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Charge HVAC R410a as a Gas?

53K views 22 replies 7 participants last post by  yuri 
#1 · (Edited)
Hello, I have read that R410a should be added to a system as a liquid. But I have not read where there is really any issue with adding R410a as a gas to the low side service port? As long as it is added slowly, does anyone see a real problem with adding R410a to the suction service port at the compressor?
Has anyone actually tried adding R410a to the LS suction port as a gas?
 
#2 ·
Well, you can't charge to the high side. It should be obvious that the output of the compressor is going to be a higher pressure than the R-410a in the bottle at ambient temp.

I have never done R-410a yet but as I understand it you charge liquid to the low side but *slowly* as to allow it to vaporize on the way in so it doesn't slug the compressor. Liquid charging needed to preserve the mix of refrigerants in their original fractions.
 
#3 ·
Yep, you DO NOT charge it out of the bottle as a gas or it will fractionate/separate into its different components. The Pros use a charging manifold with a sightglass and we slowly flash the liquid into gas while watching the glass and then put it very carefully into the suction/low side. too fast and liquid enters and damages the compressor valves or scrolls and can wash the oil out of the compressor and other nasty things.
 
#5 ·
If the system is empty and in a deep vacuum then you charge as a liquid
thru the high side. depends on the size of the unit and ambient temp, you might be able to put in the whole charge without turning on. if the pressure equalize before the charge is correct then you switch over to low side and start the unit up.
 
#9 ·
I have read that a few have tried it and did not have a problem. I was curious if any pros on this site have tried it. Seems that if you have to carefully throttle it and watch the site glass when you add it as a liquid it would not matter because you have to be careful no matter how you add it. So adding it as a gas would require a similar level of care. So I am asking this forum if this line of thinking is correct or am I way off base?
 
#12 ·
Seems like it should be added as a gas when adding it to the low side port. After all, what you are mixing it with is gas and you are so close to the compressor why risk damaging it by adding it as a liquid? I know that conventional wisdom is to add it as a liquid but that doesnt mean I cant question it. Thats what sites like this are for. :)
 
#13 ·
Way back in the 80's, I started charging/topping off R22 systems with liquid into the suction line. Been doing so ever since. In the 90's, all these new gasses came out that have high fractionations, so been charging all of them by liquid through the suction line to top off, or do final charge adjustment. Been doing R410A the same way also.

I have never seen a reason to do it as vapor. Its slow, and if you end up with a leak in your system, and continue to have to top off, you will end up with an unknown amount of fractionation. let alone, not knowing the integrity of the refrigerant in the R410A cylinder you were using.

So no, I have never topped off, nor charged a R410A system by vapor. No reason to.
 
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#16 ·
It is not the system we are dealing with it, it is the actual bottle of R410. If you don't use it as liquid then the mixture in the bottle gets screwed up. Don't want the rest of that bottle being put in your system do you.:no:
 
#17 ·
Good comments so far. To continue the conversation, I would like to know your thoughts on r134a? It is a blend also and on the can it tells you to rotate the can every 3 to 5 seconds when adding it to the suction line. This means it is added as a liquid and gas. Any idea what makes r134a so special that you can do this and why r410a is not as special?
 
#18 · (Edited)
I don't think R134a is a blend, hence it would have no glide so can be charged as a gas. They want you to rotate the can to help ambient heat keep the stuff evaporating so it will charge at a reasonable rate. I sometimes use a saucepan of warm water to speed things along and get the last bit out.
 
#22 ·
R134A is a single compound refrigerant. That is why it can be charged as a liquid or vapor.

However, there are companies that make bootleg R134A. It is not pure R134A, and may contain explosive additives.
 
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