Propane level

Dusty R wrote:
How much does the level of propane, in a tank, change with the change of ambient temperature? As the weather has warmed the level in our tank has gone down about 2 to 3% each week in the past couple of months. About a month ago I closed the valve on the tank, thinking there might be a small leak in the line, and the level still continued to go down. It's kind of hard to believe the tank leaks. A leak that small is hard to find.Dusty

Someone will chime in with the specs of % and ambient temperature and elevation regarding propane tanks.

Everyone I know that had that type of leak found it to be coming from the valve. Common failure.

Mine is leaking from the valve and once you find out what a 'by the epa' book repair is going to cost you, you will do this:
Crank the valve handle as hard as you can to the closed position. This usually stops it from leaking from the valve.

AND BTW....when you are looking to buy an RV?
Always turn the propane valve on and off.
If it takes two hands and a lot of force to get the propane tank valve open. It's a sign that their valve has a leak also! :W

If the actual level is going DOWN, it's not due to temperature increases.

Propane expands as temperatures rise.

How are you determining that the propane level is decreasing? Propane pressure is not relative to volume and while the pressure inside the tank may rise somewhat as a result of heat, you can not measure that.A pressure gauge is not very useful for much besides leak testing the system.

It's not a pressure gauge, it's a level gauge. In order for pressure to increase the liquid needs to vaporize, which heat will cause, more vapor less liquid, thus lower level.
I did turn the valve off firmly, still level went down, until this week.
I've had one in the past where the valve stem packing on that valve leaked.

Dusty

Owned and seen several where the valve stem packing was leaking
Luckly we do not yet have an EPA approved protection device requirement and you can open the valve fast to the end stop with out any issues other than stopping the leak.

Dusty R wrote:
It's not a pressure gauge, it's a level gauge. In order for pressure to increase the liquid needs to vaporize, which heat will cause, more vapor less liquid, thus lower level.
I did turn the valve off firmly, still level went down, until this week.
I've had one in the past where the valve stem packing on that valve leaked.

Dusty

Huh, No! As temperature rises the both the liguid state and vapor state expand in volume. Since it is a saturated liquid state in the tank the vapor pressure also rises. The end result is the liquid level will rise (it is non-compressable in this temperature range) and the vapor volume will actually decrease while pressure increases.

If your liquid level is going down with temperature increase it is absolutely a leak somewhere.

That's not what I really wanted to hear, but needed to know.
Is there a long term warranty on LP tanks?

Dusty

I doubt that the tank itself is leaking- more likely the valve or one of your fittings.

As for warranty: Never heard of such a thing as a "long term warranty" for propane tanks, but it wouldn't hurt to check with who/wherever you got it from.

We have a SeeLevel monitor panel. When the propane is at 80% the panel shows 100% which means the propane capacity is full.

26 March Arrived home in Michigan from Florida.
9 April panel read 59%
14 April " " 56% I turn off main valve on tank firmly
23 April " " 51%
29 April " " 49%
6 May " " 45%
14 May " " 41%
19 May " " 41%
25 May " " 42%

Could these different % readings be because of increasing ambient temperature?
It got up into the 80's for a couple of days then down into the 50's for a couple.

The mh is stored in an unheated, uninsulated pole barn.

Dusty

LP is a LIQUID in the tank. The temp will NOT cause a Liquid in a sealed vessel to go down or up. Temp will only cause the amount of PRESSURE to increase or decrease inside the vessel, but the liquid will stay static. There are NO floats inside an LP tank, so the Liquid will flow like waves if the vehicle is moving and this will cause the float to go up and down and the reading on the LP monitor will go up and down. OLD Georgia Boy motorhomes used to have a constant round gauge that was on all the time and when driving the needle would fluctuate widely from the LP moving in the tank. Drove some RV'ers nuts. Doug