Outdoor air vent

Drew_6

I have an older gas hot water boiler (1950's) with radiators. I've tried to make it efficient as possible by adding an automatic damper, outdoor reset, and running the circulator continuously. I've also added insulation to all the outside walls and attic and "tightened up" all the air leaks in the house (5,000 sq. ft) including the basement. My question is should I add an outoor air vent that runs from the outside of the house to the boiler burners? I'm thinking that the burners will burn more efficiently if they have an outdoor oxygen source. Also, if I do this, how big should the vent be? The stack vent pipe is 8 in. in diameter. Thanks for the great info and help!

john@TR

If you tightened the house up that much an outside air source for combustion is more of a safety issue than a combustion efficiency one. Go to http://www.fieldcontrols.com/cas.php and read about how to size the set up you need.