Your 500 gallon tank worked. therefore I see no reason that you can't run on a 100# bottle.
-pat
.............did you read,,what crappiekeith wrote??? when it gets cold enough,,the propane,,wont gas off quick enough for the flow for a furnace,,and the burner,,and maybe even the pilot will go out....................in iowa,,even the coldest weve ever had,,never had a problem with a 500 gallon. seemed to have enough "boiloff" area. but i wouldnt be too sure of a 100 lb...crappie said he used a heat tape..................[/QUOTE]
I did. I also had to sit thru a long boring class learning all about propane, how to fill tanks, etc. you can't change the laws of physics! a 500 gallon tank at 20 below is gonna have the same pressure as a 1# camper bottle. The only thing you change is the over all MASS of the thing. the 500 gallon tank is going to have more mass, and therefore take a little longer to chill down and lose pressure. At the store here, we run a Toyota Forklift. Used to be stored outside. It gets a smirch cold around here... not as bad as over there... but I know of several times when the truck would get here and I would be the one "chosen to be frozen" and unload the truck with that lift truck.
-25 F, and it started. The engine runs off of a 30 lb cylinder. Wasn't real happy about it, and the hydraulics were very sluggish.
before you drop the facts that it runs on a liquid line, and then to a regulator. The propane carburetor is warmed with coolant, but NONE of that is working when I stuck the key in the switch and cranked it. At -30F Propane would have 6.8 psi remaining. You crack open a valve, and the pressure in the tank drops which causes the stuff to boil off, and provide the vapor pressure you need. I don't know what the pressure drop would be even if it was half, the system should still work.
I think that getting a regulator with a larger btu capacity would be the hot ticket at low tank pressures. Larger valves would flow better, and maintain the necessary 11 w.c. that the furnace requires.
Flame me if you want. I still believe a 100# cylinder would work fine in this application.
-Pat