Another propane question

All propane tanks have a "tare weight" or "T.W." stamped on the collar of the tank. For a grill sized tank you simply calculate the tare weight + 20 lbs, and that's how much the tank should weigh when it's full. Most 20 lb tanks have a tare weight of +/- 17 pounds when completely empty.

The filler sets the scale to include the tare weight of your cylinder (varies a little; it's marked on your cylinder as TW), the weight of the propane when full (your WC X .42), and the weight of the filler's hoses.

For a TW=18 cylinder on our system, the scale would be set to 44 pounds. It'll vary some, depending on your filler's system.

Lynn

Counting the weight of the hose it may or may not have filled it. Odds are I'm betting you filled at a place that charges by the tank which gives them incentive to short change each tank a pound or two. To make sure you are getting your money worth, always fill tanks that charge per gallon and make sure they reset the meter to zero.

The OP was about setting a scale, which involves the safety of propane. Essentially, then, it is a procedure to make sure that a given cylinder is not overfilled (a dangerous condition). It is simple mathematics: the weight of the propane plus anything else that presses down on the scale (the cylinder itself, the hoses and valves -- 6 pounds in our set-up).

Charging for propane is completely separate and certainly does not involve considerations of safety. I suppose there are places that charge by the pound, though i haven't run across any personally. Most places will charge by the gallon (as i do) or will simply have a flat charge (which can be a bit of a rip off, imho).

Note, then, that if we were effectively to underfill a cylinder, then it would also merely involve fewer gallons of propane and, as a result, less money on the sale.

Lynn

Just ask him to open the spit valve and verify. If they charge by the gallon and no minimum charge then all is fair but I understand wanting it completely filled to normal capacity.
If it seems short I would go elsewhere next time.

Opening the small valve is a safe method to avoid a dangerous overfill, but it is either discouraged or disallowed in some states: It inevitably releases some liquid propane into the environment.
Lynn

But if they are selling "flat rate", by having a lower fill poundage than actually required, they save a few pounds of propane on every fill. If they do that on 100 tanks per month, they make a few hundred dollars.

Granted, most are honest but there are the few who want to make the extra buck at the customer's expense. Just enough one always needs to be on their tows and watch out for the not so honest folks.

Yep, a flat rate is a disadvantage, especially if there is some residual propane in the cylinder.

But the real rip off, i think, is the propane exchange. If you read the plastic sleeve, it generally reads 15 lbs. net weight. I guess it takes a genius to read the WC number on the collar and multiply it by .42. And then the genius knows that there is a short change of 5 pounds.

Lynn

a propane bottle that will hold 47.6 pounds of water will hold 20 pounds of propane. This indicates that the scale needs to be set a little over 38 pounds (20 lbs + 18 lbs = 38 lbs) to obtain the weight of the bottle when it reaches its allowable capacity.

daily double wrote:
I went to fill my 20# bottle just now and the guy set the scale at 39 lbs. I told him I didn't think that would fill it but he said it would. I needed propane but I think he was wrong. Opinions?

Propane 101 -----cylinder filling

So........
How were you charged ----- by the gallon, by the weight or by a flat charge?

and if by gallon.......how many gallons? 4.7 gallons


What say you?????

I don't think anyone gets 20 lbs of propane today. The mandated opd valves take up some of the tank's volume.

It's also been many years since I had anyone fill my propane tanks by weight. The suppliers I have used at home and away from home all use the little bleed valve to know when the tank is full to it's safe capacity.