I'm piping a new tank for my oil furnace, and I've got a few
1) This is a two-line furnace. How is the second (return) fuel line
used? Does the furnace constantly recirc the fuel while running?
2) This is near Portland, OR. Typical lows in the winter get down to
mid 30's F. I have maybe a 50' run of pipe from the tank to the
furnace, most of it outside/above ground. Given the price of copper,
what's the minimum diameter tubing I can get away with? Can I use
smaller diameter for the return?