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Originally Posted by vzenuh

I have read over all the posts but I feel the need to post my two cents.

A micron gauge is essential for any tech. I went to a scotsman class and a true class on the same day. Both their reps asked for a show of hands of who used a micron gauge. I was amazed to see that only 50 percent of the class raised their hands.

The first tech I ever rode with had a micron gauge. A supco I believe. I never seen him use it. Needless to say the first time I had to borrow his truck on a weekend call I went to use the gauge. It didn't even have batteries in it.

After he quit, I put my tools in the truck and hit the road. I ended up going to one of his previous calls on a walkin cooler. System was very, very low on refrigerant. Only about 5psi in the system. I hit it with nitrogen and the whistling noise was apperent. The leak was in the condensor on the top u joint. He didn't even cut away the surrounding steel. He heat it up and threw what looked to be about two sticks of 15 percent on it. I caught hell cutting the steel away and trying to grind down the solder with a cutoff wheel. I did get the leak fixed and haven't heard from them since.

If he would have used his micron gauge he would have know that the leak wasn't fixed.

Hell, nitrogen would have told him the same thing.

Vzenuh, My first question was about that Tech's practices, I'm "cheering" you, for what You did.

Get a blue vac, practice some self control watching the gauge as it will wigg you the first few times if your not used to it. From there follow best practices but pay attention to your vac times and mentally document that along with how well you held up to those "best practices." When its 105 and people are flipping out for cold air, shortcuts happen wether we like it or not. But keeping a mental log will validate everything for you, in the field and with your own eyes, BUT with micron readings to relate too.

Rambling over, get a blue van

Originally Posted by DirtyHamilton

Always use a micron gauge. I love JBs. It's going to let you know if you have moisture in the system & if it's in a good vac.
I've met a lot of guys that don't think twice about micron gauges or even bleeding your lines before hooking up to a system with your manifold pressure gauges...Do things the right & recommended way and you'll be better than a lot of new techs out in the field today.

For me, the JB DV-40 had too much buffering. I had become accustom to the wiggling needle of a Hastings/JB gage years ago indicating a tiny leak. The DV-40 just as too much buffering and doesn't give the same indication. On the other hand, the Bluvac has the exact right amount of buffering and shows a micro leak the same way with an unstable digital output. The Bluvac also gives a pretty good moisture indication - and their top of the line tool even directly shows dehydration on your phone.

Originally Posted by vzenuh

I have read over all the posts but I feel the need to post my two cents.

A micron gauge is essential for any tech. I went to a scotsman class and a true class on the same day. Both their reps asked for a show of hands of who used a micron gauge. I was amazed to see that only 50 percent of the class raised their hands.

The first tech I ever rode with had a micron gauge. A supco I believe. I never seen him use it. Needless to say the first time I had to borrow his truck on a weekend call I went to use the gauge. It didn't even have batteries in it.

After he quit, I put my tools in the truck and hit the road. I ended up going to one of his previous calls on a walkin cooler. System was very, very low on refrigerant. Only about 5psi in the system. I hit it with nitrogen and the whistling noise was apperent. The leak was in the condensor on the top u joint. He didn't even cut away the surrounding steel. He heat it up and threw what looked to be about two sticks of 15 percent on it. I caught hell cutting the steel away and trying to grind down the solder with a cutoff wheel. I did get the leak fixed and haven't heard from them since.

If he would have used his micron gauge he would have know that the leak wasn't fixed.

Hell, nitrogen would have told him the same thing.

A leak of that kind wasn't evident by reading the gauges?

Always use a micron gauge. I love JBs. It's going to let you know if you have moisture in the system & if it's in a good vac.
I've met a lot of guys that don't think twice about micron gauges or even bleeding your lines before hooking up to a system with your manifold pressure gauges...Do things the right & recommended way and you'll be better than a lot of new techs out in the field today.

No you're 100% correct about TIME. Especially if you have a low cfm pump. I just mean I didn't have a micron gage at the time. But yeah Now I make sure my microns are low before finishing up.

I never pull a vacuum on TIME. The micron gage tells me if the vacuum is complete, not my watch.

