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#21 | |
Junior Member
Trade: Chiller engineer
Join Date: Jan 2010
Posts: 11
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![]() Re: micron gaugeQuote:
If we go back to the original statement that you can never remove moisture from POE by vaccing then I still have trouble agreeing with that. On the grounds of that you could then go as far as saying that there is no point in pulling a vac ![]() Not all systems use filter driers, just look at all the splits..... |
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#22 |
Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 884
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![]() Re: micron gauge
When you install or have to open a system for service that uses POE oil.
You still want to remove as much moisture from the line set and coils as you can. So vacuuming is still an important process, to minimize the moisture left in the system/line set, and or coils as much as possible. What you don't remove. The POE will absorb. And the filter drier has that much more moisture it must remove. Mini splits generally don't have room for a drier. So its probably a matter of lack of space then any other reason that they don't have driers. Vacuuming removes moisture, nitrogen and CO2, and O2(combined, even without the moisture they're just air). You would be surprised how much moisture isn't removed from mineral oil by vacuuming. If you have the time, and curiosity. Take a baby food jar. Drill a hole in the top. Insert a fitting that you can hook your vacuum pump to. And that can be sealed to the lid. Then add 1 table spoon of water the the jar. And then add 4 times as refrigeration oil to the water, as you put in water(yes, 4 tablespoons). Put the lid on. And if you have an electronic/digital scale, weight. Then connect your vacuum pump to it. And run your pump as long as you have patience for. And yes, use your micron gauge. Look how long it takes to get a good vacuum(supposed good vacuum). After 3 hours, you will still see water under the oil. PS: No. The baby food jar will NOT implode from the vacuum. I wouldn't advise hitting it with something. But it was under a vacuum when it was bought with baby food in it.
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#23 | |||||
Junior Member
Trade: Chiller engineer
Join Date: Jan 2010
Posts: 11
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![]() Re: micron gaugeQuote:
Quote:
I could be wrong though Quote:
![]() Quote:
I can't imagine that amount of water in the system that it would form a layer under the oil, unless the oil was contaminated from the suppliers, or your vacuum pump failed during a vac and you did not have a check valve on your pump.....then it'd draw in loads of moisture.... Quote:
the pressure difference between the atmosphere and the jar would be less than 1 bar (about 14 psi) as it will be in some sort of vacuum.....another reason why using a vacuum to perform a system tightness test is highly inaccurate..... |
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#24 |
Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 884
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![]() Re: micron gauge
I use to take care of a bubble for a tennis court.
At 5"wc pressure in it. You couldn't open the handi cap emergency exit if you were in a wheel chair. And if some one helped you open it. You were blown out the door with the chair and generally fell out of the chair. The pressure had to be kept below 2"wc for that door to work right. this bubble is 150' long and 40 foot high. And help up by only 1.75"wc under normal operating conditions. So 14PSIG difference is a lot for many objects/containers.
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#25 |
Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 884
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![]() Re: micron gauge
Test/experiment number 2.
Same jar. After cleaning and drying it out. Place 5 drops of room temp water in it. Connect vacuum pump and micron gauge. Start pump and time it to see how long it takes to remove that water. It won't take long. While you set up for the above mentioned experiment. Set a container with an ounce of water in it out side. And have it covered. You want the water in it to be the same temp as the outdoor air. Hopefully its 30°F outside(it won't freeze sitting there while other test is going on). After indoor test is done. Wipe out jar. Set it outside for 5 minutes(let it get as cold as it is outside). Then add 5 drops of water from the cold container you set outside earlier. Hook up your vacuum pump and micron gauge. And time how long it takes to remove the water. And the ice you just made. At 20°F. It takes rough;y 24 hours to remove 1 of moisture(1 refrigeration drop, is 1/20 of a gram).
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#26 |
Junior Member
Trade: Apartment maintenance
Join Date: Apr 2010
Posts: 1
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![]() Re: micron gauge |
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#27 |
Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 884
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![]() Re: micron gaugeYes, you should. If I'm doing only new line sets and evap coils. I don't change it between everyone. Do one old line set, and or coil though. Change it. It makes a big difference in time.
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#28 |
Junior Member
Trade: Hvac service tech.
Join Date: Apr 2010
Posts: 2
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![]() Re: micron gauge
If we don't use one we are told to pack up our stuff and go work some place else. New refrigerant cost way to much.
