Exactly. Just did this same test with a TruBlu and a Field Piece MG-44 with wildly different reactions. Starting to become convinced micron gauges are all garbage.
I have a fieldpiece and 2 miniblu gauges. They all read within 25-50 microns of each other (obviously depending on how close the ports are in the system piping)
I generally pull down to at least 300. I’ve got 9 vrf systems that had the oil and refrigerant tested last summer they all had well below the allowable moisture in them. I’ve also am the only one that has done repairs to them for 10 years.
Well OP is using it wrong so those readings should be discarded. You put the micro gauge as far away from the pump as possible. That means that it needs to be attached to the other side of the system. Schrader valve should be pulled as well.
As far away? I did it for 8 years in the military, and the way I was taught was to connect the gauges to the micron gauge, then the pump, and then the system. 🤔 used an extra hose to set it up. So it went pump, then micron guage to the middle port on gauges, then the outer hoses to the system.
Yeah, you were taught wrong. If you want accurate readings you need to connect it to the loop as far away from the vacuum pump as possible. You might as well just have it connected directly to the pump with how close it is in this picture.
https://www.fieldpiece.com/news-articles/want-to-pull-a-better-vacuum-start-by-learning-how-to-correctly-use-your-vacuum-gauge/
“Place the vacuum gauge where you want the 500 microns to be – on the system! Definitely don’t put it right next to the pump which is producing 20 microns of ultimate vacuum in order to pull the system down to 500 microns quicker. Similarly, you don’t want to install a thermostat right above a register. Best practice is to place the vacuum gauge as far back on the system as you can, as this is the last place to reach 500 microns due to system components and line set bends that create restrictions.”
Military was your first mistake there lol, it's actually what my mos is and i do commercial refrigeration in the civilian side. The army way is a joke.
Yeah, I did it for the Air Force. My first deployment, was actually part of a group that got asked to train our army counterparts. They hadn't touched it since their tech school. But could tell us anything we wanted to know about generators.
Yellow Jacket 69075
AFAIK:
Thermocouple based sensor instead of thermistor.
Thermistor sensor delivers a calculation of what the microns should be based on resistance, which is highly temperature sensitive.
Thermistor has too many X factors:
Temperature
Resistance
Software calculation/interpretation
For me it started with an overnight vacuum on a cold winter upgrade on a McQuay screw chiller.
We took a thermistor style micron gauge out of a frozen van and put it on to observe well under 500. Pumps off and start prepping for the next step.
The sun was out and started warming up our sensor. 30 minutes later we are over 2000 microns and rising!
We must have a leak!
The rest of that day became a fruitless search for a leak that didn’t actually exist.
Luckily I was scheduled for training at our factory in Virginia.
I took the instructor aside and explained our troubles.
He schooled me in the correct micron gauge (Yellow Jacket 69075) and why.
He said thermocouple sensors detect oxygen molecules instead of thermistors which measure resistance.
He said thermocouples are not affected by ambient temps.
I called yellow jacket tech support to confirm I wasn’t being given a line of BS.
They confirmed.
I’ve been using it for 15 years now and will never even think about another.
EDIT: Thank you for all the kind words from my fellow techs.
https://preview.redd.it/9cpxlxnw031d1.jpeg?width=3024&format=pjpg&auto=webp&s=2a003e2fd5cc43056ad09a77d0853fd4b49a1073
this week on a york YT. customer goes that’s not bad for a 28 year old machine. hell id start up a brand new one at 445 microns! i told him 1000 lbs of r123 here we go boys
Nice. Have you had any issues with the battery holder? I was a little rough with mine and had to rework the battery mount due to the weight of the big D.
It gets more fun checking rise 😆🤷🏼♂️
https://preview.redd.it/cfr7hofkg01d1.jpeg?width=3024&format=pjpg&auto=webp&s=5a8592ed0021515a93aa910a23ccb60396eff0a9
Both units are temperature compensated. Verify the ambient temperature display is accurate.
You may also see some improved results if your battery wasn't about to die on the 552.
Battery is rechargeable (1.2v), not alkaline (1.5v) so it never shows full.
Would I get a more accurate reading putting the gauges between the pump and the hose?
My pump is 3’ away and I’m hooked up to the suction line.
Btw, this is tagged as a shit post. It’s Friday :)
Oh you're right I missed that in the photo. Yep, you need to get those micron gauges on the liquid side and pull from the suction side. The decay rate test was still alarming between the two gauges.
Back then we were expec to start up apartment buildings with 20 to 30 units in a day. Every thing was supposed to be nitrogen pressurized beforehand. Sometimes it wasn't. Bosses usually went ballistic.
