No but I sure have an opinion about the Thermal Eng 14571 analog gauge. I love it. It's accurate, easy to use and I really like to see the progress I'm making all the way from atmosphere down to the <500 micron level.
Originally Posted by AirTechMech
I also have a Fieldpiece digital micron gauge and it's going on Ebay pretty soon. The two units match very closely but the Fieldpiece leaves me blind with what's happening until I'm below 2000 microns.
I Aways use one
I would not charge without using a micron gauge first.
I used to build chillers and you could pull the gauges down to full vacuum even with a small leak in the system but the micron gauges would show it up very clearly. i use this example because on older systems you could have mosture in the system but on a brand new chiller it should be dry.
On the other side i have seen loads of people charge vehicle a/c systems without even pulling a vacuum and it still appeared to work to the customer, not d.i.y.ers either.
When pulling a vacuum do you use your standard charging hoses or do you use flexible steel vacuum lines? I been reading on how rubber hoses are permeable and not good for vacuum
Mark could you repost the picture its gone (broken link)
Also I use the Yellowjacket Core removel tool. what to you find to be the best out there.
If you help others then you are a Success
what sucks for home owners is barely any installers use one so from day one the systems going down hill
Originally Posted by BobbyBJr
Last edited by ryand; 09-21-2007 at 11:44 PM.
I have always used a micron gauge but just recently bought a Y.J. two valve manifold with the 3/8th to 1/4 hoses and schrader core removers and it is one of the best investments i have made! not only did it pump down fast i pulled a residential 4 ton system down to 140 microns and held it at 168. I dont know about you guys but i have never gotten lower than 400 microns. the Y.J. part number for the kit is 93865 and its worth its weight in gold
I have also had difficulty getting and maintaining 500 microns and below.
That started to change once I ditched the standard 3/8 charging/vacuum hose for one of those Goodyear Galaxy barrier hoses.
I also noticed a change when I switched to Refco charging hoses with the quick connects on them. The new Refco manifold may have helped, too.
I suspect that the only way to go is the stainless hoses.... or, all barrier style hoses.
Then I tried the triple evacuation method. There was plenty of time to let 10 psig of nitrogen sit in the system for 20 minutes a cycle, and that really helped to bring the micron levels down quickly.
*That* did the trick.
After actually doing it and watching the micron gauge, I don't believe there is a way to achieve and maintain low micron levels unless the triple evacuation method is used.
On the opposite end of the spectrum, I am aware of several big name outfits that don't even use a vacuum pump. Purge and go- only 2 hours per install...
Proper Prior Planning Prevents Piss Poor Performance
"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey. It's unwise to pay too little.
When you pay too much, you lose a little money -- that is all. When you pay too little, you may lose everything, because the thing you bought was incapable of doing the thing it was bought to do.
The common law of business balance prohibits paying a little and getting a lot -- it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you will have enough to pay for something better."
To purge aircraft liquid oxygen systems we would run nitrogen through a 120 vac operated heater. One of those being used to sweep a wet system could have possibilities.
Found a photo of one of those purge kits at Carelton Technologies. The lox fill nozzle would have to be removed and a 5/16ths to 1/4 inch adapter fitting and hose would have to be installed but this could have possibilities on extremely wet systems.
A micron gauge is one of the tools that I don't get unless I buy it. And since all my work is done for my employer (the state) there's really no incentive for me to buy one myself. Maybe I can talk the boss into buying one the next time he gets on a tool kick. I also need a digital scale, I'm stuck with the "shake the jug" method for now.
Since I don't have a micron gauge I normally try to pull down to 29 and if I'm in a hurry it's 29 and no vapor coming out of the pump. If I have some time to spare I'll pull on it overnight, shut it off in the morning, and see if it holds at least 27/28 for two hours. If so, then it's fill 'er up time.
Anybody like to donate to higher education? We "do it for the kids" is the party line around here.
I am very familiar with the shake the jug charging method, as well as the touch and feel micron gauge.
I started using a micron gauge and a digital scale when I went into commercial. I do a residential job every once in a while, and I like using the scale and the gauge, it takes the guess work out. I just bought the YJ digital micron gauge, I had the supco before and lost it, because it is too small. I was told that the YJ is the best out right now.
I STARTED WITH NOTHING, AND I STILL HAVE MOST OF IT!
Confession: I was a "beer can cold" guy for many many years.Never used a micron gauge.We got into the higher eff. units a few years ago, and with the TXV's it was impossible to get the charge right.So I bought the gauge and swear by the thing now.the question i have is: How long on average does it take you guys to pull 500microns on lets say a new install 3.5ton split with 50ft of refer(7/8-3/8) just the coil and refer of course without opening the system up yet?????Iv'e had it take several hrs, and question the vac. pump I use.Its an old Robinair 6cfm VacuMaster pump.When I isolate the pump and hoses all is tight and good.I also will do the triple purge with Nitro. and that seems to help the larger systems pull down faster.Are the "new and improved" pumps any faster/better?
Don't mean to hijack this thread, it just seemed like it was going in the same direction..
Last edited by acemechanical; 09-22-2007 at 03:17 PM.
That sounds about right. Some take longer then others. Change the oil in you vac after each use and thet will help.
I STARTED WITH NOTHING, AND I STILL HAVE MOST OF IT!