Reusing refrigerants?

[expat]

I've come across many threads (particularly where low lp was concerned) where one of the diagnostic methods used was to weigh out the gas to check for correct charge.

Now this seems like a good idea in a "process of elimination" approach. But if that wasn't the problem then you have already started running up a bill during diagnostics for the disposal of the old gas and the price of the new charge-up.

I am actually thinking of an installation I deal with which has icing back to comp. Having checked all the obvious I am seriously tempted to weigh out into a vacuumed recovery bottle and reinject the recovered charge back into the system with a top up if this turned out to be the prob.

Any advice..?

[expat]

I would just add that I'm not looking for help with the problem I have with this particular system (not yet at least:rolleyes:) but more general advice on the methods for reusing refrigerants in the systems they were reclaimed from.

Cheers.

[Samarjit Sen]

Use fresh gas. I would not advice you to reuse the refrigerants.

[paul_h]

I've done it a few times, going to a refrig wholesaler and rented a verified clean reclaim cylinder, and using an oil-less fully purged and evacuated reclaimer.
In other words, if it's a big enough charge in the sytem to make you go that trouble, then it's fine to reuse it IMHO.
But if the refrigerant charge is right, and all your problems are due to contanimation of gasses and moisture, how will you know? The reclaim weight will be right, but the moisture an incondensibles will be returned if you just put the refrigerant back in. Depending on the amount of refrigerant I would take that gamble, which is why I've only recharged the system a few times. Greater than 6kg I may reclaim into verifeid clean system and change drier, anything less then I would recharge with virgin refrigerant

[expat]

Thanks for your replys'.

I saw in a stockists a brief case affair with a manifold, drier and an oil seperater in it, presented as a recycling kit.

This is what made me think it would be a cheap way to check the charge and inso doing eliminate or otherwise one of the possible reasons for the low LP. But I suppose you're right Paul h in as much as not being certain of the purity of the fluid would not help with the diagnostic.:o

[Brian_UK]

I suppose that even with a recycling kit you need to start thinking about the time and costs involved compared to a recharge with virgin gas.

Especially with the blends in use nowadays.

[fridg]

You might lose some oil if this is done.

If you take it out , why not put new back in ?

[chillyblue]

Hi

The other week i was working on a 25KW VRF system that has 22KG's R407C in it, i suspected a leak and reclaimed the refrigerant into a special clean reclaim reciever, supplied by HRP, the amount of gas reclaimed was 18KG's, so i was right the system was 4KG's short.
The system was pressure tested with OFN and the leak was found, a cracked Flare (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=174) nut on the exit pipe from one of the selector boxes, as you rightly said it is illegal to put refrigerant into a system which is not known to be tight!!
Now back to my original question, do i refill the system with virgin R407C, and hand my client a bill for 22KG's or do i / can i return the 18kg's from the relaim reciever back into the system and top up with a extra 4kg's of virgin R407C??(makes sense to me)

To fill the system with completely new refrigerant on a plant of that size seems an awfull waste and excess cost to my client.
If the plant was a small A/C unit with a charge of 1KG, i would'nt hesitate in changing it with new refrigerant.

Also what happens when you have a plant with 60KG's in it?? every time you have a leak (may only be a couple of KG's) do you reclaim it all and refill it with new refrigerant?? and hand the client a bill for 60KG's i can't see many people doing that!!

I quote to my client your plant lost 2KG's but here's you bill for 60KG's, i can't see me getting a very good repertation that way either:mad:

I've seen it before and i can hear it now,
Client say's " i had this company in the other day, my plant had lost 2 KG's of gas and he wanted to charge me for 60KG's, so i got someone else in and they topped up with 2KG's and its as good as gold, and cost me next to nothing. The firsat bloke must have been a right robbing B~stard

Cheers

CB

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[absrbrtek]

In your case it's a toss up as to reusing the refrigerant. Factors that come into play would be how the moisture indicater looks and did it suck air into the leak? I would run it thru driers during the recovery and recharging process.

Recovered refrigerant is returned to systems all the time. I know if I am pulling out a 250 KG to a 4000 KG charge unless it has free standing water, it is going back into the system. The customer does not want to buy new refrigerant just because I changed a compressor seal.

On larger charges if you suspect the refrigerant is contaminated, send a sample out for analysis. On most of the larger equipment we service, oil and refrigerant analysis are done on an annual basis. It gets interesting trending the refrigerants purity over the years.

Depending on the test results, various courses of action will be taken, drier changes, oil changes, etc. You can watch your acid and moisture levels decrease when following the reccomendations based on the tests.

[Lowrider]

I have read documents, can't find them at the moment, that indacate that for instance R407c can loose up to 30% for 3 times and still can be topped up without any measereable difference.

If there's water in the system or it has a leak in the discharge line and lost more than 50% I would change all the charge. But that's just my opinion!

[expat]

Interesting replies, thanks.

absrbrtek and chillyblue I get your points'.

It gets interesting trending the refrigerants purity over the years.

absrbrtek, just wondering what sorts of things you may have noticed regarding purity.

...R407c can loose up to 30% for 3 times and still can be topped up without any measereable difference.

Sandreth, I've heard this sort of thing as well.

Here's something else I heard.
Several years ago, before training I bought an a/c unit from a local supplier. I knew nothing about air conditioning but he said it was easy and explained briefly how to install it. Some time went by before I got round to installing it and I had forgotten what he told me to do at the end,... something to do with letting a little gas out before tightening the nut up:rolleyes:

So I went back to ask. "Oh no, I was wrong about that" he said. "That worked with the old gas (R22) but it won't work with the new gas because it's a mixture and one gas will escape, and you'll have no guarantee then." He had since bought a vacuum pump.;)

Of course vacuuming was the wright way to do the job, but some of these sales people seem unable to tell the truth. On top of it, just to prove a point, when he came and vacuumed the system for a very short time, if memory serves, he claimed to see a tiny rise on his manifold indicating a leak. He gave me a knowing look and asked for some spanners and before leaving told me how lucky I had been.

[absrbrtek]

Just watching the moisture levels decrease with drier and oil changes. Acid levels also decreased with drier and oil changes. If you had a low pressure machine with a leak, it would be almost garranteed the moisture levels would increase, you could almost predict it like clockwork.

absrbrtek, just wondering what sorts of things you may have noticed regarding purity.