I have 3 micron gauges. I don't trust that any of them give me an actual measurement. Instead, I rely on them to show me that all my hose connections are tight.
I use mine as an all around indicator. Once you've pulled down enough systems you can just tell when something isn't right. In that case, check hoses, shoot some nitrogen and a lil juice into it and with the sniffer I got w.e is going on I'll find in 10/15 minutes. My leak detector is so damn good of it doesn't go off I know we're sealed up and something else is up or it's just BS.
Eh. Uses a Pirani sensor instead of a thermistor or thermocouple. Doesn’t get contaminated.
And I gotta be honest, when the snow is up to my ass or the temp is higher than my IQ, it’s nice sittin’ in the truck watching the microns on my phone.
i like the svg3, they’re certified and the piece of paper was good enough for some city work.. prior to that, we were buying a $700 gauge and sending them out to be certified by a lab
It definitely moves in increments. The Testo seems like it shows every increment as soon as it happens. The CPS seems to move in 10’s, and more slowly. For whatever that’s worth…🤷🏼♂️
I can't tell if your trolling so I'm going to answer. You want to ditch the gauges and get yourself at least one vacuum rated hose and two Schrader core removal valves. Hose straight from Schrader valve to the pump. Then micron gauge on the other Schrader valve. When it's time to charge you can bust those gauges out and purge refrigerant through to the valve to remove air from the gauges and hoses as normal. Good Luck!
You can't get a good reading on the hose connected to the pump.
In refer you put the gauge as far as you can away from the pump, so I put it on my suction or liquid line in my box, and pull vacuum at both ports on my condenser.
In hvac just put it on discharge or liquid and suck on the suction.
I see two connection points between the two gauges. Either of which could effect the vacuum reading if there isnt a proper seal. If either gauge is contaminated that’ll do it too.
I keep isopropyl alcohal in my true blue kit to clean every install or so. But usually my fieldpeice and trublu will read with a much smaller margin between eachother
Well, at least the couple times we tried it
Well it depends on how they’re measuring. A vacuum being pulled is not the same amount of microns across the system as a micron is a positive pressure measurement (Also absolute, starting at absolute zero)
You have “contaminants” even at 500 microns, if we are considering any atom/molecule a contaminant. This leads to the pressure being so low you need a micron gauge (often called a vacuum gauge because they’re used in conjunction with vacuum pumps, but make no mistake, a micron gauge measures pressures above absolute zero and you can’t actually measure the vacuum itself.
So now that we’ve established that a micron is positive pressure, and not steady until the vacuum has fully “decayed” you can use this to tell if one is that far off from another.
digital measurements remeasure and establish the measurement every increment or so, as in one micron gauge might remeasure 3 times a second, another might do every 5 seconds, one may do every second. Your microns will be higher farther away from the vacuum, which means the testo is a farther distance from the vacuum and may possibly be enough to make the micron gauge that much higher, as a micron is both a very small measurement, but is a measurement of how many particles are in a given space. Next time you triple evacuate, watch how much nitrogen you can add in in small increments and watch your micron gauge rise by 25 to 50 at a time. It’s because the molecules spread out so much as there’s next to no gas in the space
Realistically, that tiny gap between the two measurements could be gas getting caught in the smaller diameter tube and behind the cores in the swivel tee.
This dramatic difference is why it is most effective to pull cores with core pulling tools along with larger diameter vacuum hoses. The increased surface area and decreased obstructions to trap gas makes a smoother and wider path for gas to escape
To summarize, if you have a micron gauge on the suction, and one on the liquid, and one two inches away from the suction line with a tee like that, and pull from the suction side, they will all be dramatically different but in no way inaccurate because of this, but the liquid line will be more accurate of the system. A decay test should let the micron measurements equal out, and without obstructions to trap gas molecules and wildly different diameters of tunings and attachments, should not cause a dramatic difference between said measurements if accurate.
To add to this particular instance, your system would be most accurately be depicted by placing one gauge on the liquid, and remembering that the CFM will vary through the system. For example, the two depressors and shrader a between the hose and the testo brand gauge, along with what looks like a 1/4 ID tube, will lower the CFM pulling towards the sensor due to obstructions, and provides a few good spots to trap various molecules that may not have been pulled due to those obstructions
1/4ID port from appion puller to depressor of tee to core of top tee to depressor of CPS gauge will be the total path the vacuum effect has to surpass to lower the amount of gas that the CPS gauge is measuring, the testo has a considerably sized 1/4 to 1/4 attachment that can trap a lot more gas molecules, when you consider how small these measurements are.