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#29 |
Junior Member
Trade: Lead refrigeration supervisor
Join Date: May 2010
Posts: 1
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![]() Re: micron gauge
When doing refrigeration work you suppose to use micron gauge, I use every time you dont know how far down , I do cascade from -120f to -255f system.You have to pull these system down to 100 Micron it might take 2 day with two vacuum pump running and heat lamps. This is other way that the system is tight on leak when you have the micron gauge on the system. Pluse refrigerant is cost pre pound is high on these system 6 pound cost is 2,000 and up.Refrigerant pre pound cost for now days All my guys have their micron gauge and they all use them from system that run 1/2 pound to 600 pounds.
Last edited by Mr freeze; 05-23-2010 at 08:56 PM. |
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#30 |
Junior Member
Trade: Master HVAC Technician
Join Date: Jul 2010
Posts: 6
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![]() Re: micron gauge
Great post on the use of micron gauges. Also I love the different viewpoints. Good point about the standing vacuum test. Here how I learned it: Pull system down to 1000 microns, then break vacuum with dry N2. Do this 3 times (triple evac). Pull down to 400 and allow too sit 45 min. If the reading climbs, then holds ( ex to 1500-2000) it's moisture. If it continues a slow climb without stopping, it's a leaker.
My understanding about mini splits is that a LLD isnt used because technically there's no liqid line outside the unit (types may vary). Both lines are low pressure, thats why theres no svc fitting on the second line. The metering device is in the condenser outlet like alot of general motors cars, so what you would think would be the liquid line has refrigerant flashing inside, which I guess would make it part of the evap circuit. |
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#31 |
Junior Member
Trade: manufacturer
Join Date: Aug 2010
Posts: 1
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![]() Re: micron gauge
I design and manufacture electronic service tools for the HVAC/R industry. I will soon be going to market with a new micron gauge, and I am looking for a few experienced service professionals who would like to participate in the evaluation of this new product. Preferably, a candidate would be one who uses micron gauges on a daily basis, has used a number of different products, would be willing to test my product over a number of weeks (preferably in conjunction with their own favorite gauge), and finally, provide an objective evaluation as to its overall performance and usefulness. In exchange for this effort, he/she will be given a gauge from the first production run at no charge, regardless of the favorable/unfavorable nature of the evaluation.
If you wish to be considered, please send me a private message, and I can provide more details. Thanks, JoeyD |
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#32 |
Junior Member
Trade: Tech
Join Date: Sep 2010
Posts: 3
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![]() Re: micron gauge
I'm with Earl. Refrigerant is way to expensive for this kind of money wasting.
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#33 | |
Junior Member
Trade: HVAC installer
Join Date: Sep 2010
Posts: 5
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![]() Re: micron gaugeQuote:
![]() _______________ Plumbing Boston is my life's work . . . avoiding Jersey, where my wives lurk. ![]() Last edited by HVAC Joe; 11-07-2010 at 04:38 PM. Reason: grammar and smiley |
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#34 |
Junior Member
Trade: Heating and Air Conditioning Service and Installation Tech
Join Date: Jan 2011
Location: Chalmette, LA
Posts: 5
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![]() Re: micron gauge
What kind of micron gauges are you guys using? I was using a Fieldpiece SVG2 for about a year now and it is already crapping out on me (it reads 1880 microns when open to the atmosphere). I need something durable and worth the money. Fieldpiece makes a great Electric meter and amprobe however their vacuum gauge and superheat/subcooling meters are not up to par even if you baby them.
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#35 |
Junior Member
Trade: HVAC
Join Date: Feb 2011
Posts: 1
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![]() Re: micron gauge
digital gauges are more accurate and also expensive
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#36 | |
Junior Member
Trade: HVACR COMMERCIAL SERVICE TECH
Join Date: Jul 2009
Posts: 1
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![]() Re: micron gaugeQuote:
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#37 |
Junior Member
Trade: c20
Join Date: Feb 2012
Posts: 3
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![]() Re: micron gauge
I used to use my sman3 and my JB micron gauge every time. now that I have a testo 557 I use it and the JB. I do this because i noticed that sometime the micron meters get stuck in a vacuum even when exposed to atmospheric pressure. I think its worth it though for the customer and of course I pride myself on having a low rate of call backs.
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#38 |
Junior Member
Trade: HVAC/R Technician
Join Date: Nov 2010
Location: WI
Posts: 8
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![]() Re: micron gauge
As for which micron gauge is the best, the Bluvac hands down.
With the leak rate indicator you can tell exactly what is happening inside the system. It is very sensitive and will reveal any leaks in your vacuum setup. It is the one JoeyD talked about in his post above, from Aug, 2010. Last edited by chuckcrj; 04-20-2012 at 09:29 PM. |
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#39 | |
i am that guy
Trade: Service man
Join Date: Jun 2009
Location: NW Ohio
Posts: 32
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![]() Re: micron gaugeQuote:
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#40 | |
Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 884
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![]() Re: micron gaugeQuote:
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