I have a question about incomming air for my boiler's burner. It is a standard boiler with a down draft diverter on the flue. Above the diverter there is an automatic damper, which opens before the boiler fires. How much incomming air is needed? Would it be advisable to add an automatic fresh air intake somewhere in the basement? Maybe use a similar automatic damper as the boiler has now, wired into the existing damper so they open together. Cut it into the wall and put a little rain hood on it w/ a screen. What do you think? Is it nessasary? The house has been sealed up much better in recent years, so much of the natural air leaks of an older house have been sealed off. I fear the boiler draft causing negative pressure in the house which my draw fireplace smoke into the room (which seems to have happened before I started opening a basement window when I have a fire lit).

i have a white rodgers gas valve Model 25G53 Type 406. What can I replace this with, apparently it is obsolete.