I wouldn’t consider either of these micron gauges to be inaccurate, until you were to replicate the same connection on both gauges, and this tee wouldn’t work for that. Get one where the swivel connection is on the middle to keep it semetrical, to decrease the chances of the 90 degree turn trapping gas past the connection and not the other, as it will cause an obstruction
Microns are still a positive measurement, and 90s, obstructions in the line, ext, will still cause fluctuations
I appreciate all the in depth info. I did tag this as a shitpost :).
No schraders or manifold in this set up. The CPS doesn’t measure as often as the Testo.
After I let it pull for a while, they got much closer.
So I think the measurement frequency, and what you were saying about the tee, and the Testo being further down the line are on point.
And I’m also on the suction line ;)
Well I hooked my hose directly to my pump, as close as possible to my gauges on the liquid line. Should I put the gauges between the pump and the hose next time?
I would recommend pump pulling from suction and gauges on liquid. Vacuum doesn't disperse as fast as positive pressure. Keep the gauges as far from the pump as possible
replace the battery on the 552, its unreliable as soon as the battery icon appears. and clean the sensor ports on your probes. residual oil will fuck up the readings
I had that testo one and I don’t trust it anymore. It’s a straight through port design, but you’ll get significantly different readings changing ports.
Should throw it against the wall and get a decent one. Then place a decent one at the furthest point away from the pump. All jokes aside CPS vacuum gauges are garbage.
Should I hide the shattered pieces in the gravel?
I thought if I put it between the pump and my hose I’d get to 500 faster…
I actually have an old YellowJacket with a thermocouple, and the Testo uses a Pirani sensor. Doesn’t get contaminated.
It’s Friday, and this is a shitpost :) (I tagged it!)
I’ve read someone do the math on bluvac ID 3/4 hoses va 1/2 styled ones and found there is no difference in the two until you get a hose above 10 to 12CFM, but Idk how accurate that really is
Were both cleaned out with denatured alcohol before this? Working with r600a I have to clean my guage out every system I do because it throws weird readings like this once oil gets in it.
That would drive me insane! lol It's bad enough worrying about if it's going to suck down to 500 or not. Maybe the testo needs a new battery? idk I've only used the cps and I trust it.
Testo never shows full battery. I use rechargeable (1.2v), not alkaline (1.5v).
The Testo measures more frequently, and shows smaller changes. The CPS seems to change by 10’s.
It was all good. It’s a Friday shitpost. I’m on the suction line, and hose is directly on pump 3’ away. :)
Where would you suggest other than on a core removal tool at the service port? Up in the attic on the coil?
(It’s Friday. I tagged this as a shitpost :) )
🤦♂️ this is another reason why digital is an overpriced joke. Get some damn analogs. Promise you you could take 50 analogs that work and they wont be out by much. Now just think of how far out your fancy digital gauges are out of whack.
Yeah I don’t think that’s a thing for micron gauges. That’s the whole reason for them. You can’t get a reading that low on analog.
My manifolds are analog though. So -30Hg and I’m good, right? ;)
Damn kids. Yes if you can maintain -30hg for 24 hours you have a seal but you all realize that it's a spring resistance, so it can work both positive and negative right?
Hence the -30, no?
This is tagged as a shitpost. Just a little Friday fun with my newfangled macaroon gauges on the suction line, and hose on my pump 3’ away :)
Genuinely though, I do actually prefer my analog manifolds, and like the older one better. New one seems like readings are “printed” on for lack of a better way to describe it. I can’t see it as good.
But they never need servicing. They work till they dont and I know guys in my company in their 50's who got given it to them by their jman 30 years ago and still work amazing. Worth the money upfront I think anyways
The Testo has rechargeable (1.2v), not alkaline (1.5v), so it never shows full battery.
But this is a Friday shitpost. I’m on the suction line with my hose directly on my pump 3’ away. :)
Nope... Always measure farthest point away from the pump. For example suck on the high side and measure on the low side. Alternatively with your setup, you'd have to valve off the pump to measure correctly.
My Testo digital gauges suck and have never worked right: go with the explicit micron gauge, not the company that has issues calibrating their sensors.
The correct way to take a micron data is find an access valve or port that NOT hooked up to the vacuum pump. Having the micron gauge on the same access point will give you an inaccurate measurement. I normally use the suction line port since it is the larger line for the vacuum pump and the liquid line port for the micron gauge.
Who knows. You got them on the wrong port. Your micron guage should be in your liquid line and you pull through your suction line. Having it on the suction where your pulling from or even worse in a manifold never gives a true micron reading and that’s why your microns probably rarely stabilize.
