Recent screw-up

awellis3 · 05-01-2012, 12:10 PM

Thought I'd give y'all a heads up in case someone doesn't know this.
On a recent boondocking trip in the pop up, Penny said that the stove just went out. We have auto changeover and the second bottle was full, yet the gage showed red. Aha! I had neglected to turn the valve on the tank to "on," so I did. Nothing. No gas. Indicator still red. Moved the service lever to the full tank. Zilch - still red.
Took empty bottle off and borrowed neighbor's full tank, hooked it up and Walla! With two full tanks, gas flowed and all was well. Removed neighbor's loaner, put empty tank back on, hooked it up (leaving the service lever pointing at the full tank) and all was well.
Conclusion: When the auto valve switched from the now empty tank to the tank with the closed valve, it thought it was empty, too, and just shut down and refused to budge. Moving the lever had no effect. I blew its little mechanical mind I guess, and it was stuck in "no man's land."
Putting another full tank on must have recentered the mechanism.

Live and learn,
Teach
p.s. - At least this all happened at lunch time, not bed time - whew!

Gene · 05-01-2012, 06:37 PM

Think of it as a new learning opportunity.

I know I just learned something new to file in the mental archives .... just in case.

**JohnB** · 05-01-2012, 06:55 PM

Hi Teach,

While we are on this, there is another factor, actually a saftey factor.

When they went to the new style tank fittings, looks like this (Acme thread nut)

They included an anti slug saftey valve in side. It will only allow so much gas to flow and if it is exceeded it shuts down and will stay that way until the pressure equalizes upstream and downstream of the fitting.

And there are also different color nuts. The black nut is the smallest flow size , then green, and then a Blue. Each one goes up in the orifice size inside to only deliver a certain amount of BTU's of energy. This is why your BBQ has a black nut and the camper with a furnace and HW heater has the green 75,000 BTU nut. They created the orifice and a slug feed valve based on the max need verses the old large hole in the older left hand thread stye fittings where it gave you more gas then you ever needed. Not good in a saftey situation.

It is very common if you turn on a LP tank valve real fast, you over feed the slug valve and it will go into saftey and only pass a very small amount of gas. The stove may not even light in this condition. It thinks there may be a wide open hose of fitting down stream.

Once the pressure down stream builds to equal the pressure upstream of the fitting, it resets the slug valve and then gas will flow. This equalizing process can take a few minutes when the down stream opening is sealed up. So just turn on the gas valve real slow and this will not happen. If it does, close the tank, close all down stream devices and well just wait until the pressure equalizes it self. Then turn on the tank slowly.

Now add the auto switch over regulator. It too has internal pressure checks. In your existing case the slug valve in the ACME nut may have shut you down Or the switch over regulator or both.

If you may have waited long enough it might have reset. Or worst case, unscrew both tanks let the ends of the hoses bleed out and then flip the change over regulator to the good tank, screw all hoses back on and slowly open the full tank. OR shut the tank off, bleed out the pressure from the stove and once bled, turn stove off and slowly turn on the tank and start over.

I think by you moving the tanks around you reset the safety.

I had a buddy who had a 2 burner Camp Chef stove that has the monster 35,000 BTU cast iron burners. He slugged the system when he turned it on and lit the stove. The burner lit but only on super low. It would barely stay lit. And it stayed burning this way for 5 to 10 minutes as he tried to figure out the problem. Since the slug valve went into saftey and the down stream flow never had a pressure build up as the stove burner was using all the pressure available, the saftey would not reset. When I saw this we talked and I said, I bet your slug valve is stuck on. Closing the tank, letting it bleed out the stove to zero, then turning the tank back on slow reset the valve from safety.

Hope this helps

John

awellis3 · 05-02-2012, 05:04 AM

Quote:

Originally Posted by JohnB

In your existing case the slug valve in the ACME nut may have shut you down Or the switch over regulator or both.

Since I always open valves slowly, I think it was the switchover.

Quote:

I think by you moving the tanks around you reset the safety
John

I think it was getting the pressure equalized. I did a variation of your suggestion. Instead of bleeding all gas out, I filled the lines with equal pressure.
So, if I put a black Acme nut on my trailer, I can turn my stove into a foundry?

Teach

**JohnB** · 05-02-2012, 08:11 PM

Quote:

Originally Posted by awellis3

So, if I put a black Acme nut on my trailer, I can turn my stove into a foundry?

Teach

Well, no. Right now with the Green nut you have 1/2 a foundry. The Black nut is a 1/4 of a foundary. And a Blue nut is a full foundry...

And by now I think we may both be a little nutty...