Carbon Monoxide - Heat Vent Open Or Closed?
Here's the situation... We have a forced hot air system with a vent attached to the *return* duct that resides directly next to the furnace in the basement. I guess it is where the returning air finally filters through the furnace, because immediately next to this return duct is the filter, and next to that filter is the actual furnace (where the flames are). Additionally, when I put a paper towel next to the apparent return vent, it gets sucked up. So, I think that proves it's a return and not a supply. Now the issue... I think the duct should be *closed* when the heat is in use. My theory is that you want the return duct in the basement *closed*, so that no carbon monoxide lingering in the basement (if exists) would get sucked back into the system through the return and distributed throughout the home. She says that the Gas company was here to do a regular annual cleaning last week, and the Gas company said the opposite - to keep it the return vent *open*. I think the only time you want a return vent in the basement *open*, is when we run the air conditioning (same system), because cool air will be drawn into the return from the basement therefore supplying the home with natural cool air.
Answer:
I say you are correct. Return air duct openings should not be placed in proximity to the furnace, the water heater, or flue draft hoods which could under *some* circumstance produce CO. Because, as you rightly figured, the furnace blower would then aid in distributing the CO to the *entire* house.Well... even assuming that the problem is real, simply closing that vent isn't a good solution. If he doesn't like the return air vent that close to the furnace, he should either construct a partition between them, or extend that vent farther away, or both. All of which assumes that it's not supplying combustion air in the first place. First...if you have an exhaust vent from combustion material in the home...its not only not code..but stupid....period. Not trying to flame you, but I think we are talking about two different things. Now...if its a barometric vent, then, it wont pull back into the basement, UNLESS you have a negative air pressure situation there, and then, the vent will close itself... IF its an open vent, for venting of combustion gas, then you need to get that outside...period. If you think its possible that it is a barometric vent, or are not sure...let me know,and I can post a link with a picture of one, on my own system, and point out the return locations as well...that ARE in the same room..but so are plenty of combustion air sources.