Will leaving the gas flow open cause problems?

[e-z-ride.com]

I normally turn off the gas flow of my tank after each use of my HH175, but from time to time I find myself forgetting to turn it off for the night.

If I continue to keep forgetting, will I ruin the built in valves of the HH175 ? Is there anything else I will prematurely ruin?

ALso, when I turn my gas flow open, should I turn the gas flow completely open (6-7 turns of the valve) or should I turn it just enough to get the pressure gauge to read ? Assuming one way is worse than the other...WHat bad things will happen if I turn the valve partially open or fully open ?

[Dan]

You want to open the valve all the way, because the vavle has a seat at the bottom and top of its travel. If you open it part way there is a chance that you can start loosing your shielding gas through the end of the valve.

When your done welding for the day, you should shut the gas off at the tank. Then purge the machine. Then back off your regulator so that there is no presssure against the diaphram. By doing this you will extend the life of your regulator. Before I started working at my current job the guys in the shop would just turn the valve off on the tank and walk away, because of this we now have regulators that are stuck at 20 cfh. They will not adjust up or down , but we get 20 cfh so the boss won t replace them.

[Bob]

Great Question!
And thank you Dan for a good answer.

I have not been opening my valves all the way, nor bleeding everything down when shut off, and not backing off the regulator setting.

The regulator with my HH-135 (and probably the HH-175) has a screw and lock nut flow (pressure) adjustment. Might want to replace that with a knob with the same threads.

I did notice that with the tank off and the lines still under pressure the pressure does slowly bleed off. I think that means if you did not shut off the tank, you would slowly be loosing gas all the time.

Thanks again Dan
Bob

[Guest]

Originally posted by Bob
Great Question!
And thank you Dan for a good answer.

I have not been opening my valves all the way, nor bleeding everything down when shut off, and not backing off the regulator setting.

The regulator with my HH-135 (and probably the HH-175) has a screw and lock nut flow (pressure) adjustment. Might want to replace that with a knob with the same threads.

I did notice that with the tank off and the lines still under pressure the pressure does slowly bleed off. I think that means if you did not shut off the tank, you would slowly be loosing gas all the time.

Thanks again Dan
Bob

I hate to even jump in on this, but Dan is right, about the sticking guages, however, in the real world, most guys just turn the gas off at the tank, and it will bleed off by itself. There was quite a discussion on the news group about this in relation to Oxy/ Acetylene tanks, and about 20 or 30 guys chimed and nobody backed out the regulator when shutting down. I know they tell you to do it all the time, but the fact is, most nobody does it, and they have no problem not doing it, myself included. Like ROCK says, "Your call".

[Roger]

1. Turning off bottle stop valve then backing off regulators and bleeding down pressure is a welder's habit dirilled into them when learning gas welding as part of major safety procedure. Backing off regulator and and bleeding down isn't as valid with stable even inert shielding gas but I still do it. Life of regulator isn't affected much regardless.


2. Your regulator having screw with lock nut just shows the manufacture doesn't think backing off regulator is needed. If you often want to tweek flow adjustment then weld on a Tee handle. Or buy a ready made hand adjusting screw.

It is important to crack bottle valve slowly raising pressure to regulator and stand to side of gages and valve stems. Then open all the way. I have seen valve bonnet unscrew and top of valve with handle go flying. Only about 250psi in bottle.

Dan, I also have a very small shielding gas leak from begining with my MIG welder. I mixed up dish soap and water to bubble check all external fittings without finding leak. Think the solenoid valve is leaking through. Not enough to worry about.

With regulator was not attached to bottle. I would put a drop of halocarbon oil on threads of your seized regulator adjusting screw then wrench it. It would move or break. Either way it would be fixed.

Operating, maintaining and repairing gas systems was large part of my last job.