They generally use a calculation of the degree-days of heating necessary and then fill it up to about 80% based on that.
I have it done every few months.
k2dave, look for a percentage gauge somewhere near the valve system. That should measure it up.
And I always thought it was a float…but I’ve no way of knowing if I’m right.
Update- The hot water method (and just hot from the tap - not boiling) worked great, and it also worked for the kerosene tank as well so I don’t have to open it to check the level anymore. Thanks for this simple solution.
As for a gauge there is none. I confirmed this with Agway. When they do fill it they have a release valve that they open ever so often while filling. This valve is attached to a tube that extends down into the tank maybe a foot or so. When gas only excapes the tank is not full. When liquid comes out it is full. Very primative and wasteful - I was disappointed when I found out too.
BTW I estimated the tank was 1/2 full w/ the hot water, It was refilled this weekend and took 39 out of 100 gal. The level seemed to be at the 1/2 point on the tank but I think I didn’t take into account the extra room needed at the top.
That’s exactly right. A propane tank is only at 80% capacity when it is “full”. The extra room is needed for the liquid to turn into a gas before leaving the valve. As far as the bleeder valve, a very small amount of gas is wasted while filling. I work at Ace Hardware and propane tanks on RV’s work the same way. The amount of gas released while filling is minimal once compressed into liquid. We have a 1000 gallon tank at work and AT THE MOST maybe 1 gallon is released while filling.