Tank keeps shutting down.

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Heath Daily
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Tank keeps shutting down.

Post by Heath Daily » Thu Nov 23, 2006 5:55 am

I'm trying to get my engines to run and I keep losing the flow of propane from my 20lb tank. If the valve is opened slowly it will increase flow to a point, at which it will make a slight "click" noise and the flow is cut off until the valve is shut off and re-opened.

What gives?

Tanks is blue-rhino brand and has the new style OPD valve, but doesn't have the blue rhino only vavle.

I'm so close to running, but just can't keep the fuel flowing.

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re: Tank keeps shutting down.

Post by Johansson » Thu Nov 23, 2006 5:50 pm

I think that the valve has a safety feature that stops the gas flow in case of a hose coming loose or something similar, my bottle does the same thing on gasseous propane. Try to invert the tank and run it on liquid.

//Anders

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Re: Tank keeps shutting down.

Post by marksteamnz » Thu Nov 23, 2006 5:51 pm

Heath Daily wrote:I'm trying to get my engines to run and I keep losing the flow of propane from my 20lb tank. If the valve is opened slowly it will increase flow to a point, at which it will make a slight "click" noise and the flow is cut off until the valve is shut off and re-opened.

What gives?

Tanks is blue-rhino brand and has the new style OPD valve, but doesn't have the blue rhino only vavle.

I'm so close to running, but just can't keep the fuel flowing.
Tanks have flow restricters so if the hose is cut there is not a massive flow of gas. A small lightly spring loaded disk clicks shut untill flow is reduced. They have been fitted for many years. In a hot air balloon they are one of the scariest things that can happen.
You will have to remove the tank valve and pull it out which will probably cancel the warenty etc if you want a decent flow from the tank.
Cheers
Mark Stacey
www.cncprototyping.co.nz

Jim Berquist
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re: Tank keeps shutting down.

Post by Jim Berquist » Thu Nov 23, 2006 5:52 pm

Is it cold there, HA! Warm up your tank to room temp. If you have a regulator loose it....


Just some some thoughts.

Edited: They are right, it's the new valves have a safety devise preventing massive gas flow......I have a valve that does that if the coupling is not screwed in, just the right depth.....

Jim
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Heath Daily
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re: Tank keeps shutting down.

Post by Heath Daily » Fri Nov 24, 2006 4:50 pm

Damn. Ok, will tear a bottle down and see if I can work through the neutering technique. Of course then I gotta re-purge the air, etc, etc.

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re: Tank keeps shutting down.

Post by Eric » Sat Nov 25, 2006 1:18 am

I had the same problems with 40 pound tanks, since they have anti tip valves that also shut down with "high flow". I couldnt even run my propane torch at full blast without it shutting off. Eventually the mechanism wore out and got stuck in the closed position so I took it back and got a new tank.

The 20 pounders that I have dont have the shutoff built in, I will have to check what brand they are, I think they are still in production or at least still available.

Eric
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Heath Daily
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re: Tank keeps shutting down.

Post by Heath Daily » Sun Dec 03, 2006 4:41 am

Do either of these look familiar?
1st pic ignore the really old non-safety valve.

Image


Image

The first one with the white plastic peice is a brand-new unit from the local co-op.

The second one is from out of the blue-rhino tank and makes the CLICK when the float is lifted, just like when the tank shuts down. Both of them can be unthreaded and removed, but that removes everything including the OPD which I kinda would've like to have kept. I found no spring loaded disc either, unless it's this peice (in the center).

Image
[/img]

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re: Tank keeps shutting down.

Post by Eric » Sun Dec 03, 2006 5:22 am

I would try to find a 20 pound tank that doesnt have the stupid safety crap built in and just swap them. Maybe you have a friend that has a BBQ that does the "tank swaps" like you see at a lot of gas station's in those little storage lockers, that you could swap the valves from.

Make sure not to get anything in the tank while its open, store it with a plug to keep it from getting humid in there, and make sure to teflon the threads, and once they purge it and refil it, dont store it inside and only drive home with the windows down, and whatever you do, dont smoke! They say smoking can kill you and in this case it would be quite suddenly.

One of the retards at the local propane refil station filled 2 of my 20 pound tanks without even weighing them, just filled them right to the top. When I picked them up I was like HOLY CRAP THESE ARE HEAVY, well one blew off pressure in the car which filled it with propane!

When I got home I quick fired up some jets to burn off the excess.
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Heath Daily
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re: Tank keeps shutting down.

Post by Heath Daily » Sun Dec 03, 2006 3:11 pm

The local fillers won't touch an old style valve. But if you look the safety stuff just unscrews from the bottom of the valve. That top picture is an unused valve with fresh sealant / loctite on it. The other one is the one I pulled out of the tank.

Image

I'm just gonna have to watch them fill it to make double sure it's getting weighed right.

