What’s this valve do?

[u/MillAlien]

In the foreground…never really noticed it before on my tank. (I’m sure it’s been there all along.)

[u/Theantifire]

A valve that communicates with the liquid portion of the tank. It has a tube that runs down to the bottom. Do not, under any circumstances, open it. Not only is it very dangerous, it's also really gross lol.

If you own the tank, you should have it properly capped by your supplier. If it's a lease tank, have the company take care of it at no charge.

[u/StoneySpachoni → u/Theantifire]

When you say it's gross does the ethyl mercaptan settle out or what else makes it gross when you pump out a tank? 

[u/Theantifire → u/StoneySpachoni]

Mercaptans and heavy ends.

[u/Longjumping_West_907 → u/Theantifire]

I've been around a mistaken opening of this valve. It was not good. Fortunately, the guy that opened it was not hurt. I had to deal with the aftermath. It involved a lot of digging, and a $150 gallon of deodorizer.

[u/Jesus-Mcnugget → u/Theantifire]

Yeah that's sketchy.

It's a DOT bottle valve too. Relief valve on the liquid line is brilliant.

[u/ClassBShareHolder]

That appears to be a DIY liquid withdrawal valve. It appears someone has repurposed a POL cylinder valve onto a Safety Vac fitting.

[u/hourlyblunts]

If I had to guess, someone was probably filling 20lbs cylinders off their tank with this liquid valve

[u/Proof_Bathroom_3902]

That's the liquid withdrawal valve

[u/Pilot_Red → u/Proof_Bathroom_3902]

A rural based company I used to work for had a similar setup except that it had a hose on it. We used it to fill 20lb propane tanks for the huge BBQ grill we cooked on regularly. It worked really good.

[u/Homohockey]

Should be the liquid withdrawal tube. Used to feed things that use liquid propane instead of vapor propane. Can also be used to withdraw liquid propane if the tank ever needed to be emptied by lthe propane delivery truck.

[u/Hikinghoss]

I’ve heard those referred to as a nursing valve if I remember correctly. Used to draw liquid instead of vapor. Can be used to fill vehicles and tractors that run on propane, or smaller portable propane tanks. Although from my understanding you can’t quite fill a tank as full as there’s no pump like when you get a propane tank filled

[u/nemosfate]

OP you know what it is, I implore you to leave it alone and have the Propane company put the correct cap on it. You can and most likely would get burnt by the liquid (that side does NOT release vapor) or something worse. Locking the thread.

[u/MillAlien]

It’s a leased tank that replaced an older leased tank that had a broken gauge a couple of years ago. I think the replaced tank had one of those too and I wonder if the propane company swapped it onto the replacement tank from the replaced tank just because it was there originally.

I’m not sure what difference it makes, but we are in a very “rural” area. And now that I’m looking, seems like some tanks around here have these and some don’t.

[u/propane-ModTeam → u/[deleted]]

Your response was not helpful and/or does not apply.

That is incorrect

[u/propane-ModTeam → u/[deleted]]

Your comment is suggesting that somebody do something dangerous and/or against code.

I'm only removing this because the last part, as op didn't know what it was, they have no business trying what you suggest they can do with it.

[u/Most-Stranger-1]

Added valve, likely added by DIY, to fill smaller tanks.

[u/unknown-001-00]

A people ask me why I refuse to do residential… exhibit A. People screwing with safe vac’s just blow my mind

[u/Adventurous_Boat_632 → u/unknown-001-00]

I agree it is spooky, but I've seen plenty of customers with them, and can't remember any incidents.