Leaking Regulator

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David Kunkle
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Leaking Regulator

Post by David Kunkle »

I got a Prostar Platinum, H rated, regulator off ebay in excellent shape. I've realized it leaks out between the bottle and the low pressure side. Gauge says about 900 psi when I open the bottle. If I close the bottle, the gauge will slowly go to 0 over several days to a week. The gauge on the low pressure side never changes. Is this normal, or any suggestions on how to seal it? I'm guessing the leak is where the high pressure screws into the regulator body- it has Teflon tape on it. Seems like a waste of D2 every time I crack the bottle to do an experiment because there's usually plenty of pressure left for another time. Thanks.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
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Rich Feldman
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Re: Leaking Regulator

Post by Rich Feldman »

Have you tried soapy water? There are commercial leak detection fluids optimized for persistence of bubbles.
All models are wrong; some models are useful. -- George Box
David Kunkle
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Re: Leaking Regulator

Post by David Kunkle »

I'll try the soapy water next time there's any pressure in it. I think I was in denial thinking there probably isn't anything wrong with the regulator and that H will eventually find it's way out under pressure. Thanks. I have green threadlocker. Would that be any better than the Teflon tape on the threads now?
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
prestonbarrows
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Re: Leaking Regulator

Post by prestonbarrows »

If the bottle is closed and there are no leaks, a good regulator should stay pressurized for many months to a year type time frame. Just checked on a closed bottle that has moved from 1000 PSI to 300 PSI on the high pressure regulator gauge over 6 months of sitting.

One catch is if you have any plastic tubing or rubber o-rings between the low pressure regulator output and gas flow controller, hydrogen will permeate through over time. If you dont have the regulator set to 0PSI output, that slow leak will eventually empty the regulator over time even if there is not a macro-scale leak. Metal to metal seals are always best when possible.

If your regulator is empty after a few days, that is a fairly sizable leak and soapy water should show it to you.
Jerry Biehler
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Re: Leaking Regulator

Post by Jerry Biehler »

The pressure on the low side wont change, thats what a regulator is supposed to do. The leak could be on either side, the HP or LP. Back off the adjust knob all the way and see if it makes a difference how long it takes to bleed down.

If it is taking several days to a week to bleed down I would not worry about it. That is an insignificant amount of gas.
David Kunkle
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Re: Leaking Regulator

Post by David Kunkle »

Probably could've been a little more clear. With the bottle closed and the regulator knob closed, that 900 psi trapped between the 2 valves is what is disappearing in a few days. Every time I re-open the bottle, the high pressure gauge on the regulator reads about 5 psi lower than the previous time (905 psi before, now 900 this time). That much trapped D2 is more than plenty for whatever I'm doing at the moment- then the rest leaks out of the regulator after a few days. At that rate, I can crack the bottle open about 200 times before it'd be empty. Probably plenty of times to do whatever, but still a fairly big waste overall.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
Jerry Biehler
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Re: Leaking Regulator

Post by Jerry Biehler »

Chances are the leak is between the bottle and the regulator. Regulators get dropped and the male part can get dinged. Try tightening it some more.
David Kunkle
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Re: Leaking Regulator

Post by David Kunkle »

When I put it together, it seemed pretty tight- didn't want to damage anything. I tried tightening the regulator onto the bottle yesterday. It moved not even 1/8 turn with quite a bit of force and then it seemed to bottom out. So far, so good- seems to be holding a steady pressure. Thanks for the tip. After tightening the regulator, I did do the soapy water on all the threads and found nothing.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
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