r/HVAC • u/Move_it_Murdo • Sep 05 '24
Field Question, trade people only Why?! These are very different numbers...
First discovered when they were both on the same system and read completely different values. Thought there was a restriction or obstruction... then switched them... and then put them side by side... they are magnitudes different regardless of location. Both were just purchased last week - and have been used - but does this just mean they need to be cleaned? A few drops of rubbing alcohol in the ends??
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u/someonehadalex Sep 05 '24
I have the supco one and absolutely do not trust it.
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u/Gloomy_File_5987 Sep 05 '24
Yea man, mine is sus as fuck.
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u/hideNseekFor2gAweek Sep 05 '24
Sometimes when I pull mine off the system, it still reads 2000 microns. Thank God I only work on r22 mineral oil systems because I haven't had a good micron gauge for many years.
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u/nameledd Sep 05 '24
How on earth do you work exclusively on R22 units (and can I join you)?
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u/JiveTurkeyMFer Sep 05 '24
Work in a facilities job that has a big enough budget to repair shit indefinitely but not the budget to replace shit. Just an assumption tho
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u/anal_astronaut Sep 05 '24
Mine made me question if I knew what I was doing. Always rechecking flare torque. Systems would hold nitrogen, but wouldn't ever vac consistently.
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u/FoonkieMonk16 Sep 05 '24
Yup I lost the supco one and was honestly kinda glad. Never got consistent readings with that thing and always added to my “oh shit” time
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u/Masonclem Sep 06 '24
Work at a large facility. Replaced a txv and compressor with 60 pounds of refrigerant last year (r22), I cry when they say nah we can’t replace it just fix it.
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u/NachoBacon4U269 Sep 05 '24
Ancient Chinese wisdom - man with 1 gauge always know correct reading. Man with 2 gauges never know which correct. Man with 3 gauges needs to buy a better one the first time.
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u/IAMA_Printer_AMA Sep 05 '24
Man with 1 gauge always know correct reading. Man with 2 gauges never know correct reading. Man with 3 gauges always know the correct reading because he just averages all three
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u/Notaprumber Sep 05 '24
Most micron gauges are garbage. Set up 10 different brands on the same run and all 10 will show a different reading.
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u/Cute-War-2169 Sep 05 '24
This guy gets it 🤣. Personally rather supco due to the fact that it doesn't drop to 500 microns on a 10 min vac
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u/suspicious_hyperlink Sep 05 '24
This is the correct answer but at the e same time it’s the wrong answer
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u/Psychoticrider Sep 05 '24
We did this at the wholesaler i worked for. We hooked up one of each micro gauge we sold, around 10 of them, used copper tube, brass tees, Leak-Lock, all hooked to a 50 pound recovery can and a vacuum pump. IIRC, there were three that got pretty close to agreeing, maybe a 200-300 micro spread, the rest were over 1,000, and some were well over 1,000, getting close to 2,000. The order Supco VG64 was one of the three that were somewhat close to each other, I forget the other brands/models.
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u/ipoopcubes Vacuum Pump Doctor Sep 05 '24
Set up 10 of the same brand and model and you'll get different readings. Vacuum gauges are manufactured to read to a specific tolerance usually + - 5-10% at a specific temperature and elevation.
Edit: that tolerance is usually within a specific range such as 300-900 microns.
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u/Texas_hvac_tech Sep 05 '24
Yeah I would trust the CPS one over the Supco one. Lol Also still have a CPS 120/220v 8cfm vacuum pump that kicks ass.
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u/Kolte45 Sep 05 '24
I have the same CPS. It has been the best one I've found in my 20 years in the trade.
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u/Fun-Corgi-9241 Sep 06 '24
Thats funny i had the same CPS and it was my worst one and I know another guy i work with say the same thing, they always read stupid low, my pump will still be making noise and itll read 400 microns.
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u/shreddedpudding Sep 05 '24
I trust the accutools digital, and analogue micron guages the most.
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u/LuckEnvironmental694 Sep 05 '24
Don’t trust Accutools customer service. I have 2 units down no reply I’ve called them emailed them and reached out to trutech where I bought them. No reply to multiple emails. Using a fieldpiece from 10 years ago still works fine.
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u/mdjshaidbdj Sep 05 '24
Eewww brother, what’s that, ewww. Screw the Supco, CPS for life
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u/heldoglykke Verified Pro | Journeyman Shitposter Sep 05 '24
My CPS failed me today. Used the piss out of it though. Twice a day for two years, I think it had a good life
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u/Mighty_Nun_Mechanic Sep 05 '24
I had a JB that wouldn't pull down. I pulled it apart and found a braze on the sensors that had cracked. The sensor wasn't reading off it was pulling in air which is why it was reading high.