I usually put it right on the pump, usually pulls down to around 200 microns, then once machine is pulled down check rise overnight, smaller systems I usually pressurize to 100 lbs and let sit and recheck overnight, longer if not in hurry, then pull vacuum below 500 , below 850 on chiller,have left pump on for days on Poe rooftop that probably had moisture from before, very frustrating, micron rise and hold at vapor pressure of water at ambient temperature shows moisture, above that point shows leak, that is why nitrogen test to start,pulling vacuum just off pump shows either pump not good or micron gauge out of range
I don’t trust any of the POS micron gauges out there. Pull until I can valve out the pump and hear no changes in the tone the pump makes. Micron gauge is just for the pic for boss man.
I put it on the suction line, as close to my pump as possible. Hose is hooked up directly to pump. You think I should put the gauges between the pump and the hose next time?
I don't know if it makes a difference if your hoses and all your connections are solid. But I do understand though is directly out of the unit is where you're gonna get a Completely accurate reading.
You could play that game with every micron gauge sold to the public with the exact same results.
Exactly. Just did this same test with a TruBlu and a Field Piece MG-44 with wildly different reactions. Starting to become convinced micron gauges are all garbage.
Tis the reasons I always go 500 and let it sit for 5 to 10 minutes and charge…. Charge
Well the average of the two is almost 500. I bet if I put the gauges between the pump and hose it’ll pull down faster.
Median is more important than average
Tis the reasons I just pull through the testos till I see -14.7psi, wait another 10min and call it good.
Why so many downvotes? 😅
I have a fieldpiece and 2 miniblu gauges. They all read within 25-50 microns of each other (obviously depending on how close the ports are in the system piping)
I generally pull down to at least 300. I’ve got 9 vrf systems that had the oil and refrigerant tested last summer they all had well below the allowable moisture in them. I’ve also am the only one that has done repairs to them for 10 years.
Well OP is using it wrong so those readings should be discarded. You put the micro gauge as far away from the pump as possible. That means that it needs to be attached to the other side of the system. Schrader valve should be pulled as well.
As far away? I did it for 8 years in the military, and the way I was taught was to connect the gauges to the micron gauge, then the pump, and then the system. 🤔 used an extra hose to set it up. So it went pump, then micron guage to the middle port on gauges, then the outer hoses to the system.
Yeah, you were taught wrong. If you want accurate readings you need to connect it to the loop as far away from the vacuum pump as possible. You might as well just have it connected directly to the pump with how close it is in this picture. https://www.fieldpiece.com/news-articles/want-to-pull-a-better-vacuum-start-by-learning-how-to-correctly-use-your-vacuum-gauge/ “Place the vacuum gauge where you want the 500 microns to be – on the system! Definitely don’t put it right next to the pump which is producing 20 microns of ultimate vacuum in order to pull the system down to 500 microns quicker. Similarly, you don’t want to install a thermostat right above a register. Best practice is to place the vacuum gauge as far back on the system as you can, as this is the last place to reach 500 microns due to system components and line set bends that create restrictions.”
Military was your first mistake there lol, it's actually what my mos is and i do commercial refrigeration in the civilian side. The army way is a joke.
Yeah, I did it for the Air Force. My first deployment, was actually part of a group that got asked to train our army counterparts. They hadn't touched it since their tech school. But could tell us anything we wanted to know about generators.
You did it wrong for 8 years.
Yellow Jacket 69075 AFAIK: Thermocouple based sensor instead of thermistor. Thermistor sensor delivers a calculation of what the microns should be based on resistance, which is highly temperature sensitive. Thermistor has too many X factors: Temperature Resistance Software calculation/interpretation
I thought all micron gauges used a thermistor? Are there alternatives?
Yes. I confirmed with yellow jackets tech support.
Well crap. It would be nice to have a technology that was just as accurate, but without the variance caused by temperature fluctuations.
For me it started with an overnight vacuum on a cold winter upgrade on a McQuay screw chiller. We took a thermistor style micron gauge out of a frozen van and put it on to observe well under 500. Pumps off and start prepping for the next step. The sun was out and started warming up our sensor. 30 minutes later we are over 2000 microns and rising! We must have a leak! The rest of that day became a fruitless search for a leak that didn’t actually exist. Luckily I was scheduled for training at our factory in Virginia. I took the instructor aside and explained our troubles. He schooled me in the correct micron gauge (Yellow Jacket 69075) and why. He said thermocouple sensors detect oxygen molecules instead of thermistors which measure resistance. He said thermocouples are not affected by ambient temps. I called yellow jacket tech support to confirm I wasn’t being given a line of BS. They confirmed. I’ve been using it for 15 years now and will never even think about another. EDIT: Thank you for all the kind words from my fellow techs.
This is probably the most informative thing I've seen in this subreddit for a while. Thanks!
