Do you obey this sticker?

[redcedar]

Above the 7gal propane tank on my Baja there is a sticker that says you should not fill your tank above 80% capacity for risk of fire ect. Is this just lawyer speak or is there something to this?

[Jmooney]

Most fill stations won't fill them past that level (weight) anyway. Because it's a liquid that sits in the bottom of the tank, with a layer of gas above it, the tank needs space for that gas layer, or the pressure in the tank will get too high

[Higgy]

Maybe because you could end up getting liquid propane running through the hose instead of the gas you normally get. If that happens you will lose your eyebrows and maybe a lot more.

[VicS1950]

Originally Posted by redcedar

Above the 7gal propane tank on my Baja there is a sticker that says you should not fill your tank above 80% capacity for risk of fire ect. Is this just lawyer speak or is there something to this?

I am not familiar with that particular sticker, but I will say this.

As it is a larger sized tank I presume that you will pay to get your propane refilled as opposed to some DIY aftermarket refill adapter. The professionals that refill the tank should have some training and experience. Adding to that, later model and even older propane tanks are required to have safety systems included in the valve assemblies to prevent overfill. Professionals are trained to recognize the latest design valves and are forbidden to refill tanks that still have the old style units.

To top it off, even the tanks with older style valves include a safety pressure relief valve to address over-pressurization due to heat expansion. Not an ideal solution, but it works.

To summarize. You are correct to blame "lawyer speak".

Just my opinion. vic

[Grumpy]

Even MH tanks have 80% valve built in so they can't be filled beyond that.

[wags999]

Propane filling pumps will only fill to the proper level.

[Wrascal]

Same-same with my home tank. While rated at 250 gal my Propane company won't fill beyond 200 gal (80%). This is a federal safety rule on refilling propane tanks.

[PhyerPhyter]

The 80% fill rule is a preventative safety measure against the fluctuations that happen inside a tank. Propane, like water, will expand when heat is added to it. Propane, however, will increase in volume nearly 17 times greater than water over the same temperature increase. To allow for this expansion, propane containers are filled to only 80% of their capacity.

[redcedar]

Good to know. Is it true you can determine the propane level by tapping a coin on the side of tank from the top down and listening to the sound (pitch) change?

[Trippers]

I had my tank refilled by a local 'professional' and after being on the road, in 115 degree heat, stopped at a rest area. Heard a hissing and smelled propane. Decided to get moving quickly back on the road before the propane accumulated under the RV, believing that the excess would vent off until the pressure decreased and that the vented gas would safely dissipate out on the highway. The hissing didn't stop until the tank was about 1/4 full, it was a long drive to our final destination with no camping as planned. Dealer, after several pleading phone calls to Jayco, offered to replace the pressure relief valve. Tech found and fixed 2 other propane leaks in the process. Whew! What a trip.

[herewego]

On the side of most fill valves,there is a small screwdriver slot ,that is what they open sometimes when filling,when liquid comes out it is full,its called the 80% Valve ...
Just so you will know propane expands 270 times its liquid volume when it boils off to gas, liquid propane does not burn ,its the gas/vapor

[DocBrown]

This is one of those things that's not lawyer speak, kind of like the warning to not smoke near gas pumps. It's the physics of gases. And it's dangerous to ignore. Because people ignored this so often they sadly had to make it a federal law.

[troutslayer]

Originally Posted by redcedar

Good to know. Is it true you can determine the propane level by tapping a coin on the side of tank from the top down and listening to the sound (pitch) change?

Don't know about that. I pour hot water over the side of the tank, then feel where the tank temp changes from warm to cold...that would be the propane level.

[Seann45]

It has an OPD (Overfill Protection Device) inside the tank and cannot be filled past that mark..