# micron gauge



## evapman (Jun 17, 2009)

How many guys use them? I'm a believer in them, allot of guys around here just use their gauges and let the vac pump run fo a hour or so and call it good, and get away with it. How they know the system is evaced. I don't know, have seen it take an hour to 3 hours to get down to 400 microns. :yes:


----------



## mechanicalDvr (Jun 25, 2009)

A micron gauge is the only way to tell what condition a system is in. You may get away with a quick vacuum for an a/c system but it will never be good enough for low temp refrigeration.


----------



## johncavh (Jun 21, 2009)

anybody having problems with yellow jacket gauges:sad:


----------



## G 71 (Jun 18, 2009)

evapman said:


> How many guys use them? I'm a believer in them, allot of guys around here just use their gauges and let the vac pump run fo a hour or so and call it good, and get away with it. How they know the system is evaced. I don't know, have seen it take an hour to 3 hours to get down to 400 microns. :yes:


 We all use them, not to use one is just guessing.:laughing:


----------



## jvegas (Jun 17, 2009)

I use one on every system I install the only way you can be sure


----------



## Yuri (May 28, 2009)

It is ABSOLUTELY important that you have clean fresh oil in your vacuum pump or it will take forever to get a 500 micron vacuum. The moisture in the oil from the other jobs etc boils off and slows everything down.


----------



## DuMass (Jul 7, 2009)

I'm wondering how you can really work without a Micron gauge, especially these days with refrigerants that can fractionate when leaks occur and the sponge like moisture absorbing qualities of POE and even PAG if you do automotive AC. :001_unsure: You really need to know that the system is dry and tight.


----------



## mechanicalDvr (Jun 25, 2009)

I know that you can't pull any moisture out of POE oil but I just feel better about any job when I know it was in a good deep vacuum before I charge it.


----------



## sgthvac (Jun 13, 2009)

I also use a micron gauge, don't like guessing. To speed up the vacuum oil must be changed after every use of the pump and use nitrogen before you start. It absorbs soem of the moisture in the system. I will run the pump 10 min. then break the vacuum with nitrogen blow the nitrogen and then vacuum. usually takes about an hr. Replaced TXV on Water Furnace today vacuum took an hr and had 385 micron using this system.


----------



## sanpyon (Aug 6, 2009)

vacum gauge very important,especially on low temp system and you have to keep your oil in good condition all the time.:yes:


----------



## mechanicalDvr (Jun 25, 2009)

I agree you need to keep your oil in good shape, I take mine out for walks on a regular basis.


----------



## NoTime (Aug 11, 2009)

Thanks for the chuckle.


----------



## Gas63 (Mar 30, 2009)

definitely need one with pulling down on 410 system. you leave any kind of moisture and you will kill that compressor. 410 non forgiving


----------



## Aiken Colon (Jun 17, 2009)

For you guys that are also considering digital guages the Testo 560 has a built in micron guage.

Testo 560

They also make one for ammonia

Testo 560 Ammonia

JJ


----------



## Jeffrey Jay (Sep 22, 2009)

Great thread. 

Micron tells the story.

I keep one of those nilla folder type paper tags with the wire on it attached to my vac pump and log the date when I change the oil. :thumbsup: 

Digital gauges are the way to go...just too much dough for me. 
Would be cool if they had a speedy bar graph like my Fluke 87 in addition to digits so you get a visual sweep if something unexpected happens.


----------



## beenthere (May 30, 2009)

Gas63 said:


> definitely need one with pulling down on 410 system. you leave any kind of moisture and you will kill that compressor. 410 non forgiving


Slightly incorrect info there.

R410A, doesn't care if moisture is in the system or not. However. POE likes to absorb it. And then react with the winding.

If you ever add POE to a system. You are adding moisture to the system. unless your buying a new container of it everytime you add oil.

Next. You can't vacuum moisture out of POE. So anytime you open an existing system to replace a part between the service valve and the compressor. the POE oil will absorb moisture. And you won't be able to vacuum it out.
This is why you are suppose to change the LL filter drier when ever you open a system. So the LLFD can remove any moisture left in the system.




PS: On mineral oil systems. Moisture that is under the oil, won't be removed by a vacuum either. This is one of the reasons a triple evac is recommended. It stirs up the oil and moisture in the system, and helps bring the moisture up from the oil.

If you suspect moisture is in the compressor. Then use a heat gun on it while vacuuming the system.

Contrary to popular belief. POE has been around and used long before R410A came out.


----------



## TH3 M0L3 (Jan 17, 2010)

mechanicalDvr said:


> I know that you can't pull any moisture out of POE oil



Um, yes you can. I really cant see the wide spread use of POE oils in modern refrigeration if it hold moisture. Moisture, as you know, is the arch enemy of any fridge/ac system.......

The fact is, you can't tell if you have removed the moisture from the system if yo have not used a vacuum gauge. 

