Can You Trust Your Micron Gauge?

[@nsboost]

How “accurate” they are isn’t all that important as long as it isnt substantially off. It’s more of a reference to make sure we are getting the system into a deep vacuum… and to make sure the system is good and tight. Kinda figured we’d have a 50-75 micron variance between all the brands

[@HVACShopTalk]

You figured right

[@gabooda2380]

Using a micron guage doesnt prove there isnt a leak. First its my understanding it doesnt even measure vacuum but rather temperature. Second a vacuum pump will overcome any leak in the system that isnt substantial and a 5min leak test isnt realistic. I even called the techs at one of the major companies and he even said " to have an actual micron guage would be in the thousands, its promoted to ensure people keep their pumps on longer." Last point. A perfect vacuum is only -14.7psi. Good luck if you think that is a suitable pressure test.

[@nsboost]

@@gabooda2380 nice KZbin science there bud. “I called” and “I talked to” doesn’t mean shit. It means you got another persons “opinion”. I’ve had units hold 350psi for 24 hours without a kick of drop.. then leak under vacuum. Pressure test it.. vacuum it deep… and make sure it holds a decay. If there is a leak that passed that stuff.. then it is what it is. People who work in the real world know that half this “by the book” shit doesn’t translate to something that is reasonable in the real world service calls. I work on a lot of junk. And I flat would be out of a job if I spent the time chasing the half the crap I learned was “right”. I dare you to take a 25 year old cooler, make a repair, and try to even get that thing to pull down to “proper vacuum” and hold a “decay test” You’ll spend the entire day pulling your hair out as the oil in the compressor releases refer under vacuum causing you to fail the 5 minute decay test you say “isn’t good enough”. System is tight, refer boils out of oil. Madness in-sues while you try to find a leak that doesn’t exist. But based of your comment you don’t do anything but new installs. So keep living in your fantasy land till you go do service. Hopefully you end up working with a guy who’s been doing it for awhile and slaps some sense into you.

[@gabooda2380]

@@nsboost My "fantasy world" you speak of started in '92. I have been in the field pretty much EVERY day since. I work on both new and wet systems. So, I dont need anyone to "slap some sense into me" Also, my "youtube science" facts you talk about came from an engineer/tech at one of the major test instrument manufacturers. Its a shame hes such an idiot by your standards. But you could always do your own research regarding vacuum transducers, thermistors, and even pirani sensors. Hell, the fact that many micron guages are constantly recalibrating should be a clue. The micron guage doesnt measure vacuum pressure directly. It measures temperature or thermal conductivity/heat loss of the air around the sensor. It measures the cleanliness of the system. Refrigerant doesnt need vacuum to boil off. Moisture does bc we dont live in a 212°F ambient condition. With the POE oil you cant even get the moisture out of the oil without a filter dryer. So thats pointless. So as I said holding 500microns for 5mins doesnt prove you dont have a leak. Its possible you have a very small leak in relation to the total system capacity in a clean and dry environment. They "sell it" as the be all, end all "look ma no hands" and its not. Its just another tool whos reading needs to be interpreted based on the situation. On a wet system maybe a person should blank off his guage mid evacuation and clean it the same as changing his pump oil?

[@fcholman]

I have two CPS vg200's. #1 I bought a year ago and just put it into service a few weeks ago. I wanted the reassurance of its accuracy, so I ordered a second one (#2). #2 is always approximately 2 times the measurement of #1, no matter if a light, medium, or deep vacuum. Always a 2:1 ratio. I called CPS tech support and the tech said that the calibration is done at the factory. A nice guy, and he didn't outright say it...but I sensed that there have been some issues. Now to order a third, and hopefully, 2 of the 3 agree.

[@larryblake7554]

Big Blue will also take care of some wasps…I took out a whole nest with it.

[@HVACShopTalk]

I will remember that tip.

[@RoastedHVAC]

Good to know... Might come in handy. They've been crazy recently.

