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Kansas | I was always taught to vacuum for an hour and then wait for an hour to make sure it holds.
This is just about stupid ridiculous wasting two hours doing all of this.
What's the standard you fellas use? |
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Fruita CO | Hey Rich, I usually vac for about 20-30 min. unless I have something else to do...I've never seen any advantage to more time. Then wait to see if it drops 1" of vac. in 10 min., or if I can leave it over lunch hr., even better. Some book I read once said to do that, & it seems to work. If you have a leak, it'll show up shortly. At this altitude, 4600 ft., a vac. pump will just not pull as much as at sea level...& in this desert climate, there's not as much moisture anyway. I've seen instructions that said to vac for as long as 4 hr., & I agree that's a total waste of time. Almost seems as if you read a dozen different books, you'll get a dozen different ideas... |
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southeastern ohio | In the HVAC industry, aleast one hour on , then lock down your valves and watch for 10 minutes. A micron gauge in the system is the best setup to check for leaks or moisture. Tim |
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Hagen Brothers farms,Goodrich ND | If I KNOW that the system has been full of refrigerant so there is little chance of air / moisture having gotten in and the system has not been flushed and needs to have time to evaporate any remaining traces of flush fluid, I will vacuum for as little as 1/2 hour.
If the system has been opened and flushed, 1 hour minimum. As to waiting an hour to see if it leaks ? Depends on how frantic we are to get it fixed and back in the field. |
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Kansas | That answers my question from all 3 of you.
I thought dicking around for an hour waiting for a leak to appear was foolishness.
Thank You. Now I can get back to work.
All of ya wouldn't happen to have a miracle wand to wave or an 800 HRF planter schematic handy to copy me and email next? Mechanic said he'd be out to look at that planter in 2 hours.
That was 9:30 this morning. Still no show. |
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south texas | I was going thru the sanden compressor plant in Ft Worth one year and they put on this demo. Took a old coke bottle, put one inch of water in it and hooked up gauges. When they hit 28" vacuum the water started boiling at room temperature. Cant remember how long it took to get all the water out but is seemed to be about 15 minutes best I can recall. THat was in 1988 or so when I worked for the Yugo car co. |
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Fruita CO | Sorry, I used up my miracles last week on a broken-off ex. manifold bolt...plus, I don't know nuthin' 'bout no red planters... |
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Texas/New Mexico Stateline | Pretty much agree with the others, I hardly ever pull vacuum for more than 30 minutes. If I'm in a big hurry about 10 minutes after the vacuum stops dropping. Also I have never seen a small leak show up on the vacuum gauge. If it shows up on there it is a bad leak. Therefore if I know the system is in good shape, I don't wait to watch the gauges. Suck out the air, fill it, and get back to work. |
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Boone, Iowa | I pull the system down into a vacuum, shut off the valves on the gauges and shut the vacuum pump off. Check to see if you have less than 1" of vacuum in 10 minutes. If you do, you have not wasted 1/2 hour vacuuming down the system, just to tear apart to fix a leak. If it passes the leak test, then vacuum down the system for 20-30 minutes and charge the system. |
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MD | 15 to 20 minutes.
I let the gauges on overnight. If I lose vacuum, I got a leak.
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Fruita CO | & every once in a great while, you'll get one that will hold vac like a champ & leak when you charge it-like a split hose lining that the vacuum pulls shut... |
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ND | Exactly what I would do, 1/2 hr is plenty to pull a vacuum. |
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| I was always told you should pull it too a certain amount on the gauge. I don't recall what number now as my air operated pump won't pull as much as a real pump. My old 1135 tractor several years ago wouldn't keep freon in it long enough to run more than a couple hours. I pulled a vacuum on it a left the gauges on for about 24 hours with no change, but wouldn't hold freon. The compressor seal would only leak when the compressor was running. |
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just a tish NE of central ND | 3015DEERE - 7/1/2009 17:28
I was going thru the sanden compressor plant in Ft Worth one year and they put on this demo. Took a old coke bottle, put one inch of water in it and hooked up gauges. When they hit 28" vacuum the water started boiling at room temperature. Cant remember how long it took to get all the water out but is seemed to be about 15 minutes best I can recall. THat was in 1988 or so when I worked for the Yugo car co.
Thinking back, I seem to remember that the moisture wont boil out of the water if it is at night or morning when the temp is cooler during while repairing. I seem to remeber the temp should be a certain level to obtain boiling point at a certain amount of vacuum. I cant remember the relationship right now, but I seem to remember it must be close to room temperature. |
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How long do you leave the vacuum pump on the a.c. unit?
