On 10/3/2012 11:32 AM, Stuart MacMillan wrote:
> Problems like this are maddening!  Bad auto stop valve or bleed valve that
> doesn't vent are the only things that can prevent filling.

It's more likely that the tank simply needs to be purged of air, as
already mentioned.

When the tank has nothing but propane in it, it can be easily filled.
Pumping liquid propane in increases the pressure, and the existing
propane gas in the tank turns to liquid, making room. For a tank at 80F,
that pressure is about 130 psi.

If you try to fill a tank which has air in it, the air simply
compresses, and pressure goes up. New tanks are often shipped with
compressed air in them, so you can't push much propane in before the
pressure gets too great to be able to pump more.

Hence, the need to purge the air from the tank before first use.