pulling a vacuum

[DKPAT]

I am reading posts about micron gauges to get an idea which one to buy and thought I would put in my 2 cents as to why they are necessary.
I am still new at HVAC and recently put a small system together in the shop. I pressure tested the system and it seemed to hold the pressure so I pulled a vacuum. I could not get the vacuum gauge to hit 500um. I found a verrrry small leak in a flare joint that needed tightening. I then got down to 500um in a couple of minutes.
In my opinion if you're not using a micron gauge you don’t care about the quality of your work.

[clarkkent]

Vacuum rated core removal tools
http://www.appioninc.com/products/vctfeatures.html

Anybody used them yet and how do they hold up?

[MechAcc]

Vacuum rated core removal tools
http://www.appioninc.com/products/vctfeatures.html

Anybody used them yet and how do they hold up?

Yes I do. They hold up well and the bore through the core remover has a larger opening than C&D's, Yellow Jackets or Cliplights. The JB's have a larger bore but the flare end has the sharpness of a hole punch and will chew up your hose gaskets in short order.


Appion on left JB on the right.

The Appion has double O-rings in the coupler and for the lever shaft for a good seal.

Worth the price? Yes they are.

[itsiceman]

Mech if you look at all J/B hoses and fittings designed specifically for pulling vacuum they use O-Rings and not gaskets.
I believe the J/B VCRT's are designed to work with O-Rings.
I am in the process of switching all my vacuum equipment over to O-Ring equipped

[MechAcc]

Mech if you look at all J/B hoses and fittings designed specifically for pulling vacuum they use O-Rings and not gaskets.
I believe the J/B VCRT's are designed to work with O-Rings.
I am in the process of switching all my vacuum equipment over to O-Ring equipped

Was not aware of that. Thanks.

[biggi]

so how do you find a leak with a vacuum? and what are some other things to look for when you have a vacuum pulled? Thanks every one for all the input.

[qwerty hvac]

Leak test, then vacuum.

[mountainman88]

Remember, the micron guage can malfunction too. I've seen some that read 300 microns when I know there's a leak. Electronic gizmos can be unreliable... got a computer? Still, it's very important. Change the oil in your vacuum pump after every job, make sure seals are good, especially low loss fittings that have had 410a pressures on them or are just old. If you still think it's your vacuum pump, check it with another micron guage to be sure. Also, if you have moisture in a system that doesn't leak, it can take a long time. The water has to boil out (water will boil at 0 degrees in a complete vacuum) which causes expansion then the vapor must be removed. Keep your copper clean and dry.

I once spent 6 hours looking for a leak that turned out to be in my manifold set. Boy was I mad

[greenwoodservice]

love the apion mega flow kit. the time savings in amazing! too much $$ though. but then ain't it all

[pushpipe]

my digital gauge set has microns right on it, and i us it everytime the vac is on. mine starts at 0 and goes negative from there. like to see at least -600 the best i've ever seen was -755.

[thes]

Leak test, then vacuum.

agreed!!!!!!!!!!!!!!

[JumpSteady]

I've been using a Yellow Jacket 69080 Digital LCD Vacuum Gauge. It has bars that go from 500 to 750 to 1000, etc. I like it. It seems to work well enough.

[MechAcc]

I've been using a Yellow Jacket 69080 Digital LCD Vacuum Gauge. It has bars that go from 500 to 750 to 1000, etc. I like it. It seems to work well enough.

Yellow Jacket only lists the accuracy of their 69075. Which is +/- 20% and it is a digital readout. They do not list the accuracy of the 69080. Have you checked it against other electronic vacuum gauges?

[boat racer]

After you have done your best pressure leak test, a good vacuum gage can be the final test of system integrity.

Static vacuum and not running vacuum is the real test.

[icehouse]

Not that I have a clue about things.

Amprobe Ultrasonic Leak Detector, TMULD-300


In areas where leaking gases are not sufficiently pressurized, there is no ultrasonic sound for detection. The area can be pressurized with the ultrasonic sound waves created by Amprobe's UT-300 Ultrasonic Transmitter. This will allow the detection of cracks which would not normally be possible. Locates arcing in an electrical system. Useful in finding the ends of buried PVC pipes.

[boat racer]

I have found ultra sonic devices helpful at times when other methods were failing, but I've had less success with it than with refrigerant detectors in general. The ultrasonic transmitter is not useful for our work, its for structural cracks like roofs, etc. I've never tried it in an open pipe, but I guess it would work well. I've had a receiver and transmitter on my truck for almost 20 years, but rarely use them. I don't know if you can rig up the transmitter to spray sound waves into a pipe smaller than the 3/4" horn on the transmitter either ... a pain in the butt if you had to anyway.

I even accidentally discovered that soap enhances the chances of finding a leak with ultra sound ... the repeated forming and popping of bubbles picks up better than a dry stream of gas. Ultra sound device also showed me that pin holes take time to ramp up ... it might be 5 minutes after you apply pressure that the pin hole is really flowing. Be patient and retest.

The down side of ultrasonic ... extremely directional. You can be directly adjacent to a leak, but not pointing in the direction of the sound propagation, and miss it entirely. I do not know of another detection method that is as picky about pointing straight in at the leak.

[JumpSteady]

Yellow Jacket only lists the accuracy of their 69075. Which is +/- 20% and it is a digital readout. They do not list the accuracy of the 69080. Have you checked it against other electronic vacuum gauges?

No. I only have one, don't have anything to compare it to. It seems to work as it should.

[mafunk]

My new setup (which I haven't used through a full vac yet) is JB Platinum 7CFM vac pump (shop supplied), two YJ vac hoses (3/8 hose with 1/4 fittings on one end) straight off of pump (has 3/8 - 3/8 - 1/4 port, why not a 1/2" on a 7CFM pump is unknown to me) to two 1/4" YJ core removal tools (with side port). Off of one of the side ports is a YJ ball valve shut off connected to a JB DV220 micron gauge.

I work primarily in residential service and install, but do commercial as well.

I have only fully used this setup on a test, on a 26 lb reclaim bottle, but this vs my old setup (1/4" charging hoses off of a vac pump tree, micron gauge at top of tree) was a world of difference. 8m 45s to 200 micron with new, 50 minutes to get to 277 with old (had to break it down to head to a job). We'll see real results tomorrow (service valve on a 20lb 5 ton system.

As far as the DV220, I dislike them. They are very slow to read, and I've been through 2 of them, last one only lasted 11 months. both of them ended up that I could take them completely out of the system and they'd read a vac for minutes before they'd start to show a change. This last one (a few weeks ago), I wanted the shop to get me a BluVac, but cheaper cost and availability (needed it then and there) won. I'll be buying myself a BluVac sometime in the near future.

[itsiceman]

The J/B Super7 I saw had 1/2, 3/8 and 1/4 but FWIW you can pull 7cfm with that pump thru one 1/2" hose with 3/8 and 1/4 fittings on either end.

[itsiceman]

To be clear you can pull 7 with your platinum and one 1/2 hose