Fresh Air Flapper?

Found this at today’s inspection on gas furnace vent in basement. I’m not sure if the water heater used to be connected here, or if it’s put there to help the booster fan. It’s a flapper, so it opens when the heat runs and the vent blower kicks on. The vent doesn’t extend past the roof, it terminates at ground level, with the vent booster fan assembly just on the inside of the termination point outside.

Is this supposed to be for fresh air? I was concerned with possible CO.

Also, I’m not sure if the vent needs to extend past the roof line, since it has that booster fan on it?


Looks like a barometric damper. Probably a conversion from oil heat to gas and they never removed it.

Possibly, since the house is over 100 years old. Oddly, the vent pipe doesn’t look that old. The high efficiency furnace was installed in 2004.

I will recommend it should be plugged/capped.

Thank you Stephen

Michael, be careful just recommending it be plugged or capped. Shouldn’t the HVAC contractor make the call that a system needs to be modified.

Good point, Mark. Recommending how to do specific repairs/modifications may get doo-doo on one’s shoes that is hard to get off. :mrgreen: