Oxygen regulator still shows pressure after draining torch

[taydin]

After I finished using my OA set yesterday, I closed the acetylene valve and drained the torch. Both sides of the acetylene regulator showed zero pressure. Then I did the same for the Oxygen side, closed the valve and drained the torch. But the high pressure side of the O2 regulator shows 20bar pressure, while the low pressure side shows 0.

I first thought this is the same issue I had with the acetylene cylinder, where the valve was leaking. But this can't be the case, because then the input pressure would be 150bars. But it is lust 20 bar. Is the regulator dying?

[winchman]

I've seen that happen, and found I can get the tank side pressure down to zero by turning the regulator handle in while the torch valve is open, then out after the pressure is relieved.

I used to always release the pressure on the valves on my own O/A outfit, but the ones at the school seem to do just fine being left on overnight, or even for days at a time. I always close the tank valves when I'm trough for the day, but it's impossible to get the youngsters to do that all the time.

[MuellerNick]

I think this is kind of normal.
What I do, is close the tank, (almost never) drain the hose and close the valve behind the regulator*). If the high pressure rises a bit, I'm not concerned that much. Only if the high pressure shows the tank pressure, there is something wrong with the tank valve.

Just my opinion, I might be wrong.

*)
Not all regulators have that feature, my argon regulator (real flow through; the one with the ball) misses it.

Nick

[GKman]

I've never seen anyone who preforms the ritual described above putting their car on jack stands after driving. Isn't it the same principal?

[Your Old Dog]

I shut down the main tank valves, open the torch head valves until everything relaxes to 0. I then close the regulators down and then back out the screw until I know I've take some of the pressure off the rubber valve seal. My pressure regulators both stick if left fully out for several days. I've never witnessed any residual pressure on my tanks and I am always watching for it. Tanks that bleed are a little scary to me.

[Evan]

I have a Victor set that is now about 25 years old. Close the tanks, release all pressure and then close the torch valves. If it is to be left for a while then I back off the regulators. Either way there is zero pressure on both gauges and it stays that way.

[Boucher]

From your description it sounds like the high pressure gauge is not returning to zero. If it were the regulator there wouldn't there be pressure on the low pressure gauge?

[taydin]

From your description it sounds like the high pressure gauge is not returning to zero. If it were the regulator there wouldn't there be pressure on the low pressure gauge?

When draining the oxygen hoses, I have the cylinder valve shut, the regulator and torch valves wide open. What seemed odd is that it took a very long time for the hissing to stop. Maybe it didn't even stop and maybe it became so slow that it wasn't audible anymore. At this point, the low pressure side showed zero and the high pressure side was at 20 bar.

Another weird observation (didn't happen before) is that when I cranked up the regulator valve, I clicking and rattling sounds from the regulator. Can it be that the high pressure side has lost its sensitivity, where it properly reduces high pressure O2, but stays shut if the pressure drops below a certain threshold?

[taydin]

I've never seen anyone who preforms the ritual described above putting their car on jack stands after driving. Isn't it the same principal?

Not sure I understand this

Are you saying I shouldn't bother relesing the pressure? Just shut off the tank, the regulator and torch valves and be done with it?

[winchman]

In my mind, shutting the tank valves is a safety step that should be done whenever the rig won't be used for a while or whenever it'll be unattended.

I used to think relieving the pressure on the regulator and torch would prolong their life, but that appears to be unnecessary based on what I've seen at the school.

The car on jack stands analogy was lost on me, too.