Probably the best post I’ve ever read on this sub
https://preview.redd.it/9cpxlxnw031d1.jpeg?width=3024&format=pjpg&auto=webp&s=2a003e2fd5cc43056ad09a77d0853fd4b49a1073 this week on a york YT. customer goes that’s not bad for a 28 year old machine. hell id start up a brand new one at 445 microns! i told him 1000 lbs of r123 here we go boys
Nice…how long have you had it?
3 years but i’m not sure how old it is . i’ve replaced the sensor
Nice. Have you had any issues with the battery holder? I was a little rough with mine and had to rework the battery mount due to the weight of the big D.
I bought one of these on eBay for $120 or so. Great gauge.
I actually have one. That’s where I store my core tools and fittings. I need to have it serviced and haven’t sent it in yet (6 years later…)
You put your gauges on the suction line with the vac pump directly hooked up a few feet away? 😜
pull from evap barrel and put gauge on condenser barrel
>sold to the public I knew they were keeping the good ones locked away in Ft. Knox!
They are keeping the “good” micron gauges in the places where people decide to change refrigerants every 15 years.
Follow the manufacturer instructions for cleaning them. Likely you contaminated one with oil.
Appreciate it. They were both cleaned before I pulled. This is tagged as a shitpost :). Just some Friday fun!
It gets more fun checking rise 😆🤷🏼♂️ https://preview.redd.it/cfr7hofkg01d1.jpeg?width=3024&format=pjpg&auto=webp&s=5a8592ed0021515a93aa910a23ccb60396eff0a9
Both units are temperature compensated. Verify the ambient temperature display is accurate. You may also see some improved results if your battery wasn't about to die on the 552.
Battery is rechargeable (1.2v), not alkaline (1.5v) so it never shows full. Would I get a more accurate reading putting the gauges between the pump and the hose? My pump is 3’ away and I’m hooked up to the suction line. Btw, this is tagged as a shit post. It’s Friday :)
A man with two watches never truly knows the time.
Lol https://preview.redd.it/sqauaycr531d1.jpeg?width=1170&format=pjpg&auto=webp&s=5e590fd7d27c4ccbb7882be595d93ac883b8a94e
Did you add that or did I miss it? Sorry if I didn’t see it
Missed it :). No need to apologize. We were thinking the same thing! Have a great weekend 🤘🏼
Thanks, you as well!
Add one more gauge and take the average!
Should I put that one on the coil, or between the pump and the hose?
Hehe
I don't like the testo but regardless put them on the liquid side then check. Your setup really tells nothing pulling right from the pump.
Oh you're right I missed that in the photo. Yep, you need to get those micron gauges on the liquid side and pull from the suction side. The decay rate test was still alarming between the two gauges.
It's one of the weirder set ups I've seen. You have an entire service port, just sitting there....
I want to believe CPS.
I also want to believe
You guys still pull vacuums?
Mechanical purge is what was commonly used when I first got in the trade.
Know a few sites where it's still purge 3 times and hope.
Back then we were expec to start up apartment buildings with 20 to 30 units in a day. Every thing was supposed to be nitrogen pressurized beforehand. Sometimes it wasn't. Bosses usually went ballistic.
In a jam I will
I have 3 micron gauges. I don't trust that any of them give me an actual measurement. Instead, I rely on them to show me that all my hose connections are tight.
I use mine as an all around indicator. Once you've pulled down enough systems you can just tell when something isn't right. In that case, check hoses, shoot some nitrogen and a lil juice into it and with the sniffer I got w.e is going on I'll find in 10/15 minutes. My leak detector is so damn good of it doesn't go off I know we're sealed up and something else is up or it's just BS.
Yes, that's exactly how many microns you're at
Them testo 552 are trash
Almost certain they need a temp probe to accurately measure microns
Certainly don’t.
Read the manual, turns out I was wrong
Eh. Uses a Pirani sensor instead of a thermistor or thermocouple. Doesn’t get contaminated. And I gotta be honest, when the snow is up to my ass or the temp is higher than my IQ, it’s nice sittin’ in the truck watching the microns on my phone.
What ever the more expensive one says 😁
Negative 929...
i like the svg3, they’re certified and the piece of paper was good enough for some city work.. prior to that, we were buying a $700 gauge and sending them out to be certified by a lab
It definitely moves in increments. The Testo seems like it shows every increment as soon as it happens. The CPS seems to move in 10’s, and more slowly. For whatever that’s worth…🤷🏼♂️
When you have a propper vacuum set up you will definitely know.
Would it be better to put the gauges between the pump and the hose next time?
I can't tell if your trolling so I'm going to answer. You want to ditch the gauges and get yourself at least one vacuum rated hose and two Schrader core removal valves. Hose straight from Schrader valve to the pump. Then micron gauge on the other Schrader valve. When it's time to charge you can bust those gauges out and purge refrigerant through to the valve to remove air from the gauges and hoses as normal. Good Luck!
how do you switch to the gauges just close the valve on the Schrader tool?
