Propane leaks during storage.

[opnspaces]

Is it normal to have to bleed air from the system when you get your rig out of storage? I do shut the propane off when I drop the trailer off for storage. And I always considered it normal to have to bleed the air out to get ready for a trip. But lately I've been wondering if this is normal, or if I have a leak. So I figured I would see what your experiences are.

Do you (you personally not you hypothetically) have to bleed air out of your system if you shut the propane off for an extended period of time?

Oh as far as normal. I realize that by design there should be no leaks during storage unless you open the system somehow. But with how cheaply these components are made I would consider it normal if the majority of you also have to bleed the air out every time.

[opnspaces]

^ Thanks for the heads up. I already did smell propane one day and had to replace the regulator on the Jayco. That was quite a few years ago now that I think about it.

[time2roll]

Keep your nose tuned to the possibility of a leak near the regulator.
If the regulator is original in the two RVs in your signature it would be OK to just replace them.

[deltabravo]

ford truck guy wrote:
Normal.... been doing that for MANY years.... I used to start with the high output burner first, when I had 1. .

Ditto. All 6 RVs I've owned since 2003 have been like this. (or has it been 7 - I lost count)

[dougrainer]

RJsfishin wrote:
I never have the problem, I just leave the propane on all the time.
When there is no leak, there is no reason to turn it off.

Not a good idea if you are not using the RV. Doug

[red31]

dougrainer wrote:

red31 wrote:
Time + thermal cycling w/leaks causes vacuum to suck in air.
the longer closed and not used yields more air.

Yes, but HOW MUCH VACUUM needs to be generated to PULL the outside air IN thru Rubber gaskets/seals? I doubt atmospheric Vacuum can pull air in thru a tight almost completely sealed system. Doug

VERY LITTLE, I have no doubt (goes both ways). Open and close over short periods and there is little issue, close for weeks/months and the issue is there.

If 15.5 psia can leak to 15 psia then cooling and the pressure drops to ?? 14.5 psia or less?

The stick lighter flicker is my clue (long periods of closed) that it ain't propane causing the flicker.

[RJsfishin]

I never have the problem, I just leave the propane on all the time.
When there is no leak, there is no reason to turn it off.

[C_Schomer]

Micro leaks and thermo cycling makes the most sense to me but I have another explanation... sp!t happens! Craig

[dougrainer]

red31 wrote:
Time + thermal cycling w/leaks causes vacuum to suck in air.
the longer closed and not used yields more air.

Yes, but HOW MUCH VACUUM needs to be generated to PULL the outside air IN thru Rubber gaskets/seals? I doubt atmospheric Vacuum can pull air in thru a tight almost completely sealed system. Doug

[red31]

Time + thermal cycling w/leaks causes vacuum to suck in air.
the longer closed and not used yields more air.

[dougrainer]

Chris Bryant wrote:
I’ll give yet another explanation. Electronic valves do not seal 100%, and they are all basically one way valves, offering no resistance backwards. LP gas is very temperature sensitive- the lp that remains in the lines at atmospheric pressure after they have leaked down will expand and contract with ambient temperature, it gets cold, and the pressure in the line is below atmospheric,,drawing in air to the system.

Let me ask you this. The LP in the line is at pressure. It slowly leaks OUT due to pressure pushing it out. Does it not seem logical, that at some point after leaking down the in line pressure and the atmospheric pressure will be equal? The existing LP vapor left cannot exit OUT because there is no excess pressure to overcome the outside air. So, you reach a stand off. This is how I look at it. Doug

[Chris_Bryant]

I’ll give yet another explanation. Electronic valves do not seal 100%, and they are all basically one way valves, offering no resistance backwards. LP gas is very temperature sensitive- the lp that remains in the lines at atmospheric pressure after they have leaked down will expand and contract with ambient temperature, it gets cold, and the pressure in the line is below atmospheric,,drawing in air to the system.

[dougrainer]

The VERY SMALL (microscopic) possible leak in the rubber parts of the closed LP system WILL leak out over time. BUT, while the LP has leaked out, there is no way for AIR to then migrate IN. It took pressure to force the LP thru the microscopic voids in the seals. So, when you find the LP has dissipated from storage, when you open the tank valve, all you are doing is filling the lines with LP vapor and basically going down an empty pipe. Doug

[opnspaces]

^ Old-Biscuit: This is purely an academic question as the real question was is it normal. But I am interested in this aspect as well so thanks for bringing it up.

I mostly follow, but does the odorant dissipate or maybe settle over time? I ask because out of curiosity I have more than once stuck my nose down by the stove burner and taken a big whiff when I first turn the system on. I usually get a faint propane smell which is why I figured it was air.

Has anybody else taken a whiff or am I just kind of "different" in that aspect? 🙂

[exit_295]

Thank you Old Biscuit. Finally an explaination that is difinitive and actually makes sense. I have questioned the "bleeding the air out of the lines" reply for years but did not know about the regulator having to adjust itself after coming out of closure.