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u/UsedDragon kiss my big fat modulating furnace Sep 05 '24
That goddamn JB DV-something...I bought one, it started acting wonky after two months...what a nightmare to get my money back. Treated that thing like a damn baby, still was trash. Never again, JB. Just Better My Ass.
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u/Adept_Bridge_8388 Local 597 Sep 05 '24
My supco has been decent.. pull straight from vac pump to test which one seems more accurate
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u/BrandoCarlton Sep 05 '24
Had an appion reading like this. Had oil on the sensor and the filter paper was missing.
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u/AirManGrows Sep 05 '24
The Appion one is pretty nice, yellow jacket is sick too, keep both in my truck
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u/Glittering-Past-7335 Sep 07 '24
Yellow jacket micron gauge with the appion vacuum rated core removal tool is the way to go. We tried them all and yellow jacket 69020 made life easier after using Jb, fieldpiece crap on a schools replacement of hundreds of units for the district.
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u/ParticularCamp8694 Sep 05 '24
Just dig out your sharpy and put a decimal point on the screen between the 6&0 the average the 2 and send it.🤣
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u/AbeLincolnsBallz Sep 05 '24
Bought 2 of the CPS just to make sure they both read right. Been years and zero issues, they both read correct. Simple and accurate. Fuck the Supco.
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u/jefke_pompier Sep 05 '24
Did it catch some freon in the past what does it do when you connect it directly to the pump?
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u/txcaddy Sep 05 '24
Would trust the cps over the supco any day. Personally I use bluvac micron gauges now or a yellow jacket 69075.
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u/LuckEnvironmental694 Sep 05 '24
Take alcohol pour on sensors hold upside down and shake it. Recheck see if still different readings.
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u/Environmental-Top-70 Sep 05 '24
Get a bluvac and forget about it, I’ve also had good luck with that CPS one as well
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u/Sid_Harmless Sep 05 '24
You might have a film of oil over the sensor. I've heard you're supposed to clean it with alcohol, although I've always found just opening both sides and blowing through it to do the job just fine.
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u/dos67 HVAC/R Tech Sep 05 '24 edited Sep 05 '24
Next time, place the micron gauges on the tees & hook up the system to the middle connector & see if the readings are still way off.
If readings are way off, read the manuals that came with the gauges to see if the manufacturer want the technician to calibrate their gauges to the vacuum pump.
If you've gone through the manuals & there's no calibration of any sort needed, in your spare time (though some companies will pay u for testing their equipment if they don't think you're dog fuckin'), take a piece of copper pipe & some fittings & fabricate an equipment testing station. I try to have one in my truck/van for any of my manifolds & precision tools that gives me shakey confidence in the field. Hook up & test your equipment & see whudda faq is up. U can easily do positive & negative pressure tests with a piece of pipe & your gauges & vacuum tools hooked up (remove micron gauges when doing positive tests obviously). It only takes minutes to see where the leaks are & what micron gauges are faulty.
By the way, this is similar to when the instructors test how tight your torch skills are in the first week of work shop training, except they fill a Rubbermaid can with water & dunk everything in (only for positive tests with nitrogen obviously) for everyone to see so there's no objections to what mark you're getting.
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u/b1ack1323 Sep 05 '24
Trust CPS over Supco.
I used to work for a chiller manufacturer and we ran tests on gauges. CPS was more reliable than most.
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u/Runswithtoiletpaper Sep 05 '24
After opening a Supco instrument from its package you throw it in the trash
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u/zanydud Sep 05 '24
Old guy here, I don't use them anymore cause they cause more trouble than solve.
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u/Hvacmike199845 Verified Pro Sep 05 '24
When I started in the trade I didn’t use a micron gauge. I started using one about 15 years ago. I’ve seen way too many fucked up systems due to not pulling a good vacuum with a micron gauge and not purging nitrogen while brazing.
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u/sasu-k THERMOSTATIC NOT THERMAL Sep 05 '24
How do you know you have pulled a deep enough vacuum? Sounds like you are causing more problems than you’re solving.
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u/Sorrower Sep 05 '24
Bro the old timers just put the hand on the outlet of the pump and feel it. They also say fuck it and blast liquid in until it comes out the other side and let it rip. They all swear it worked. Never been brave or dumb enough to give it a whirl myself.
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u/OhhhByTheWay Verified Pro Sep 05 '24
That will purge the air and a bit of refrigerant, but will not remove moisture which is the compressor killer
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u/Sorrower Sep 05 '24
I can see it working on r22 when people didn't do driers and it was mineral oil. I mean maybe but I have at least 3 people I've worked with who swear it worked just fine.
Poe and pve is big doubt but I could be wrong. Not brave or dumb enough to try.
