Coleman Propane Stove , 20# tank problem

[atahoekid]

I rigged up what i thought was a smart way to run both my coleman stove and cabin heater from a 20# propane tank. Apparently, I was wrong. The heater works great but the stove runs for a while then quits.

Here's the set up. I don't think there's a flaw in there but maybe I missed something or am unaware of something.
The 20# bottle sits on the tongue. A tee right at the the bottle splits the flow to the stove and heater. The stove side goes from the tee via a hose to a 3/4" black iron pipe that runs the length of the trailer. At the far end of the pipe is a reducer into which is a fitting. The fitting is capped with a plastic cap during driving so no debris gets in the fitting. At camp, I will attach a hose to this fitting and the other end of the hose is attached to the standard "regulator" that comes with the stove and into which normally goes the 1# bottle. I'm using propane fittings and hoses, I'm not trying to short cut or gimmick the setup, I'm just not sure what's happening.+

Since it runs and then quits, I'm thinking maybe the regulator is shutting off. The stove runs great on 1# bottles, but I hate the waste and the expense. Anybody have an idea of what is happening?, why?. What's the fix?

[Dale M.]

Could be something "marginal" with connection where stove hose connects to black iron pipe.... Need a bit more details on what you are doing... IS the 3/4 in black iron pipe (which is way to big) at "tank pressure" or is regulated down at tank... If its regulated down, it may be pressure is to little to keep stove regulator operating and it is just shutting down...

Most of these stove regulators want to see "tank pressure" (about 125 psi) at inlet (disposable canister fitting)....

IF you are running tank pressures full length of plumbing under trailer, its not really a good idea.... Might want to consider a different stove that operates at typical regulated pressures (generally about 1/3 psi), regulated at tank...

Dale

[atahoekid]

The pipe is at tank pressure. Looked for 1/2" pipe when I installed the pipe but couldn't find any locally. I do drain it and disconnect all the fittings while traveling, so I think it's pretty safe. There is plenty of pressure built up in the pipe (which I discovered when I tried to disconnect prior to bleeding everything down). I'm stumped. I was thinking it might be too much pressure.

[High Desert]

Mel, have you tried the stove on a 1# bottle since it started acting up? Also, when it shuts down can you here propane coming through the burners, or is the flow cut off?

If it turns out to be the stove, I have a good Coleman propane one you can have.

[desertmoose]

Mel:
I wonder if the excess flow valve is giving you fits. With a 10 foot? long 3/4" pipe, that's a lot of volume to pressurize when you open the tank valve. It might be enough the excess flow valve in the tank shuts down and you get a greatly reduced flow out of the tank,

Having pressure in the line doesn't mean anything, any flow will pressurize the pipe over time.

Try disconnecting the tank, then reconnect the tank and open the tank valve just a crack. As low as you can turn the valve.
Walk away for an half hour and let the pressure in the pipe stabilize.
Then go ahead and open the valve all the way and try it out.
I'd bet that it will work just fine then.

Sam

[atahoekid]

Hey guys. I have tried the 1# bottle since the start of this mystery and the stove works fine.. I'll give the method a try and see if it fixes the issue. Interesting!!!

[warnmar10]

Mel:
I wonder if the excess flow valve is giving you fits. With a 10 foot? long 3/4" pipe, that's a lot of volume to pressurize when you open the tank valve. It might be enough the excess flow valve in the tank shuts down and you get a greatly reduced flow out of the tank,

Having pressure in the line doesn't mean anything, any flow will pressurize the pipe over time.

Try disconnecting the tank, then reconnect the tank and open the tank valve just a crack. As low as you can turn the valve.
Walk away for an half hour and let the pressure in the pipe stabilize.
Then go ahead and open the valve all the way and try it out.
I'd bet that it will work just fine then.

Sam

Dew whut?

Not arguing but not understanding either. Some sort of safety mechanism in the tank valve not allowing flow when it encounters a pressurized line?

[desertmoose]

Mel:
I wonder if the excess flow valve is giving you fits. With a 10 foot? long 3/4" pipe, that's a lot of volume to pressurize when you open the tank valve. It might be enough the excess flow valve in the tank shuts down and you get a greatly reduced flow out of the tank,

Having pressure in the line doesn't mean anything, any flow will pressurize the pipe over time.

Try disconnecting the tank, then reconnect the tank and open the tank valve just a crack. As low as you can turn the valve.
Walk away for an half hour and let the pressure in the pipe stabilize.
Then go ahead and open the valve all the way and try it out.
I'd bet that it will work just fine then.

Sam

Dew whut?

Not arguing but not understanding either. Some sort of safety mechanism in the tank valve not allowing flow when it encounters a pressurized line?

The new valves on propane tanks have a "Excess flow cutoff valve" built in to them. The purpose is to cut down on the flow of gas if there should be a broken line or something.
Great idea, except they are (IMO) too sensitive.
When you open the valve that's connected to a long, unpressurized hose or pipe in this case, there is a rush of gas thru the valve.
The excess flow cutoff valve then triggers and cuts the flow down to a trickle.
To reset the valve, you need to shut off the tank, unhook the hose on it, and then reconnect the hose.

In Mel's case, I think the valve gets triggered when he first opens the tank. The minimal flow coming from the tank will pressurize the pipe to full pressure. (after a while) Then when he lights the stove, the gas under pressure in the pipe flows until the pipe is "empty" then the minimal flow coming through the tank valve can't keep up, and the stove goes out.
Apparently the heater uses a small enough amount of gas that the flow from the triggered valve can keep up with it.

The only way I have found to get around this is to barely crack the valve when first opening it. Then the flow is small enough it won't trigger the excess flow valve. Once the pipe/ hose is up to full pressure, you can open the valve all the way and go ahead and use it normally.

Sam

[atahoekid]

That's sound like a reasonable explanation. I should be able to try it tomorrow. Thanks

[germanteardropper]

heye all,

I was reading this thread and thought to put my 5cents to it.

First i need to agree with Sam(dessertmoose), the 'problem' with the new valves is that the tend to 'close' and then let a litle of gas through.

being a plumber i do my share of gasfitting (did also gassfitting on traveltrailers) and i think u need to reduce the diameter of the gasline to 1/4" or 3/8" copper.

U can protect it with a regular gardenhose agianst roaddebrie(worked for my traveltrailer for 5 years with 5000miles a year on the dutch/german roads)

greetz from germany and happy camping

Richard

[mary and bob]

I think Sam has the right idea on the problem here. And Mel is correct in using the iron pipe for his line, but maybe oversized. There was a recent discussion on another trailer forum about some RV code for running propane lines, but I can't find it again. Basically it read that exposed outside lines must be iron pipe, and any connections must be accessible in order to check for leaks. But I believe that most camper manufacturers just used 3/8" soft copper line as it was much easier. One of our campers is a first year of production fiberglass Uhaul camper. All the propane lines are copper except for the hose from the tank to the regulator. Uhauls' repair manual has instructions to their service centers to replace the copper line with black iron pipe, so they either had problems with the copper line, or decided that they would have less liability issues by following code.

[warnmar10]

... so they either had problems with the copper line, or decided that they would have less liability issues by following code.

FWIW - I just watched a 2012 episode of How It's Made in which the manufacture of a Safari Condo Alto was featured. One of the first steps documented was the installation of a soft copper propane line that ran from the tongue mounted tank to the interior mounted stove. The copper line ran inside an aluminum C channel frame rail and was supported at several points by molded polystyrene blocks to prevent it contacting the aluminum frame rail.