LP gas leak down

[pawpaw]

Update:

My Jayco dealer could find NO LEAKS in the LP system. They checked the entire system with a sniffer and did a water column test. It held 11.5 wci for three days. I'm satisfied that problem is simply the gas/liquid situation that was mentioned above.

Thanks again guys for all your input!

[mcfarmall]

Still trying to wrap my head around how LP in a gaseous state can magically "change" back to liquid in the lines. Vapors from a liquid that boils at -44 F would have to be compressed in order to change back into a liquid.

[wwsmith111]

I think the problem (which I have to) and many others is that the propane is not leaking out as our propane tanks would go flat, but that the check valves in the system are closing when not being utilized. It may take more flow for them to open back up than just the fridge trying to light. For example, every time I open a stove top burner the fridge will light afterwards without fail. Although this purges the system it also opens the check valves back open. I am just guessing, but this makes sense if in fact this is what is happening. I think the fridge probably lit then went back out quickly once the propane ran out since the check valve was still closed shutting off the gas. Not sure if there is a solution to this other than cracking the stove top for a second or so every time one is going to switch to propane. Again, not specifically to purge the system, but to open the check valves so additional propane can flow.

[qwed94]

wwwsmith, you are on the right track. The problem though is likely when we open our valves. I know when I dispense propane at work. I have to open all the valves real slow. If you open a valve too fast, it "vapor locks" - sort of - then it wont dispense anything until the "lock" flows thru and opens the lines. That "I THINK" is why we have to light the stove top first and clear the lines, before any other appliance works.

[wwsmith111]

I leave one propane tank on all the time. We keep our TT behind where my wife works and also keep it plugged into shorepower. Everything works on gas with no problems whenever we use it except switching the fridge to gas if we haven't done it in a while or even the next day. If I don't crack a stove top burner first it will have a blinking warning gas light in a minute or two. If I then crack a stove top burner and reset it it will lite every time. If I leave it on gas after that I never have a problem. That is why I think the check valve closes for safety reasons and the fridge just doesn't draw enough to open it. But once it's open it keeps working until you shut it off again for some time then the check valve closes and the problem starts all over again. Of course I don't know this for sure, but I think it makes sense.

[RedHorse1]

WW, you may be on to something. Both our TT's have done this. I found that after cycling the fridge about 3 times it would eventually light (meaning let it time out trying to light 3 times). I've given up worrying about it and automatically light the stove first. There's so many folks checking in with the same issue I'm telling myself it's just the way things are.

[wwsmith111]

I read several other threads on other forums concerning this problem. It seems that one common problem has to do with newer style fridge control boards having overly sensitive thermocouple circuits causing them to have a recurring check light problem when one switches to gas. If the unit lights after two to three tries then an overly sensitive control board may be the reason. Here is an apparent solution: http://www.pplmotorhomes.com/parts/r...r-dinosaur.htm The replacement control boards made my Dinosaur," An improved thermocouple circuit eliminates the recurring check light problem." They also have control boards for other brands such as the Norcold but they are pricey. The link is for the Dometic brand.