Leaking propane tank.

[swimmer_spe]

I had a full 20lb propane tank sitting in my garage. I noticed a smell of propane and there was an odd noise coming from it. Turns out, the relief valve was letting propane out.

I am wondering if due to the heat we now have if it wasn't overfilled.

Do those relief valves reseat, or do they keep relieving till empty?

It is sitting outside, far from any source of flame or ignition.

[drsteve]

mbopp wrote:
Which bodes the question - why do RV manufacturers use black propane tank covers?

Because the white ones get nasty looking after a few seasons. At least that's the only reason I can think of. Unless black plastic is cheaper...

[dougrainer]

JimK-NY wrote:
I have had tanks filled and then gone out into 90 degree temps. Never had an issue or venting. Recently I got a new tank, used it for a while and then disconnected the hose. It made a lot of noise and leaked propane. It soon stopped but I am going to exchange the tank anyway.

I have asked. No one seems to care about exchanging an old or defective tank that should be discarded. You also need to be careful about the tanks you get from the exchange facilities. I have had issues with tanks from Home Depot and Lowes. Tanks are often grossly out of date with no stamp indicating recertification. Dealers are not allowed to refill them. Another issue is the amount of propane in the tanks. Exchange tanks are filled to 15 pounds instead of 20 pounds. So you are paying for a tank that is only filled to 75 percent of capacity.

You have never had a problem because your tanks were filled CORRECTLY. Also, I did NOT state it always happens. I stated what "May" cause this to happen. Doug

[swimmer_spe]

Yeti plus wrote:
Swimmer, since you are in Ontario, it is my understanding that your house insurance doesn't like propane tanks stored in a garage or dwelling unit. Mine are on the trailer or in the camper or outside.
If the tank released enough propane, just a small spark could ignite and burn the garage down.
Brian

I will need to look into that. Mind you, after this, I will leave it outside.

[Yeti_plus]

Swimmer, since you are in Ontario, it is my understanding that your house insurance doesn't like propane tanks stored in a garage or dwelling unit. Mine are on the trailer or in the camper or outside.
If the tank released enough propane, just a small spark could ignite and burn the garage down.
Brian

[RJsfishin]

If you had a relief valve suddenly pop off releasing a large amount,....even for a second or 2, I dare say the valve was defective, or sticking. They are designed to release excess propane slowly as is needed to keep from over pressuring, and so that the propane will dissipate for safety reasons.
Even the little 1 lb bottles will bleed off slowly when refilled/overfilled.

[ScottG]

Joe417 wrote:
I've experienced the relief valve venting on 3 occasions over the years and they didn't leak a little. They popped wide open, putting out a cloud of gas, vented for a few seconds and then closed back.

Scared the heck out of me for just a second. Never had one that leaked a little.

It may be a different method of venting I haven't seen.

This is what I witnessed too. It was a massive burst of vapor 10~12 out from the tank but only last a second.
There was nothing small about it.

[wgriswold]

dougrainer wrote:
In my LP education class, they gave an example. You fill your DOT tank at 50 degrees and full. You then go to an area that has 100 degree temps with the never used tank. Odds are the tank relief will vent. MORE so, if they did NOT fill by weight and waited for the 80% to spew. The Auto shut offs are not that reliable to prevent overfilling. Doug

PS, this is why you NEVER leave a DOT tank in your vehicle or storage of your RV. That temp rise is dramatic.

Or any enclosed space.

[swimmer_spe]

mbopp wrote:
Which bodes the question - why do RV manufacturers use black propane tank covers?

Mine are white.

[SaltiDawg]

agesilaus wrote:
Probably the best thing to do is let it vent completely and then take it to one of those local places that exchanges tanks. Exchange it for a different tank and, if they will let you, pick one with a recent inspection date. ...

Or just steal one from a neighbor or Church.

[JimK-NY]

I have had tanks filled and then gone out into 90 degree temps. Never had an issue or venting. Recently I got a new tank, used it for a while and then disconnected the hose. It made a lot of noise and leaked propane. It soon stopped but I am going to exchange the tank anyway.

I have asked. No one seems to care about exchanging an old or defective tank that should be discarded. You also need to be careful about the tanks you get from the exchange facilities. I have had issues with tanks from Home Depot and Lowes. Tanks are often grossly out of date with no stamp indicating recertification. Dealers are not allowed to refill them. Another issue is the amount of propane in the tanks. Exchange tanks are filled to 15 pounds instead of 20 pounds. So you are paying for a tank that is only filled to 75 percent of capacity.

[mbopp]

Which bodes the question - why do RV manufacturers use black propane tank covers?

[red31]

nfpa 58 Table 4-4.2.2(a) Maximum Permitted Liquid Volume (percent of total water capacity): Aboveground Containers 0 to 1200 Gal (0 to 4.5 m3)

shows 80% @ 40F is the equivalent of 95% @ 130F

larger above ground containers have a different table as does below ground which allows for higher % fill using variable liquid level gauge and thermometer.

[dougrainer]

In my LP education class, they gave an example. You fill your DOT tank at 50 degrees and full. You then go to an area that has 100 degree temps with the never used tank. Odds are the tank relief will vent. MORE so, if they did NOT fill by weight and waited for the 80% to spew. The Auto shut offs are not that reliable to prevent overfilling. Doug

PS, this is why you NEVER leave a DOT tank in your vehicle or storage of your RV. That temp rise is dramatic.

[red31]

should reseat https://www.propanecouncil.org/uploadedFiles/Council/Research_and_Development/FS_10202%20Pressure%20...

weigh it! this should confirm if it is overfilled.

On a cool morning, connect an appliance to it and vent more.