You are correct about monitoring the condition and ability of vacuum pumps. A pump that cannot pull below 200 microns is useless and there is only one way to know.

Too bad we lost posts from late last year regarding vacuum, there were some very good ones.

mpw;1241353
You can always buy the SMAN360 3 port Digital gauges that have a micron gauge on it I feel like the digitals alone are over priced (But that's me) Also they have sub cooling and super heat clamps which I always test when reading pressures (Some will disagree but to each their own). They are a little pricy but they are worth it in my opinion.Anyway always test Microns when vacuuming. If I don't have one on me. I'll pull the unit for over an hour and a half Granted my Pull-Vac is brand new. Still makes me sketched out not using the proper tools. Also it makes it easier to test for leaks. If they start climbing either your hoses aren't tight or you get to do some searching. Also always make sure your oil is clean and at the right level I can't count how many times I've used someone's vac at work and it was just filthy inside. That's not smart... Its best to take a little longer to fix the problem rather than look non professional and have to come back, Or worse another tech comes and fixes your mistakes.

I have system past pressure test but didnt pass vacuum test,and sure not find a very tiny leak!micron gauge is a must have tools!

Originally Posted by kdb4

Thanks for the confirmation, I have spent a lot of time reading the forum to figure things out and never ran across this. I bought the full Appion Megaflow kit with the 20 micron rated manifold, the 1/2 inch vacuum hoses, etc. It works great, I'm always down around 350 microns on an evac, but I was always unhappy about how I had to hook up the micron gauge to the CRT service port.

I had been pulling the schrader out of the CRT service port and using a short 4" rubber hose, it didn't have a valve depressor in it, its all I could come up with. I did have the JB D10244 2" sae swivel adapter but there usually wasn't room to fit it on the CRT and get my micron gauge on it as well, as it didn't bend.

It would be nice if this was included in the Appion Megaflow kit. True Tech Tools includes it in theirs.

TruTech is a supplier while Appion is a mfg. Trutech puts kits together from different manufacturers ...see why now?

Thanks for the confirmation, I have spent a lot of time reading the forum to figure things out and never ran across this. I bought the full Appion Megaflow kit with the 20 micron rated manifold, the 1/2 inch vacuum hoses, etc. It works great, I'm always down around 350 microns on an evac, but I was always unhappy about how I had to hook up the micron gauge to the CRT service port.

I had been pulling the schrader out of the CRT service port and using a short 4" rubber hose, it didn't have a valve depressor in it, its all I could come up with. I did have the JB D10244 2" sae swivel adapter but there usually wasn't room to fit it on the CRT and get my micron gauge on it as well, as it didn't bend.

It would be nice if this was included in the Appion Megaflow kit. True Tech Tools includes it in theirs.

Originally Posted by kdb4

I found this, saw it being used in the true tech tools youtube video. Seems like the perfect adapter for the micron gauge.

Micron Gauge Coupler by yellow Jacket 69071

http://www.trutechtools.com/Vacuum-G...er_p_1989.html

Heck, that's standard equipment in anybodies vac kit these days.

micron gage to CRT coupler

Originally Posted by stomper56

JB D10244 Deep vacuum 1/4 sae swivel coupler
Just picked up two myself, the rubber gasket is smaller then normal though so it looks like it might have to be babied.
If using for vacuum i reccomend some Nylog on the gaskets.

I found this, saw it being used in the true tech tools youtube video. Seems like the perfect adapter for the micron gauge.

Micron Gauge Coupler by yellow Jacket 69071

http://www.trutechtools.com/Vacuum-G...er_p_1989.html

micron

I have read over all the posts but I feel the need to post my two cents.

A micron gauge is essential for any tech. I went to a scotsman class and a true class on the same day. Both their reps asked for a show of hands of who used a micron gauge. I was amazed to see that only 50 percent of the class raised their hands.

The first tech I ever rode with had a micron gauge. A supco I believe. I never seen him use it. Needless to say the first time I had to borrow his truck on a weekend call I went to use the gauge. It didn't even have batteries in it.

