Chimney Suggestion Needed.

billinmass

We have an oil fired boiler with an exhaust fan. It all works fine but the exhaust is on the northern side of the house and our bed room is next to that area. During the winter I can at times smell the exhaust in the bed room and areas near that.
I would like to put in a chimney to vent the boiler above the area. Can the fan be used to push the air up the chimney?
The roof on that side of the house is a single story but the house is two story so I am concerned that the chimney would need to go up more that 3 ft above the roof to vent it above the second story to work well. I don’t want to put the exhaust into the second story rooms.

Any thoughts on this?

Bob Harper

You cannot pressurize any natural draft chimney or vent. You can have a pro lay it out and install a UL listed insulated factory chimney, either up through the house or up the outside. The code requires it to extend a min. of 3 feet above even a flat roof plus 2 feet above any point within 10 feet measured horizontally. You can encase it in a 'chase' to make it more aesthetically appealing and shelter it from the wind & cold a little. Now, as you observed, if the chimney does not extend above the 'thermal envelope' of the building, the house may function as a better chimney resulting in backdrafting, which is probably why it was installed as a power vent in the first place.

They do make fans to suck it out vertically but you'll still have the issue of the fumes.