Just out of interest, how many of you perform a vacuum rise test at the end of your vac to check for moisture?

If you have done a strength and tightness test you know there is no leak, so the vac should not rise.
If you have vacced down to below 2000 microns, all the residual refrigerant in the oil would have boiled off, so any rise on your vacuum rise test indicates moisture in the system.......now is when you refill with Oxygen free nitrogen again and do another vac, or more commonly, a triple vac!

YOU SHOULD ALWAYS USE A VACUUM GAUGE!


----------



## beenthere (May 30, 2009)

You can triple evac all month long. And you won't pull the moisture out of POE oil.
You need filter driers to remove moisture from POE oil.

POE has been used in refrigeration since the early 90's. Its the commercial and residential A/C market that is only catching up to refrigeration.


----------



## TH3 M0L3 (Jan 17, 2010)

beenthere said:


> You can triple evac all month long. And you won't pull the moisture out of POE oil.
> You need filter driers to remove moisture from POE oil.
> 
> POE has been used in refrigeration since the early 90's. Its the commercial and residential A/C market that is only catching up to refrigeration.


most of the oil remains in the sump of the comp, so how will it be filtered?
Yes, some oil escapes the compressor during normal operation, but not enough to carry all of the moisture with it....

Vac Vac Vac 

By your argument, if you suspect moisture in the oil then you should replace it.
As POE is extremely hygroscopic, the new oil charge WILL absorb more moisture from the atmosphere when you charge it.
...Vicious circle....

You can never eliminate exposure to the atmosphere, just minimise it


----------



## beenthere (May 30, 2009)

All the oil circulates through the system.
Most of the oil is in the sump at any one given time. But it all circulates through the system.
If it didn't. Then R410A could use mineral oil. The reason it can't use mineral oil. Is that it doesn't mix well with it. And won't be able to return the oil to the compressor.

If all the oil didn't circulate through the system. Then acid clean up by filters would be impossible. Since the filters require all the oil to pass through them to move the acid.

Next. Even if only the same 10 ozs of oil ever moved through the system. The oil that went through the filter drier would give up its moisture to the filter drier. Be returned to the compressor where it would absorb more moisture from the oil in the sump. Pass through the filter drier again. And give ups its moisture again. And repeat that process until the moisture was at a level lower then what it is, just from opening the oil container.

Now if you don't believe that.

Explain how an acid removal filter removes acid from the system.

Sporlan, and Parker(Sporlan now onwed by parker) have tech sheets on how oil circulates through the system. On how and why acid filters, and filter driers work.


----------



## TH3 M0L3 (Jan 17, 2010)

beenthere said:


> All the oil circulates through the system.
> Most of the oil is in the sump at any one given time. But it all circulates through the system.
> If it didn't. Then R410A could use mineral oil. The reason it can't use mineral oil. Is that it doesn't mix well with it. And won't be able to return the oil to the compressor.
> 
> ...


I couldn't agree more and couldn't have put it better my self!

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  on a system with POE as any moisture in the system will be absorbed by it and impossible to remove. (I do know we don't vac to only remove moisture, we vac to remove all the non-condensables too) 

Not all systems use filter driers, just look at all the splits.....


----------



## beenthere (May 30, 2009)

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.


----------



## TH3 M0L3 (Jan 17, 2010)

beenthere said:


> 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.


I hope I never gave the wrong impression, I always perform a vacuum on any system I expose to the atmosphere.....always!



beenthere said:


> 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.


I think the reason they dont have driers is because it causes extra resistance on the refrigerant. If you use a drier, it will have a similar effect as either extending the pipe run, or adding extra bends in the pipework. For the splits to be more efficient, and have longer pipe runs, the driers are omitted....
I could be wrong though



beenthere said:


> Vacuuming removes moisture, nitrogen and CO2, and O2(combined, even without the moisture they're just air).


You are preaching to the converted :yes:



beenthere said:


> You would be surprised how much moisture isn't removed from mineral oil by vacuuming.


Yes, you are right. I would be surprised. But that, I guess, would depend on how much moisture is in the oil.
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....



beenthere said:


> 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).
> ...


It's the time I lack. I know you will never pull a decent vacuum for as long as you have moisture present, and the jar wont make much of a mess if it did implode....
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.....


----------



## beenthere (May 30, 2009)

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.


----------



## beenthere (May 30, 2009)

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).


----------



## westman (Apr 18, 2010)

Yuri said:


> It is ABSOLUTELY important that you have clean fresh oil in your vacuum pump or it will take forever to get a 500 micron vacuum. The moisture in the oil from the other jobs etc boils off and slows everything down.


Should you change the oil between every job?


----------



## beenthere (May 30, 2009)

westman said:


> Should you change the oil between every job?



Yes, 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.


----------



## earl964 (Apr 11, 2010)

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.


