10-24-2011, 03:35 PM | #1 |
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purge ac system
I have my Old Air ac ready to go, (now that winter's coming, of course,) but I need to purge it before charging with 134, and none of the auto parts shops around here rent vacuum pumps. Any creative suggestions?
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10-24-2011, 04:27 PM | #2 |
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Re: purge ac system
there is no shortcut to purging the air. if you dont evacuate all the air , you will only create more problems.
check at a local AC supply house and ask who does side work. one of the guys should be able to come by for 1/2 hour for a couple of beers. I am an AC- refrigeration guy by trade too far away to help |
10-24-2011, 04:50 PM | #3 |
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Re: purge ac system
I think harbor freight sells them.
You might see if Old air has pumps that you send back to them, ya never know. |
10-24-2011, 08:07 PM | #4 |
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Re: purge ac system
Just take it to a shop and have them pull a vacuum and charge the system.
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10-24-2011, 09:46 PM | #5 |
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Re: purge ac system
I picked up an orificed vacuum generator today. It'll take a while to pull it down, but I'm in no hurry.
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10-25-2011, 07:54 AM | #6 |
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Re: purge ac system
I bought an electric pump from Harbor Fright for under $100.
Make sure you get the vacuum down to -28" Hg. Then close off the vacuum and make sure it stays there for 30 minutes. Getting it down to -28" Hg boils all the water out of the system. Water from the air will kill your AC. Keeping a vacuum for 30 minutes proves that you have no leaks in the system. No water and no leaks = happy AC system.
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10-25-2011, 11:21 AM | #7 |
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Re: purge ac system
I bought the $19.95 vacuum generator from Harbor. We used these on automated cycle purge systems when I worked for a specialty gas systems company. The ones we built would pull 29" on 60 psi of air... but we'll have to see what the HB unit does - if it does anything! I figure for twenty bucks I'll give it a shot. If it doesn't pull, I'll take it back and buy the pump.
I'd like to cycle purge the system, but don't have a supply of dry nitrogen. Best way to remove moisture is about 60 cycles of pressurized N2/hard vacuum back and forth. Pulling straight vacuum leaves moisture in the dead legs of the system. I'm surprised the ac shops don't cycle purge. |
10-25-2011, 12:32 PM | #8 | |
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Re: purge ac system
Quote:
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10-25-2011, 02:02 PM | #9 | |
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Re: purge ac system
Quote:
If you dont own a pump or cant rent one and charge the system yourself, you should just take it to a shop and have it done. If you have to buy the pump, will you ever need it again?
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10-25-2011, 03:51 PM | #10 |
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Re: purge ac system
The $20 vg worked pretty good, but my compressor isn't up to feeding it, so I brought it back to Harbor Freight and bought a pump for $80. I don't go to shops to get any work done on my truck. I don't trust the quality of the wrenchers. Besides, this is fun. I'll use the pump and manifold to recharge my old man's S10, then craigslist it.
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10-29-2011, 08:02 PM | #11 |
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Re: purge ac system
I borrowed one from Autozone, although I had to put down the whole cost of the thing as a deposit.
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10-30-2011, 01:10 AM | #12 |
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Re: purge ac system
I wound up buying a pump from harbor freight and got it all finished up a couple days ago. I'll have to get some pics up. Blows nice and cold.
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10-30-2011, 12:20 PM | #13 | |
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Re: purge ac system
Quote:
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10-30-2011, 12:23 PM | #14 |
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Re: purge ac system
I have the 2-stage pump from HF, it works like a charm. I have used it on both R-12 and R-134 systems.
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10-30-2011, 10:45 PM | #15 |
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Re: purge ac system
I can hardly wait for summer. Just have to touch up the firewall paint, and it's all done.
Thanks to everyone who shared tips, and especially Chris, who offered to loan me his vacuum pump, (too late - but it's the thought that counts!) Great bunch of people on this forum. |
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