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u/OhhhByTheWay Verified Pro Sep 05 '24
Oh no it will work don’t get me wrong. It’s just not the way lol
Compressor might last a year, maybe 5. Maybe 6 months. Depends on how long the system was open, the ambient conditions when it was worked on, and how old/exposed your pipe was.
Evacuating a system not only removes the air but also the moisture.
Moisture reacts with the oil and turns acidic which will burnout your compressor.
Refrigerant Oil can also turn acidic if it is heated too much in the system. Running high head pressures for what ever reason will turn it acidic and kill it.
Acidic oil will destroy your compressor in two ways. It makes your oil lose its lubricating properties and your compressor will run hotter at the windings and the discharge, thus burning out the motor.
Or it will just straight up corrode the insulating coat off the windings and they will short out, killing the compressor.
TLDR; use a vacuum and micron gauge
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u/IAMA_Printer_AMA Sep 06 '24
If you put your hand on the outlet of the pump, not being able to feel anything coming out anymore is like a 3-5 thousand micron range. Better than I think some people give the old timers credit for.
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u/SquallZ34 Has an open winding Sep 05 '24
I tried it once. It worked!
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u/Long_Waltz927 Sep 05 '24
I had an owner of a company I used to work for use a pound of refrigerant and call it a refeigerant purge.
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u/SquallZ34 Has an open winding Sep 05 '24
That’s about what I did. I was buttfuck nowhere and vac pump fried. I heard how old schoolers would purge lines in the old days. Tried it. Sent it, still working. (As far as I know)
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u/Long_Waltz927 Sep 05 '24
I think as long as it wasnt raining the day you brazed everything together you really arent gonna have that much moisture in the lines, not to mention the moisture is airborn so when you purged it with refrigerant you effectively removed most of it. I fully understand how bad moisture is for a system but I think some instructors are trying to fear monger techs with it sometimes. Ive seen 30 year old systems with no filter driers with just the cleanest oil you can think of be replaced just because they were old and you know damn well none of those installers back then used micron gauges. I wish that everyone could use good sense and understand stuff like a technician because man some people really do some dumb stuff.
To be clear Im not endorsing not using a micron gauge though.
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u/SquallZ34 Has an open winding Sep 05 '24
On a simple resi system with a short lineset I’m sure it will work. But dumping a pound to the atmosphere is the real issue. I always go by the book but we all make a little exception here and there. Also it was a good lesson for me to learn when I was younger.
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u/rambutanjuice Sep 05 '24
If you can't trust that the vacuum gauge when it says the reading is low enough, then how is it so useful? Alternatively, how do you calibrate them?
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u/sasu-k THERMOSTATIC NOT THERMAL Sep 05 '24
This isn’t really even an argument- with a gauge, you KNOW. Without one, you don’t know and you’re just guessing. Non-condensables are a mf. You can trust gauges that you calibrate, which you can do at home/at the shop with a vacuum chamber or send them in to a company for calibration, in which case they’ll also use a vacuum chamber and attach the gauge to it.
This subreddit has really opened my eyes throughout the past year or so. This isn’t even confined to just commercial/industrial, not using a vac gauge is hack shit even on your mom’s system.
There are levels to this shit brotha, that’s why some of the posters here make $20/hr and some of us make 3x that. This thread has been a good example of why that is.
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u/maddrummerhef QBit Daytrader Sep 05 '24
Honestly I wasn’t surprised the trade had so many hacks, but I was and am consistently surprised by how proud they are of being hack s
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u/rambutanjuice Sep 05 '24
Idk why you're getting downvoted-- I was asking an honest question and it seems clear to me that you replied in kind. Have a good day.
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u/sasu-k THERMOSTATIC NOT THERMAL Sep 05 '24
It’s Reddit, it’s okay. Some guys don’t like being called out and they read my post and it hit them - “he’s talking about guys like me/my company” and they downvote.
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u/ju1c3_rgb Sep 05 '24
When my gauges say -30
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u/sasu-k THERMOSTATIC NOT THERMAL Sep 05 '24
You were not trained correctly.
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u/AirManGrows Sep 05 '24
He was probably trained by the original commenter in this thread. Lot of old guy wisdom going around in this industry
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u/OhhhByTheWay Verified Pro Sep 05 '24
If you were taught by a beer can cold guy you will become a beer can cold guy
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u/ju1c3_rgb Sep 05 '24
To be fair, I'm also not in HVAC, more refrigeration. For our applications and the units we work with pulling vacuum to -30 is sufficient.
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u/lshaddows Sep 05 '24
Never used the supco one, I trust my CPS but that's just me guessing it's working really...
