ricks said:An option, I've read about on this forum, I think it may have been Eric Johnson that does it..............................is, if you're sure the fossil fuel burner isn't needed, disable it and plug the flue pipe to slow standby loses. Then if you run out of wood or go away or whatever, you can unplug the flue, flip a switch and let the fossil fuel take over. I think that would work especially well for someone that's around most of the time, like me. You could burn wood or not burn wood, keep the oil/gas boiler hot and minimize standby loses.
You can also use a motorized damper to open and close the flue automatically. A signal to start the oil burner triggers the damper to open, and a switch on the damper triggers the burner when the damper fully opens (thereby preventing the potential danger of the burner firing with the damper closed).
Joe