Just got a new 1.2 gallon tank with the new opd valve for my mr heater boat heater. My first tank was harder than hell to fill, we finally managed to get .8 gal in it, hook up the heater not enough gas flow to light it. So I take it back and get another, actually get a gallon in this one it was slightly easier to fill than the last. I hook up the heater it lights halfway I turn it up no change. These new tanks are a friggin joke, anybody else have problems with thiers.

have not changed mine out just for that reason, have heard of many stories about try ing to fill them pain in the a$$, what the reason for going to these new valves any ways, haven't heard of to many propane tanks tiping over lately, (say the last 20 years)

I've got the next size up, 3 gal or so, and it seems to fill ok, but I can only use 2 gallons of it and it loses pressure. Great, more weight, less performance, just like my Suzuki 4 stroke

I have had two new one gallon tanks, with no problems.They also run my Mr. heater. New tanks have to be purged before they fill them for the first time. It sometimes supprises that some of the people filling these, can even figure out how to put gas in there car. If your tanks have not been purged, I am sure that is your problem. You might also want to take tank and heater to a propane company and have them check it out.

I have 2 OPD tanks, a 2gal and a 5gal. The 5 I use on the bbq and the 2 on my boat heater, I've had no problems with either in over 1.5yrs of use. The only reason I can think of, as to your problem is that whoever is filling them isn't purging the air out before filling. I had the same problem on an earlier tank used for my crab cooker, the station didn't purge the tank before the first use, took it back had it purged, problem solved.