Co2 Pressure test

[jeff32]

I have read that you can pressure test a system with CO2, but have always been taught to only use dry nitrogen. Does anyone know of a reason why CO2 cannot be used?

[bowman]

DO NOT use...i repeat DO NOT use co2 to pressurize any refrigeration system. The reason for this is becouse co2 has a high moisture content, which will be very very bad for your system if you add co2 to it. That is why dry nitrogen is used. You will be having moisute problems in the least for the next 100 years......Eric

[Senior Tech]

You read wrong...or someone wrote wrong...no co2 for pressure testing period.

[johnl45]

We use it all the time no problems.

[Senior Tech]

Originally posted by johnl45
We use it all the time no problems.

You mean no problems yet, puts moisture in system, guaranteed.

[johnl45]

Originally posted by senior tech

Originally posted by johnl45
We use it all the time no problems.

You mean no problems yet, puts moisture in system, guaranteed.

No I mean no problems ever on systems that we have service for years!

[Yuma]

Dry nitrogen is the best and preferred item to put into a system other the refrigerant.
Now, I did work once with an elder statesman tech that said CO-2 could be used in a pinch. But you do need to take added care. Problems can (and more often do) show up.

As for absolute NO's in this trade, it keeps changing all the time. Note the thread on mixing some of the gasses.

But the best to use is a dry product.

Yuma,

[midhvac]

I've only done it once but it was on an a/c system, not a refrigeration system. I was trying to open a clogged cap tube, and purged it with dry nitrogen afterwards. That was 20 years ago, and I haven't had the inclination to do it since.

Conventional wisdom is that, as the others said, the moisture content's too high, but also keep in mind that the pressures are anywhere up to 2,000 psi on a hot day!!! Which brings to mind some problems with what you're going to use to get the CO2 into the system.

Just blowing out condensers with a refrigerant hose (with the fitting cut off one end), I've had the hose blow a big chewing gum bubble in the middle and pop

Couldn't hear much for a few minutes.

Then I got "smart" (NOT!) and flared a piece of 1/4" copper, and it froze to my forearm while blowing out a condenser

[bryan l]

Here is a link to a three page discousion on this topic http://hvac-talk.com/vbb/showthread.php?threadid=35599

If you scroll down page one and read the third from last on that page there will be a link. The link will show you what is in CO2. The whole topic is a good read.

[condenseddave]

How about pure Oxygen? I hear that's always an exciting leak test...

[hvacguy1179]

acetaline i hear works well to i like smoke while using it just look for the flame and you found your leak

[snipe70e]

Originally posted by condenseddave
How about pure Oxygen? I hear that's always an exciting leak test...

Dave,
Sometimes you make the hair on the back of my neck stand on edge. When my heart slows down I realise you are just kidding.
Len

[bryan l]

Pure Oxygen. Yah I can just see that now

WHOMP
(as all the pictures on the wall for a 5 block radius fall off the wall)

"Hey John I found that leak we were looking for"