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Thread: 1500 microns
09-06-2012, 08:04 AM #1
I have a freezer that I feel like I know has a leak. HOWEVER, I put a vacuum on it yesterday and got it to 1250mics and left it on overnight and was told that it jumped up to 1550mics by a fellow employee last night. So this a.m. I come in and a certain somebody that is above me says "You left the pump blanked off all night, I came in this morning and turned the pump off, that was a waste of time! However, it held all night at 1550mics, its good enough"
I CALL BULL$#!T!!!!,
Reason number 1, it was on for 2hrs yesterday and wouldnt go below 1250. He wants to dump reefer in and walk away. I DO NOT!
What else other than a leak could I be looking at? I suggested blasting it with nitro and 22 and hitting with an electronic leak detector, he got all pissy and said I WAS BEING IMPATIENT!! LOL Douche. I am trying to get er done CORRECTLY! and not waste time.... WTF, I never argue with people untill common sense is ruled out.
Gimme something to work with boys...
09-06-2012, 08:23 AM #2
Pressurize with nitrogen, if no luck add some juice to it and use a leak detector. Make sure to check all hose connections and such. What was the reason for having the system open? New install?
09-06-2012, 08:39 AM #3
The system wasn't getting down to temp. I was TOLD that there was air in system. I am considered junior guy on this job. I got sent when system was allready being pumped down.I suggested that juice and nitro method and basically got belittled. I guess I KNOW what to do here, my main problem I think is getting a thick headed person who doesnt want a younger guy getting the job done that he was allready doing, but havin trouble with, doing what i suggest.... We did a presure test, WITHOUT juice yesterday and it held pressure for over an hour.... which is what confuses me most. How is it holding pressure, but not pulling a vacuum? we pressurized to 300psi and it didnt move at all.... I'm gonna write down what I suggest to him, make a copy, and give it to him. when we come back the boss can chew his ass not mine.
09-06-2012, 10:56 AM #4
How long did you pull on it for? Sometimes it seems like it takes forever for something that has had refrigerant in it. Valve packings are one of the best places to look in such a situation. Was the entire charge removed?
09-06-2012, 11:30 AM #5Professional Member*
- Join Date
- Apr 2004
Two points to consider:
Even if you were to attain a 500 micron vacuum, that does not mean you are absolutely leak free. The greatest pressure differential between inside your system and the ambient is only atmospheric pressure (typically 14.7 psi) which is actually ZERO on your gauges. So a vacuum test is an ineffective leak check as you are using ZERO psig to check with.
Also, your rise on the micron gauge (300 microns) leads me to believe you simply have additional moisture in the system oil. As Ryan stated, it does take quite a while, especially if the system uses a refrigerant that requires a hygroscopic (moisture attracting) oil.
I would break the vacuum with nitrogen, pressurize to slightly above 0 psig and put the vacuum pump back on it. Repeat then try for the 500 microns on the third time. Make sure your vacuum pump oil is fresh (change it while the pump is warm).
I should mention the new filter drier, which should be in place before the dehydration process begins.
09-06-2012, 11:30 AM #6Professional Member*
- Join Date
- Aug 2012
- willowick ,oh
why didnt you just turn the pump back on. you said he blanked it off. sometimes it takes a long time due to the fact there is residual refrigerant saturated in the oil from being running already.If it held at 1500,and did not slowly rise, you may not have a leak.Dont quote me though thats just my experience with issues like these.Always wanna go at least 400 tho.Once you isolate the pump from the system, your micron level will always rise some and should stop and sit at one level if there are no leaks.
09-06-2012, 03:34 PM #7
I said HE turned the pump off and disconnected it before I got there. I was saying Why the hell wouldnt he just turn it back on!
I know about the triple evac method, I even mentioned it to him before he juiced it. I was called impatient. LOL UMMMM.... He's BassAckwards.
Told the boss to only send me with techs that do things correctly from now on. He asked what I meant, I told him I'm not a rat, but that guy is a problem waiting to happen. And to ask him details about why we disagree.
Fact of the matter is, me and the tard I was working with have agreed to disagree, I wanted to leak check with electronic leak detector, w/ nitro and juice. He told me I'm retarded. I told him that he can tell store owner why the meat goes bad over next weekend. LOL. He juiced it up, probably with moisture still in system or small leak. Not my concern, just a real good "I TOLD YOU SO" coming once system starts running all jacked up again... Some people.
09-06-2012, 03:35 PM #8
I should mention, I didnt see how it worked, I left as he was juicing system. I couldnt deal with the B.S. so I had boss send me on a diff call.
09-06-2012, 03:48 PM #9Professional Member
Originally Posted by SBres22
- Join Date
- Jan 2011
09-06-2012, 03:55 PM #10
09-06-2012, 04:02 PM #11
And my name calling wasnt done on the job, where he did it, I am just here venting, well, because, thats what people do. LOL
09-06-2012, 04:25 PM #12Professional Member*
- Join Date
- Sep 2005
- North GA
The answer is probably the refrigerant in the oil... happens most of the time. One gets from 760,000 microns to somewhere in the 1000-2000 range in less than 10 minutes with a good pump and clean oil. I have gotten there in less than 5 minutes with my Appion TEZ-8. Then the refrigerant starts to boil out of the oil. Depending on lots of things (amount of dissolved refrigerant in compressor oil, quality of compressor oil, where the compressor oil is in the system, length of lineset, quality of recovery set-up, tightness of recovery set-up, vacuum pump oil, and a host more)... the last couple-a-hundred microns could take as long as an hour. How much do those last couple hundred microns matter? Good question. Experience will teach the answer... which is NOT as clear an answer as one would think.
Something to consider: What 'looks' like the 'right' way today... might not look right with a few more years experience. All of us older timers have been down that road... Oh the stories we could tell.
Better IMO to keep relationships on a positive note than blow smoke... the former will advance your career... the latter, well, may well hinder or even dismantle your career.
Nothing personal... just advise from an old guy who has been there...GA-HVAC-Tech
Galatians 2:20-21; Colossians 1: 21-22 & 26-27; 3:1-4; Romans Ch's 5-6-7-8
2 Chronicles 7:14
Quality work at a fair price with excellent customer service.
09-06-2012, 05:50 PM #13
I value your opinion. Thank you. And WHY do I value your opinion and advice? Because you , sir, had the common courtesy to EXPLAIN it. The tech that was originally on the job was having issues with the system, which is why I got sent out as a fresh set of eyes and fresh mind. Because lets face it, once you start getting aggravated, you lose your mind a little. I understand that. It just seemed that EVERY bit of advice or question I brought up, I was basically belittled for.... Which is why it seems like I may have been a little bitter in a few of these posts. I 100% KNOW that I DO NOT KNOW everything, and never will. Which is what I think the other guy has a problem accepting about himself. I will be learning new things about this trade untill my mind no longer works right, and then I can learn all the basics all over!! LOL This other guy either A.) doesnt like me to begin with, or B.) doesn't like when the bossman thinks he needs help. I think B...... maayyybe A. too!
Thank you gentlemen for your responses, and YES i will 100% let you know how this turns out!