Bad regulator?

[ej4]

Do I have a bad regulator or empty tank...?

I got used oxyacetylene tanks with some older regulators (prostar?).

When I put the oxy regulator on, it registers about 750psi on the high pressure side. I adjust the regulator to around 20psi. When I open up the valve on the torch the pressure goes to zero, and oxy comes out but trickles to a stop. If I shut off the torch valve and wait a few, pressure will build back up again to 20psi.


Is this a regulator that needs replacing? or do I need to refill the tank (how low should I be able to reasonably go before refilling)?

I took a welding class but other than a demonstration, we didn't have to do much with the actual tanks.

Thanks-

[urch55]

EJ.
It might be your regulator. Turn the line pressure to 40 psi and see what happens. I can use all my oxygen up to the point I can't cut steel with it.
Also try adjusting your regulator while your torch valves are open. Your acetylene should never be any more than 10-15psi line pressure for most torches..

[GilaSlim]

How far did you open the oxy cylinder valve? Oxy valves should be opened all the way to prevent leaking. If you just opened it a little bit, it may be restricting flow from cylinder to regulator.

Also, check the regulator inlet for a filter. There should be a clean, metallic porous filter inside the inlet. If the filter is dirty and plugged up, replace it with a clean one.

Your acetylene cylinder valve should never be opened more than about 3/4 turn. It does not need to be opened all the way to seal.

[ej4]

Thanks.

The oxy tank valve is fully open. I'll try to up the pressure to 40psi and see if that does anything.

Not sure about any filter on the inlet...will have to look. What's it look like and how is it removed? iirc, there is what looks like a silver wire bundles around the outer circumference of the inlet, but it didn't look like something that coule be taken out. Will look again.

-ej

(thanks for the reminder on the acetylene - tank valve is open 1/2 to 3/4 turns. In class we were told to use 4-5psi on acetylene and 8-10 on oxy.)

[Roger]

Your problem description indicates flow restriction in regulator or cylinder valve.
Standing to side of valve outlet with no regulator installed slowly crack open valve to get restricted flow then close valve. I do this before connecting regulator to blow crud out of valve then connect regulator. It will also indicate cylinder valve flow restriction.

As stated in prior post could be plugged inlet filter but I have seen terribly corroded brass sintered metal inlet filters on scuba regulators with lots of internal corrosion that were used that way. One diver I had to look at is regulator filter for green or white deposits indicating this problem and fix it because he would use it until it wouldn't work. Just a little salt water would cause the corrosion. Stainless Steel filters used now don't turn green. I have never removed a cone filters. Ones I have seen are friction fit. Push out from rear or use a small O2 clean tap (used for cutting female threads) to pull cone filter out. Maybe pry out cone filter with a O2 clean scribe. Then must replace with new cone filter.

New OPD propane cylinders valves have flow fuse that restricts flow if you open valve too fast.

Most common regulator failure is free flow or gas leaking by because regulator valves are held open by hand set or pre-set spring pressure until regulated air pressure closes the regulator at set pressure. Exception to this is a dome loaded regulator that uses air pressure to hold regulator open until set regulated pressure is reached but not used for welding regulators. Leaking diaphragm on dome loaded regulator no air spring to to open regulator valve. Common spring loaded regulator with leaking diaphragm you would hear leak and leak could be big enough to prevent regulating gas pressure.

http://www.westernenterprises.com/enterprises/PDFS/wi20.pdf

[ej4]

Thanks, Roger.

Yeah, I think it's a regulator issue. I played with it some last night and saw similar behavior at higher pressures, and also heard a small hissing in the regulator when the torch valve was closed.

Unfortunately, I don't have a spare to test out the theory. I may have to bite the bullet and get a new setup; buying a single regulator isn't much less than a full kit, and I don't have the expertise to pull this stuff apart to clean or fix it; I'll leave that to the experts. Being an offbrand, I'm guessing the regulators aren't quality enough to have them rebuilt.

In any event, from feedback here, it sounds like my oxy tank should have enough gas in it, and doesn't require refilling, and the issue is in my equipment. I'll go from there.

Thanks for the help, folks!

[Roger]

Take your regulator to welding or gas supply dealer ask who fixes them locally and price. If parts are available it can be fixed. Much cheaper than buying new. Imported regulator is throw away item without repair parts. Can still get parts for many old US made regulators you hardly see any more.

[usmcpop]

Prostar is a Praxair brand, possibly a re badged Victor.