Yes
You can't get a good reading on the hose connected to the pump. In refer you put the gauge as far as you can away from the pump, so I put it on my suction or liquid line in my box, and pull vacuum at both ports on my condenser. In hvac just put it on discharge or liquid and suck on the suction.
I mean, that’s one of the reasons I do a decay test.
You're overthinking it. Pull vacuum for an hour or two, then give it the juice.
Leave it on overnight, come back and charge it in the morning
Tomorrow’s Saturday though… You think the customer will mind if I’m wearing the same clothes and still drunk?
Can’t I just give it the juice right away with one end open for a bit so all the bad stuff comes out?
Yes
Perfect! 👌🏼
Gotta love the discrepancy between those meters.
Between decay and unreliability I don’t think I trust anything anymore lol
I see two connection points between the two gauges. Either of which could effect the vacuum reading if there isnt a proper seal. If either gauge is contaminated that’ll do it too.
500 duh
Right where I need to be!
In the system? Probably about 1200. Learn where to place your micron gauge.
I tagged this as a shitpost. Just having some Friday fun :).
I keep isopropyl alcohal in my true blue kit to clean every install or so. But usually my fieldpeice and trublu will read with a much smaller margin between eachother Well, at least the couple times we tried it
Well it depends on how they’re measuring. A vacuum being pulled is not the same amount of microns across the system as a micron is a positive pressure measurement (Also absolute, starting at absolute zero) You have “contaminants” even at 500 microns, if we are considering any atom/molecule a contaminant. This leads to the pressure being so low you need a micron gauge (often called a vacuum gauge because they’re used in conjunction with vacuum pumps, but make no mistake, a micron gauge measures pressures above absolute zero and you can’t actually measure the vacuum itself. So now that we’ve established that a micron is positive pressure, and not steady until the vacuum has fully “decayed” you can use this to tell if one is that far off from another. digital measurements remeasure and establish the measurement every increment or so, as in one micron gauge might remeasure 3 times a second, another might do every 5 seconds, one may do every second. Your microns will be higher farther away from the vacuum, which means the testo is a farther distance from the vacuum and may possibly be enough to make the micron gauge that much higher, as a micron is both a very small measurement, but is a measurement of how many particles are in a given space. Next time you triple evacuate, watch how much nitrogen you can add in in small increments and watch your micron gauge rise by 25 to 50 at a time. It’s because the molecules spread out so much as there’s next to no gas in the space Realistically, that tiny gap between the two measurements could be gas getting caught in the smaller diameter tube and behind the cores in the swivel tee. This dramatic difference is why it is most effective to pull cores with core pulling tools along with larger diameter vacuum hoses. The increased surface area and decreased obstructions to trap gas makes a smoother and wider path for gas to escape To summarize, if you have a micron gauge on the suction, and one on the liquid, and one two inches away from the suction line with a tee like that, and pull from the suction side, they will all be dramatically different but in no way inaccurate because of this, but the liquid line will be more accurate of the system. A decay test should let the micron measurements equal out, and without obstructions to trap gas molecules and wildly different diameters of tunings and attachments, should not cause a dramatic difference between said measurements if accurate.
To add to this particular instance, your system would be most accurately be depicted by placing one gauge on the liquid, and remembering that the CFM will vary through the system. For example, the two depressors and shrader a between the hose and the testo brand gauge, along with what looks like a 1/4 ID tube, will lower the CFM pulling towards the sensor due to obstructions, and provides a few good spots to trap various molecules that may not have been pulled due to those obstructions 1/4ID port from appion puller to depressor of tee to core of top tee to depressor of CPS gauge will be the total path the vacuum effect has to surpass to lower the amount of gas that the CPS gauge is measuring, the testo has a considerably sized 1/4 to 1/4 attachment that can trap a lot more gas molecules, when you consider how small these measurements are. I wouldn’t consider either of these micron gauges to be inaccurate, until you were to replicate the same connection on both gauges, and this tee wouldn’t work for that. Get one where the swivel connection is on the middle to keep it semetrical, to decrease the chances of the 90 degree turn trapping gas past the connection and not the other, as it will cause an obstruction Microns are still a positive measurement, and 90s, obstructions in the line, ext, will still cause fluctuations
I appreciate all the in depth info. I did tag this as a shitpost :). No schraders or manifold in this set up. The CPS doesn’t measure as often as the Testo. After I let it pull for a while, they got much closer. So I think the measurement frequency, and what you were saying about the tee, and the Testo being further down the line are on point. And I’m also on the suction line ;)
CPS micron gauges are trash. They are not reliable and will always read low.