[@rcinfla9017]

Most vacuum gauges work on thermal heat transfer through gas (or lack thereof in a vacuum) medium. When vacuum gauge gets internally coated with oil and other contaminates it can affect their reading. Higher vacuum has less heat transfer out of thermistor, so sensor applied heating current is reduced to keep sensor at same temperature. This is what the gauge is measuring. Refrigerant oil or other contaminates on thermistor sensor creates thermal insulating mass around thermistor impeding the true thermal insulating effect of the vacuum around the sensor. Light oil coating slows down response, a lot of oil can form a physical bridge between the thermistor and outer brass shell creating a thermal leakage path from thermistor, totally screwing up vacuum reading. Most vacuum gauges allow you to clean them out with some 91% isopropyl alcohol into the Shrader port then lightly shaken to dissolve and flush out the oil. Good practice to have a vacuum rated ball valve on vacuum gauge you can close off before breaking system vacuum with refrigerant. This reduces possibility of refrigerant and oil getting into vacuum gauge keeping it clean.

[@NorCal-refrigeration]

I’ve had a bunch of brands most have died at some point.

[@HVACShopTalk]

That’s what they all have in common.

[@techti8792]

Which one you recommend to rock with?

[@NorCal-refrigeration]

@@techti8792 the new Fieldpiece looks good wireless and has a screen

[@itz_mohittt869]

Is there any analog vaccum guage for hvac?

[@colingilland3454]

Nice test dude! I have the Yella Jacket P51 set up and the fieldpiece gauge and every time I doubt them it always turns out to be something else at blame, either moisture in the system or a dodgy line connection. I dunno how many hours I have spent pondering over microns and doubting my self!

[@HVACShopTalk]

Me too man. I like doing these tests so I can get to the bottom of this stuff.

[@noahoyeah]

Just had a field piece give me bs numbers till I disconnect and restart. Total disappointment when time is everything

[@Mars4190]

Idk if it’s just mine but that little Yellowjacket one sucks never works for me got the new field piece one

[@punchpunchowned]

Love these videos, thanks man!

[@Zappeon_BMF]

Whatever the number, as long as it holds

[@EverythingHVACR]

Nicely done! 👏

[@HVACShopTalk]

Thank you sir

[@jhhvacplumbing1944]

Cool vid zack

[@realsthvac7942]

Im not sure if I can trust my cps I got a short on my page about it

[@thisisyourcaptainspeaking2259]

What system has a pressure of just 150psi?

[@ColemanGlascock]

Trane

[@stephwaylonwells3218]

👍

[@mikehamby9883]

I trust my gauge but not sure about the guy on the right side of your face in the outro.

[@HVACShopTalk]

I’d say you’re wrong about that then

[@clintglasgow5633]

Hart channellocks 👍

[@HVACShopTalk]

Starting to try out their power tools as well.

[@bphc1969]

Idk bud looks like you got new vs old models there on the micron gauges….wish I was rich so I could send u the new Fieldpiece….

[@HVACShopTalk]

I tested my personal gauges so there is a mix.

[@timrob0420]

Where is the king? BLUVac??

[@HVACShopTalk]

These gauges are the ones that I personally own

[@evaluatorhvac4400]

It’s disappointing you have to lower your standards due to the lack of quality products that are available for us to purchase in the market 😢

[@sknight0391]

That test really "sucked" 😉👌

[@HVACShopTalk]

Outstanding Comedy

[@sknight0391]

Outstanding test. Good show old boy, Good show.

[@realestateservicessaleshea99]

As long as you place the micron gauge in the proper place reading the system, and not reading the vacuum pump. 🥃🥃🍺😂🍺🍇🏌🏻‍♀️ Stay safe. Retired (werk'n)keyboard super tech. Wear your safety glasses

[@HVACShopTalk]

I was going to follow this video up with a video where I show the difference between micron readings during the vacuum when the gauges are in different parts of the system.

[@kangaroogod]

Zack that rig sucks

[@HVACShopTalk]

I get it

[@coldfinger459sub0]

New title ( how precise are the technicians at knowing where and how to set up the micron gauges) (“ do the technicians even understand the different decay rates that should happen on different systems but blame the micron gauge ?”) Or the technician that blames the refrigerant gages manifold. , because he’s trying to pull a vacuum through refrigerant hoses and it’s failing the Decay test there is a failure all right and he’s looking at it in the mirror

[@HVACShopTalk]

I’m gonna follow this video up with some stuff that might address a few of those things as well.

[@coldfinger459sub0]

@@HVACShopTalk do one with an old compressor filled with old used oil attached to your line set. Bring down the vacuum and hold and let it decay and steady out. Then strike the bottom of the compressor with a small 2 pound mallet and watch what happens.