I have a newer Marshall Brass Extend-A-Flow tee on my coach. It's been perfect for two years, using portable 20-lb bottles to keep me warm. I routinely swap out bottles without trouble.
Lately, I thought I had a bad regulator or clogged supply line, but that seems not to be the problem. It turns out, when I notice the water heater running a flame more like a Bic lighter, or the catalytic heater giving off very little heat, that the "excess flow" protection has triggered. (And, of course, the big furnace won't even light with such low gas pressure.)
Once I shut everything off and allow it to reset, we're back to normal. At least for a while. So my question is: in the absence of any "excessive flow," why is the excess flow protection protecting me? Is this a known failure mode? Is this the beginning of the end for my Extend-A-Flow?
I don't have a leak, I don't have excessive flow, and I'm not doing anything different. Is a new tee in my immediate future?
I THINK the excess flow protection is contained in the POL at the regulator side of the tee -- I guess I could just replace that? The benefit of your experience will be appreciated.
Actually it is in the valve on the bottle. If you open it too quickly, you can activate it. If your demand is too great, it can trip it. The water heater and the furnace are the greatest demands on you propane. If it is close to the valve rating, anything else on may trip it while the furnace and water heater are running.
2010 Ram 3500, Crew Cab, Long bed, 4 x 4,Dually, Lights & Siren!
I had the same problem a couple of years ago. Replacement of the hose between the automatic change over and the tank fixed the problem. I believe the excess flow valve would be designed to fail in a safe mode.
eHoefler wrote: Actually it is in the valve on the bottle. If you open it too quickly, you can activate it. If your demand is too great, it can trip it. The water heater and the furnace are the greatest demands on you propane. If it is close to the valve rating, anything else on may trip it while the furnace and water heater are running.
Actually, it is not in the valve at all. The Overflow Protection Device is contained within the POL/Acme fitting on the end of the rubber propane hose that screws into the valve.
The only safety devices contained in a portable tank valve is the Overfill Protection Device float valve and the high-pressure safety release valve.
(This is why the poster above (shooter) fixed his problem by replacing the propane hose).
This also why, when a tech needs to empty a propane tank, he can screw a blank POL fitting into the tank to activate the check-valve and then open the valve and purge the tank releasing full, non-regulated pressure. Done this a few times myself.
BTW, the POL/Acme fitting and hose assembly also usually contains a temperature activated device that shuts down flow in the event of a fire.
* This post was
edited 03/27/12 05:36pm by Ex-Tech *
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