----------



## Mr freeze (May 24, 2010)

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.


----------



## Rusty999 (Jul 31, 2010)

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.


----------



## joeyd (Aug 3, 2010)

*Vacuum Gauge Evaluation*

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


----------



## Air Medic (Sep 17, 2010)

earl964 said:


> 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.


I'm with Earl. Refrigerant is way to expensive for this kind of money wasting.


----------



## HVAC Joe (Sep 24, 2010)

*Summary*



sanpyon said:


> vacuum gauge very important, especially on low-temp system and you have to keep your oil in good condition all the time.:yes:


This sums it up. 'Nuf said. :yes:

_______________

Plumbing Boston is my life's work . . .
avoiding Jersey, where my wives lurk.


----------



## HintonAC-LeoTav2 (Jan 23, 2011)

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.


----------



## nimnux (Feb 14, 2011)

digital gauges are more accurate and also expensive


----------



## rlynch33 (Jul 18, 2009)

*Micron gage*



evapman said:


> how many guys use them? I'm a believer in them, allot of guys around here just use their gauges and let the vac pump run fo a hour or so and call it good, and get away with it. How they know the system is evaced. I don't know, have seen it take an hour to 3 hours to get down to 400 microns. :yes:


i use mine to verify for leaks when i"m done with any repair ETC.. Professionals use them.


----------



## combs custom cooling (Feb 1, 2012)

*i use 2 at the same time*

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.


----------



## chuckcrj (Nov 28, 2010)

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.


----------



## acefurnacefixer (Jun 18, 2009)

DuMass said:


> I'm wondering how you can really work without a Micron gauge, especially these days with refrigerants that can fractionate when leaks occur and the sponge like moisture absorbing qualities of POE and even PAG if you do automotive AC. :001_unsure: You really need to know that the system is dry and tight.


 you cant and should not even attempt to put in a A/C system with out using a micron gauge.I use one every time I install or repair the pipeing side of a system. if i dont achive 50 microns, then i am not sure that my joints are tight. Your manifold is for charging a system......not to tell you if you have a tight system......thats the job of the micron gauge.


----------



## beenthere (May 30, 2009)

acefurnacefixer said:


> you cant and should not even attempt to put in a A/C system with out using a micron gauge.I use one every time I install or repair the pipeing side of a system. if i dont achive 50 microns, then i am not sure that my joints are tight. Your manifold is for charging a system......not to tell you if you have a tight system......thats the job of the micron gauge.


50 microns? A lot lower then needed.


----------



## acefurnacefixer (Jun 18, 2009)

beenthere said:


> 50 microns? A lot lower then needed.


 I have a five CFM vacuum pump......to achieve 50 microns on a tight system is a breeze, it may take an extra 2 or 3 minutes to go from 500 to 50......so why not?


----------



## beenthere (May 30, 2009)

acefurnacefixer said:


> I have a five CFM vacuum pump......to achieve 50 microns on a tight system is a breeze, it may take an extra 2 or 3 minutes to go from 500 to 50......so why not?


Your working on small systems. Many of the ones I work on take a couple hours to reach 300, and would take a lot more then few extra minutes to reach 50.

Even the residential ones I work on would take more then a few minutes to go from 500 to 50 microns.


----------



## acefurnacefixer (Jun 18, 2009)

beenthere said:


> Your working on small systems. Many of the ones I work on take a couple hours to reach 300, and would take a lot more then few extra minutes to reach 50.
> 
> Even the residential ones I work on would take more then a few minutes to go from 500 to 50 microns.


 
maybe its time to change your oil, or your pump......?


----------



## beenthere (May 30, 2009)

acefurnacefixer said:


> maybe its time to change your oil, or your pump......?


I change almost every vacuum. I have 2 pumps and they both take about the same time, my newest one is only3 years old.

Almost every vacuum because sometimes its only a vacuum on a shell filter I just changed out.


----------



## jennewhite (Jan 25, 2015)

*can anyone tell me the benefits of micron gauge?*

I have doubt about this tool.
Thanks


----------



## jennewhite (Jan 25, 2015)

*Because i have that tool. and don't know how to use it.

*


----------



## GaryB (Jul 16, 2011)

sgthvac said:


> I also use a micron gauge, don't like guessing. To speed up the vacuum oil must be changed after every use of the pump and use nitrogen before you start. It absorbs soem of the moisture in the system. I will run the pump 10 min. then break the vacuum with nitrogen blow the nitrogen and then vacuum. usually takes about an hr. Replaced TXV on Water Furnace today vacuum took an hr and had 385 micron using this system.


:yes:
And I was beginning to think I was the only tech doing this. 
I have told the guys at the shop until I am blue in the face. 

Nitrogen will help absorb tiny amounts of moisture, and push air and moisture out of the system. :thumbsup:


----------

