's also impossible. This is why the very same document says that it doesn't have a flammability limit.

Cheers!

Oh yes, you are right about the low temperature cap or plug on one of the coils of radiator if I'm correct. Whoops! I forgot about that but I am not sure if my old ac system has that. It is basically a safety low temperature plug/valve that cannot withstand high heat and high pressure so it will pop off if the heat is high enough which would automatically evacuate the system before it can explode. It is a safety system. For the strong ignition source, I don't know but what I know is that chemical reactions with oxygen can still cause explosion with oil even if there is no spark or ignition similar to if oil gets into contact with pressurized oxygen or compressed air then it can still explode. I heard about a technician who had to recycle a used oxygen cylinder, had used lubricant oil and a wrench to open the rusted valve to release the pressure but it had exploded and he had died instantly. That was horrible and scary but i wish that R22 would not be like the compressed air or pure O2. Anyway, thanks for reminding me about that. :biggrin2:
 

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The problem with using refrigerant for a leak test is that you can lose pressure on your gauge because of temperature change. It can go up or down the pressure in the system because of temperature. The refrigerant will react to the temperature. I've seen it go down as much as 20-30 lbs without a leak because of ambient temperatures. That's why it's always best to use nitrogen. Nitrogen or CO2 it will not change with an ambient temperature change. They have really good soap bubbles at refrigeration supply houses but if that's not available to you I also carry is the kid soap bubbles. The ones that kids get and they make huge bubbles with it is a great leak detector.

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