After he quit, I put my tools in the truck and hit the road. I ended up going to one of his previous calls on a walkin cooler. System was very, very low on refrigerant. Only about 5psi in the system. I hit it with nitrogen and the whistling noise was apperent. The leak was in the condensor on the top u joint. He didn't even cut away the surrounding steel. He heat it up and threw what looked to be about two sticks of 15 percent on it. I caught hell cutting the steel away and trying to grind down the solder with a cutoff wheel. I did get the leak fixed and haven't heard from them since.

If he would have used his micron gauge he would have know that the leak wasn't fixed.

Hell, nitrogen would have told him the same thing.

i let it stand as long as i can, 24 hrs is a good rule, but if you have longer itll make you feel better. 1500 ton trane B left at 300 microns for 1 month while waiting on starter work, left me real confident. on an emergency you wont have as long.

micron gauges are like leak detectors, the are only good if you have one you trust. also the prob i have had in past cones from over tightening the flare cap that has copper washer instead of rubber seal, it smashes the top of the flare in.

A correction to my post #151 experiment, in the second paragraph when I said I closed the C&D to pull a vacuum from the 3/8 line only, that was not the C&D valve that I closed, it was the ball valve on the short hose to the 7/8 line. Closing the C&D would have isolated everything (both gauges and the service lines) from the vacuum pump. I did it right, just described it incorrectly, and I can't edit the post now. If you were trying to follow what I did, it would have been confusing.

Originally Posted by kdb4

It convinced me its better to pull a vacuum from both sides, or at least check it a few more times to see if that always happens.

Good experiment. I have been wondering what would happen in that case.

Just thinking about it though, I had concluded the same as you. You can't pull a vacuum through a metering device.

The pressure difference is too small. 1000 microns is only 1 mm of mercury.

Always pull from both sides

Since I have a sman3 and a VG64, I thought I'd try an experiment. I put the VG64 on the 3/8 liquid line with a short 6" ball valve hose, then to the VG64, then to the sman3 high side with a 3' hose (VG64 has two male connectors). I connected an identical short ball valve hose to the 7/8 suction line, then to a C&D core removal tool with a side port, and then through 12" stainless hose to the vacuum pump JB DV-142n, and connected the side port of the CRT (valve core removed) through a 4" hose to the center tap of the sman3. The low side of the sman3 was capped and valved off. A lot of hoses I know, but I wanted both gauges hooked up.

I pulled the vacuum and watched the two gauges. I had closed the high side of the sman3 so the VG64 only read from the 3/8 line, sman3 only read from the 7/8 line that had the vacuum pump on it. After a while the sman3 was at 500 microns, but the VG64 was still reading atmosphere, then slowly it started to drop from 9000 microns. I shut off the short hose ball valve on both sides (now the gauges are disconnected from the service lines), opened the sman3 high side, pump is still running and both gauges dropped readily to 150 microns. I know the VG64 tracks pretty close to the sman3, I've tried that before. Put it back like it was and finaly got 3/8 line down to 2750 microns (VG64 changes 250 at a time at that range). Probably a half hour of this and I'm out of patience so I finally opened the high side sman3, closed the C&D, and pulled the vacuum from the 3/8 only for a while to get it down, then both open to 475 microns, then blank off at the vacuum pump and let it sit for 5 minutes and the sman3 eventually rose 5 microns, the VG64 didn't change (changes 5 at a time at that range). I thought all the hoses would have leaked more than that but it didn't read on the gauges.

This had a 4-ton copeland scroll compressor, and a piston metering device on the coil, and the service line was about 47 feet. It didn't do what I expected it to, I thought the 3/8 would be a little slower dropping when I pulled the vacuum from the 7/8 side, but I didn't expect it to be that slow. I"m thinking that the scroll probably doesn't pass much flow when it is off (just guessing) and the only other way over to the 3/8 line was through the capilary tubes in the coil. Seeing how much a small hose can restrict a vacuum, I figure those 1/8" capilary tubes were not helping much. It convinced me its better to pull a vacuum from both sides, or at least check it a few more times to see if that always happens.