On Fri, 7 Feb 2003, Eric Zeno wrote:

> Assuming the fuel has the
> same weight as water,

Bad assumption.  Gasoline = approx. 6 lbs per gallon.  Water = approx 8
lbs. per gallon.  (U.S. gallons)

> how high would it have to be?

Reaching back into my fluid power classes...

Pressure (psi) = height (feet) * density (lbs per cubic foot) / 144

Water is 62.4 lbs per cubic foot, so gasoline must be roughly 41.6.

Solving for height...

Pressure * 144 / density = height

So 3 * 144 / 41.6 = 10.4 feet

The bottom of your tank needs to be 10.4 feet above the heater for a
minimum of 3 psi.  The pressure will be a bit higher with a full tank, but
not much.  Anyone want to check my math?

             _ _
  __ _ _   _| | |  | David M. Brodbeck (N8SRE)              Ypsilanti, MI
 / _` | | | | | |  +-----------------------------------------------------
| (_| | |_| | | | @ cyberspace.org
 \__, |\__,_|_|_| "To the optimist, the glass is half full.  To the
 |___/             pessimist, the glass is half empty.  To the engineer,
                   the glass is twice as big as it needs to be."