On Feb 13, 11:54 am, " wrote:
the BTU # is from the manufacturer, they vary from under 30,000 BTU to
75,000 BTU on my current tank.

I can't say that I know what the 41,045 BTU is in the calculation but
it can't be different for different gas burners because it's the same
number no matter what gas heater you use.

So it must be some kind of other "magic" number.