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re: Tank keeps shutting down.

Post by Dave » Mon Dec 04, 2006 12:32 pm

It is possible that the hose, not the valve, is the problem. First thing to check is for a flow limiter / excess flow device in the connector. These are typically visible just inside the POL (the connector that goes into the tank) and usually look something like a star washer backed up with a little plastic ball. Other times it is as simple as a very small hole in the POL to limit flow.
Dave

PS: See attached picutres. One with an excess flow device and one without. In this case I simply used a small screwdriver to pop out the star washer and the spring and ball just fell out...
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POL-with-Excess-Flow.JPG
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Heath Daily
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re: Tank keeps shutting down.

Post by Heath Daily » Tue Dec 05, 2006 3:56 am

My rig is definitely without that in the hose attachment. It's straight thru all the way. Thanks though, somebody is gonna save themselves days of aggravation if they read that at the right time.

I should get the bottle filled tommorrow and test again this weekend. I'll let you know how it goes.

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re: Tank keeps shutting down.

Post by larry cottrill » Tue Dec 05, 2006 2:06 pm

NOTE that the overfill protection valve was put there because less skilled people are now refilling these cylinders. People have been at least seriously injured from an overfilled cylinder:

The propane liquid goes in fairly cold, and gradually warms up as the cylinder is transported and/or stored. The liquid propane is imcompressible, but its volume expands slightly during warmup. IF the filling operator is convinced that the cylinder should be filled as full as possible, OR he's used to filling the cylinder until the overfill protection device blocks the flow, you will have a cylinder with insufficient expansion space. The steel shell is most definitely NOT strong enough to prevent bursting under liquid expansion.

Eric was lucky - there must have been a little expansion space left, so that the pressure rise was gradual, not catastrophic. The pressure rise from a liquid expanding thermally in a rigid cylinder with no "air space" is unbelievable.

If you don't leave that overfill gimmick in place, you'd better have these filled by someone with experience that you know and trust, who will fill them by measured weight alone.

L Cottrill

Heath Daily
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re: Tank keeps shutting down.

Post by Heath Daily » Sun Dec 10, 2006 2:52 pm

Dave, looks like I owe you an apology.

The freshly altered and filled tank STILL wouldn't run. I had to look way down inside the hose fitting to see it does in fact have a flow limiter. If you look at it without putting your face right up to it, you can't even see it. So, that's gone now.

Safety Note. Despite having watched and made sure that the tank was filled by weight, it vented a small amount once the day warmed up some. I don't know how much because it was strapped into the back of the truck and I only noticed it when I went to remove the tank. While not a huge amount it was clearly over-pressured. Having found the problem elsewhere I will probably reverse the valve modifications as they don't help and could cause serious harm.

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re: Tank keeps shutting down.

Post by Eric » Sun Dec 10, 2006 8:01 pm

I dont think there was any air space, it was just very cold out, even in the car it wasnt too warm. Apparantly a few other people who were there while they did it said they just let the pump run until liquid started to blow out of the overfil valve. I think the person who was doing that probably was fired.

When I get the tanks refilled I have been keeping my windows down after that incident.

Eric
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jerry marra
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re: Tank keeps shutting down.

Post by jerry marra » Wed Dec 13, 2006 8:14 pm

This is interesting and important:

Now to the new style excess flow check valve on the Acme nut that connects to the DOT cylinder's OPD valve. It is really a simple device. Inside the Acme nut, there is a ball bearing check valve that almost shuts off momentarily when full pressure is released by opening the cylinder valve. You should hear a click at that point. It doesn't shut down completely, as that would negate its ability to detect leaks and excess flow from a leak or major line break, and no gas could flow. It closes just enough to allow a bypass of gas that is very slight, about 10 cubic feet or less per hour (cf/hour) flow, as opposed to the max flow of 200 cf/hour. The bypass gas goes into the propane system, and if there are no leaks or broken pipes, it backs up and builds pressure in the gas lines in the RV. When it equalizes on both sides of the valve, the valve opens to allow full pressure up to about a max of 200 cf/hour at 100 psi. Then if you were standing there, you would hear a second click. Using all of your propane appliances should not exceed 100cf/hour. If there is a leak or a broken pipe, the pressure can't build up and the excess flow valve doesn't open up all the way thus limiting the gas output to about 10 cf/hour, or less. It is important to note that propane, like gasoline vapor, has narrow ignition requirements as far as air fuel mixture is concerned. So if you lit the leak (Don't try this at home!) it would show a flame at the leak in the air, but the concentration is too high in the line for it to ignite. In other words the fire can't run up the line to the cylinder or tank to ignite it. Want to see it in action? Watch your gas range work. Why doesn't the flame travel up the tube it comes out of to the burner? Same thing.

Sorry for the long post

thanks

pulso57 :shock:

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