Propane leaks during storage.

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.

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

^ 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? :)

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.

Normal to have to 'bleed' propane system after non-usage

BUT you are NOT bleeding AIR out of the system.
When all propane appliances are tuned off the LP Reg goes into 'lock-up' mode to prevent HIGH System pressure (static)

Then when placing system back in service the REG needs to come out of 'lock-up' status and establish flow----need a demand to do so.
At 11"WC (0.4psi) establishing that FLOW thru out the system can take several minutes and lines to each appliance will need to have flow fully established by those individual appliance gas valves opening.
Some will require several attempts due to appliance gas control/flame sensing.

Stove top is easy due to NO flame sensing ----turn knob, spark/match and light the flame.
That first demand palces REG in service and starts establishing flow

Propane has a narrow ignition window and until proper flow is established the air/fuel mixture will be unbalanced so it may seem like 'air' is coming out but it really is propane at low pressure which needs to come to full sstem pressure so that the correct air can be pulled in thru appliance burner 'air' inlets to mix with the propane at full pressure for correct combustion ratio

NO AIR.....just low propane flow/pressure

Absolutley NORMAL

BFL13 wrote:
How long a time is "extended"? All winter or between trips because there is no parking at home?

Maybe not the same as with bottles, but if the big tank in our Class C is turned off for a few days, and then opened, it takes a couple of tries to get the furnace to light, but the stove lights up ok.

That's a good question about the length of time in storage. I don't think I've noticed an issue with a week between uses. But the majority of my storage is a month or more between trips.

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

I need to bleed most of the time...twenty seconds or less at the stove and then the fridge lights very quickly.

How long a time is "extended"? All winter or between trips because there is no parking at home?

Maybe not the same as with bottles, but if the big tank in our Class C is turned off for a few days, and then opened, it takes a couple of tries to get the furnace to light, but the stove lights up ok.

Yes, absolutely normal.