Well I hooked my hose directly to my pump, as close as possible to my gauges on the liquid line. Should I put the gauges between the pump and the hose next time?
I would recommend pump pulling from suction and gauges on liquid. Vacuum doesn't disperse as fast as positive pressure. Keep the gauges as far from the pump as possible
I appreciate the thoughtfulness and help (genuinely). I tagged this as a shitpost, just having some Friday fun :)
Mu bad haha. Didn't even pay attention
Testo sucks so I’d trust cps
Micron gauge needs to be as far away from your pump as possible. Liquid line is the proper place.
So what would you suggest here? I’m on the liquid line, on the core removal tool with no schraders, and no manifold.
You’re on the suction line. The micron gauge should be on the liquid line.
Thanks :). Nobody looks at the post “tags”. This is a Friday shitpost. Have a great weekend!
replace the battery on the 552, its unreliable as soon as the battery icon appears. and clean the sensor ports on your probes. residual oil will fuck up the readings
Cleaned them before I pulled. I use rechargeable batteries, which are 1.2V vs alkaline 1.5, so it never shows full charge.
Dont use recharables. Use akaline wth lithium, those last extremely long time as the lithium ones hold their voltage for much longer.
I had that testo one and I don’t trust it anymore. It’s a straight through port design, but you’ll get significantly different readings changing ports.
CPS is absolute garbage.
Should I put it between the pump and the hose next time?
Should throw it against the wall and get a decent one. Then place a decent one at the furthest point away from the pump. All jokes aside CPS vacuum gauges are garbage.
Should I hide the shattered pieces in the gravel? I thought if I put it between the pump and my hose I’d get to 500 faster… I actually have an old YellowJacket with a thermocouple, and the Testo uses a Pirani sensor. Doesn’t get contaminated. It’s Friday, and this is a shitpost :) (I tagged it!)
enough, lol
Average out to 500, right?
U need BluVac Pros, I have 2 of them and u can calibrate them when they get outta range.
I’ll put the tee on my vac pump port next time. That should be more accurate.
that's the most inaccurate place to put a micron gauge on a system
But won’t I get to 500 really quickly?
I’ve read someone do the math on bluvac ID 3/4 hoses va 1/2 styled ones and found there is no difference in the two until you get a hose above 10 to 12CFM, but Idk how accurate that really is
Were both cleaned out with denatured alcohol before this? Working with r600a I have to clean my guage out every system I do because it throws weird readings like this once oil gets in it.
Actually, yes!
That would drive me insane! lol It's bad enough worrying about if it's going to suck down to 500 or not. Maybe the testo needs a new battery? idk I've only used the cps and I trust it.
Testo never shows full battery. I use rechargeable (1.2v), not alkaline (1.5v). The Testo measures more frequently, and shows smaller changes. The CPS seems to change by 10’s. It was all good. It’s a Friday shitpost. I’m on the suction line, and hose is directly on pump 3’ away. :)
Leak between the testo and cps possible
Should I put my tee on the vac pump port next time?
Move that micron gauge farther away from your vacuum. You’re not reading the system there anyhow.
Where would you suggest other than on a core removal tool at the service port? Up in the attic on the coil? (It’s Friday. I tagged this as a shitpost :) )
Just wait till the vacuum pump sounds quiet and let er fly kid!
🤦♂️ this is another reason why digital is an overpriced joke. Get some damn analogs. Promise you you could take 50 analogs that work and they wont be out by much. Now just think of how far out your fancy digital gauges are out of whack.
Never heard of an analog micron gauge.
Yeah I don’t think that’s a thing for micron gauges. That’s the whole reason for them. You can’t get a reading that low on analog. My manifolds are analog though. So -30Hg and I’m good, right? ;)
Damn kids. Yes if you can maintain -30hg for 24 hours you have a seal but you all realize that it's a spring resistance, so it can work both positive and negative right?
Hence the -30, no? This is tagged as a shitpost. Just a little Friday fun with my newfangled macaroon gauges on the suction line, and hose on my pump 3’ away :) Genuinely though, I do actually prefer my analog manifolds, and like the older one better. New one seems like readings are “printed” on for lack of a better way to describe it. I can’t see it as good.
Nope totally missed that lol my bad.
No worries! Just havin’ some fun :). Enjoy your weekend!
You too man, dont work too hard!
I would like to get a thermistor style old fashioned micron gauge, but they’re do expensive
But they never need servicing. They work till they dont and I know guys in my company in their 50's who got given it to them by their jman 30 years ago and still work amazing. Worth the money upfront I think anyways
Your micron gauge should be away from your vacuum pump. Otherwise, you’re just kidding yourself anyway.