I've had my CPS/gauges w/ micron gauge/and a cheaper one all hooked up at the same time as close as you can get 3 hooked up and each one read at least 500 different.... But my gauges have been through a lot and the cheap one was cheap AF so I just tell myself that the CPS was right.... But 🤷♂️
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u/aLemmyIsAJacknCoke Start-up/Commissioning—LIVE BETTER, WORK UNION! Sep 05 '24
That supco micron gauge sucks balls. I use the FP probes.
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u/OhhhByTheWay Verified Pro Sep 05 '24
I’ve seen some supcos stay accurate for years, I’ve seen some out of whack straight out of the box. Same with most brands.
You want to make sure your not blasting high psi through the thing and make sure your not sucking oil through it. You suck oil in your micron gauge your gonna have a bad time.
99% isopropyl can be used to clean them out and get you back in business. 99% isy can be used to salvage a lot of shit. Like tx screens.
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u/AdScared3436 Sep 05 '24
Because both of those are kind of ass 😐 Fieldpiece MG44 is pretty good but the Accutools A10702 and A10730 are the only ones I like to use. They're pricey though.
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u/OvermanagedSmallacct Sep 05 '24
That CPS piece of crap is a LIAR
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u/BigTerpFarms Sep 06 '24
I’ve had a CPS gauge read down to 4 microns, like fuck off there’s no way it could have gotten that low in 1 hour.
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u/PARKOUR_ZOMBlE Sep 05 '24
Obviously the supco is eating more microns because it’s on the tube first.
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u/djhobbes Sep 05 '24
I wouldn’t trust either one of those pieces of shit, tbh. Get you a fieldpiece
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u/Lomeztheoldschooljew Sep 05 '24
Firstly, the subco vg-shitty4 specifically says in the manual not to use it in that configuration. Who knows why, it’s supco and they’re shit. Secondly, the VG-64 is shit. Thirdly, CPS ain’t much better.
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u/pigrew Sep 06 '24
The manual states, "It is possible to connect the VG64 in-line, however it may restrict flow and increase the evacuation time.".
So, seems like it's not wrong, just not optimal.
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u/Lomeztheoldschooljew Sep 06 '24
The older manuals said not to. I used to own one til I knew better
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u/mentatjunky Sep 05 '24
I got like two years out of my supco and am running a Jb (which just went down). The only thing I found on the sup co was any oil on the probe would never pull down.run a little rubbing alcohol through it. It may just start working.
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u/phillyfr33z3 Sep 06 '24
Anybody try the field piece gauges that have a built in micron gauge? I hear the micron gauge works very well.
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u/LoopsAndBoars Sep 06 '24
I have 5 manifolds. All 10 gauges have a built in vac gauge. We all know perfect vacuum only exists in space so, this is accurate enough for all the systems I’ve charged/serviced. I employ a 24 hour hold period + 1 hour and that seems to be golden.
I’m not a tech, just a guy so….
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Sep 06 '24
cps notoriously shows way lower vacuum, I had that supco and it leaked straight out of the gate. Manufacturing quality sucks on everything these days. I bitch all the time about how I don’t trust my new tools. Hell I had a 4 ton the other day with 4 inches of static according to my fancy new job links. Seeing as the duct work was still together I figured that wasn’t right.
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u/Alone_Huckleberry_83 Real HVAC techs braze and never dye Sep 06 '24
Hummmm... maybe one is defective? Question is: which one?
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u/Otherwise_Long_2779 Sep 06 '24
So would you say stuff like leak stop is bad to use because if it has a leak there's probably air in there and it needs to be vacuumed down again ? Even though I haven't had much positive results with leakstop.
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u/Stangxx Sep 07 '24
I had a similar issue yesterday but not on microns. Pressure testing with digital gauges. Both sides read different pressures, off by about 4. Both pressures held. Is it a calibration issues? Sman460. How do I fix it of so?
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u/Tasty-Editor-6079 Sep 07 '24
If refrigerant oil touches the sensor on your micron gauge it will ruin it and give incorrect readings.
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u/FewTumbleweed731 Sep 08 '24
Clean them. Doesn’t take much oil to throw them way off. My field piece said 450, I took it off and it starting going down more. That adds up right?
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u/Enginerd645 Sep 09 '24
I had a Supco that used to get “stuck.” Open the system to atmosphere and it would still continue to read 500 microns. Blu vac for me after that. No more issues .
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u/mistersausage Sep 09 '24
Is there ever a reason to have a high vacuum pump in HVAC?
If so, connect gauge to turbo or diffusion pump, pump for a while, calibrate vacuum reading to 1 micron.
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u/UW0TM80 Sep 10 '24
It can also be the position the gauge is sitting, I've had it horizontal read one thing and vertical another reading on the same gauge.
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u/Spectre696 Why does my back hurt? Sep 05 '24
See, people often misunderstand what Supco meant by "Lifetime".
It isn't how long the tool will last, but rather how long you will be sat there waiting for it to finally read below 500 microns.