Where does the propane in my pipes go?

[jgerhard]

I'm so curious to see what everyone's take is on this.

Over the years, I've had travel trailers, fifth wheels, class A and class C motorhomes.

I use the same trick on all of them; after I turn the propane tank valve on, and before I turn on the fridge, I run the stove until I smell propane (if its been a couple months, it takes a while). The fridge starts much faster and all is good.

My question is, why aren't the lines still full of propane? Where does it go?

Is it:

a) Propane lines always leak a little in RVs?
b) Propane valves always leak a little?
c) The pressure is so low, the propane turns to crap?
d) Your solution here...

Thanks!

James

[SmokerBill]

It's reduced by hydrocarbon consuming microbes.

Microbes That 'Eat' Natural Gas : Oceanus Magazine

[jgerhard]

That's bizarre! I'm never smelling the pre-gas air again from my stove. Who knows what microbes I'm breathing in!

[us71na]

I've wondered the same thing. If valves are closed at both ends of the line, where does it go?

[TWP723]

Originally Posted by SmokerBill

It's reduced by hydrocarbon consuming microbes.

Microbes That 'Eat' Natural Gas : Oceanus Magazine

SmokerBill the science guy!

[Camper_bob]

Very interesting read!

I wonder though: The article says the microbes need a very specific environment to thrive and survive including the presence of sulfate for respiration (instead of the more common oxygen). I wonder if inside our propane lines and tanks would be that kind of environment? Most notably the absence of oxygen? Seems unlikely.

It also said that the process is very slow. From anecdotal experience, it seems like it doesn't take long for the need to purge the lines to develop.

Of course, it seems there is a lot of research to be done with those things. Would the microbes also eat the odor additive? But what is it they say about the simplest explanation often being the right one? I'm thinking there are micro-leaks in fittings that are allowing the propane to slowly bleed out of the system. But it could be microbes, or some combination of both?

[SmokerBill]

Actually, I was kind of joking about the microbes, LOL. I don't really have any idea of where the propane goes. Seems like the pigtails going into the tanks always seem to smell a little propaney. Maybe that's where it goes.

If not, it MUST be the microbes that have mutated into an RV-specific type.

[TWP723]

Originally Posted by SmokerBill

Actually, I was kind of joking about the microbes, LOL. I don't really have any idea of where the propane goes. Seems like the pigtails going into the tanks always seem to smell a little propaney. Maybe that's where it goes.

If not, it MUST be the microbes that have mutated into an RV-specific type.

[North of 49°]

I always just put it down to many microscopic leaks in the multitude of couplers and joints that make up the system, causing it to lose pressure over time. Individually, these tiny leaks don't amount to anything, but all together, it might be enough for the system to lose all its pressure. Our 24FBS, which has never had any work done on its propane system, loses pressure about as fast as our old hybrid, which has had every single propane appliance in it removed and reinstalled at least once over the years we've owned it.

[Rock]

Glad u brought this up since I forgot to do a leak check. Checking my systems out I fired off the Water heater and heater. After shut down I secured the propane tank valve and very soon after the guage turned From green to red. That to me seemed like a pretty quick lose of pressure in the lines.
Rock

[RoyBraddy]

Of coure my propane is feeding the stove top, water heater, and furnace. If I turn OFF the valves at the tanks I suspect these lines just slowly leak down until it is all gone...

When I turn ON a propane VALVE I always go to the stove top and fire it up hoping to see a BLUE FLAME eventuallly untill all of the air gets out of the line... In my case the stove top is the farthest away from the propane tanks... This helps the heater and furnace burners work better I guess...

When I have my tanks turned off and try to light the stove top I most often get one flash of fire so I guess some propane is still in the lines...

Roy Ken