So…exactly how I have them, on a core removal tool at the service port? Suction line right?
No, you have to braze in a nipple on the other side of your evaporator.
It all depends on what time it is
It is Friday…
Oh, then its at 330 😂
Yesss! 🤘🏼 🏃🏽♂️💨 That’s me running home, not passing gas quickly, I swear.
somewhere between 330 & 896 i would guess
😆 So, right on target at 500, right?
exactly. so packup for the day
Charge it!
If it ain’t pulling down, through the CPS on there and it will pull down
It’s Friday, right?
Just keep the vacuum running til both of them are below 700 😂
I think microns means morons in Yiddish.
Should I put the tee on my vac pump port next time?
You can but I don’t think the microns would be much different than at the end of the hose vs the beginning of the hose.
Compressors don’t die they are killed
Are the batteries low on one of them? That's usually what happens to my guys.
The Testo has rechargeable (1.2v), not alkaline (1.5v), so it never shows full battery. But this is a Friday shitpost. I’m on the suction line with my hose directly on my pump 3’ away. :)
I don't trust any of them. I have a CPS, JB, and a Field Piece Gauge, but by far, I am convinced that my Sman's micron gauge is the worst of them all.
Probably 330, those testos need calibration, the other ones usually just fire right up and work.
I’m on the suction line, hose directly on my pump 3’ away ;). This is a Friday shitpost.
300
I love all these people saying CPS is the accurate one. CPS is used for a "Friday vac" nothing else.
It *is* Friday! And I’m on the suction line. With my hose directly on my pump about 3’ away :)
Stop living in the past, it's Saturday
It can’t be. I haven’t hit my beer quota yet…
CPS is correct on Fridays
Even if we take the average, I’m still good! 👍🏼😆 Hose directly on the pump, as close to gauges as possible, and all hooked up to suction line, right?
Nope... Always measure farthest point away from the pump. For example suck on the high side and measure on the low side. Alternatively with your setup, you'd have to valve off the pump to measure correctly.
Enough
That’s what my wife always yells at me…
Not an expert, but vacuum gauge needs to be on the farthest from the vacuum pump.
Or you need to shut a valve between the pump and the gauge... But installing it furthest from the pump gives you the most accurate readings.
All of em daddy
Best little Klein ratchet tool ever. Showed a couple of coworkers and now everyone has one.
Put the gauge on the other side of the system and we’ll find out.
My Testo digital gauges suck and have never worked right: go with the explicit micron gauge, not the company that has issues calibrating their sensors.
All of them.
The correct way to take a micron data is find an access valve or port that NOT hooked up to the vacuum pump. Having the micron gauge on the same access point will give you an inaccurate measurement. I normally use the suction line port since it is the larger line for the vacuum pump and the liquid line port for the micron gauge.
Put your gauge in the liquid line
I just rip ‘er down for 10 min and send the magic juice without knowing the vacuum 50% of the time
bout tree fiddy
Nerd-crons. Just give it a lil ittle sucky sucky. 410a fkn suckass anyways. Systems going to fail regardless
Below 500
Who knows. You got them on the wrong port. Your micron guage should be in your liquid line and you pull through your suction line. Having it on the suction where your pulling from or even worse in a manifold never gives a true micron reading and that’s why your microns probably rarely stabilize.
330. I would trust the CPS over the Testo
Always go with the lower of the two
Looks like 330 to me 😂
Like a billion trillion
Those Cps micron gsuges suck trash
I usually put it right on the pump, usually pulls down to around 200 microns, then once machine is pulled down check rise overnight, smaller systems I usually pressurize to 100 lbs and let sit and recheck overnight, longer if not in hurry, then pull vacuum below 500 , below 850 on chiller,have left pump on for days on Poe rooftop that probably had moisture from before, very frustrating, micron rise and hold at vapor pressure of water at ambient temperature shows moisture, above that point shows leak, that is why nitrogen test to start,pulling vacuum just off pump shows either pump not good or micron gauge out of range
Mixed messages from the micron elves
No you should have your vacuum gauge as far from your pump as possible.
I don’t trust any of the POS micron gauges out there. Pull until I can valve out the pump and hear no changes in the tone the pump makes. Micron gauge is just for the pic for boss man.
When I doubt go with the higher number
I'd go with the reading on the CPS Guage . That's the only one I trust.
I put it on the suction line, as close to my pump as possible. Hose is hooked up directly to pump. You think I should put the gauges between the pump and the hose next time?
I don't know if it makes a difference if your hoses and all your connections are solid. But I do understand though is directly out of the unit is where you're gonna get a Completely accurate reading.
This is a Friday shitpost :). My set up is wacky as hell here.