Furnace in Hallway Closet

What are the combustion supply air requirements for a closet unit. This us a hallway closet not a bedroom. Has exterior ventilation but no exterior air source. Door is louvred. Is this beyond the standards or is there a rule? I tried to look up the model number but Bryant’s website said no matches. I’ll try again when I get home

The data sticker you posted is for the A/C not the furnace. The data plate for the furnace would be inside the unit or on the side. It will have the correct information you need for research. Looks like an induced draft high efficiency furnace from the picture.

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@mdurante has it

#1 is intake or combustible air
#2 is exhaust

Looks like an older home with a newer system. Drawing air from inside the home can cause problems depending on how tight the home is and what other ventilation is present. This would require additional testing outside the SOP.

However, unless you see indicators that a problem exists I would move on barring the manufacturer having conflicting requirement.


Here is an earlier discussion on this topic.


Sounds good. Home was not very tight based on what I could see and feel. You can feel it in a lot of these garages nowadays.

Recommend combustion air piping be installed into the room or direct into the furnace if there is room.

Ok, why would you recommend that?

Yes! Why? …

Curious what indicators you would be looking for. I’m just trying to flatten the learning curve.

This is clearly a “confined space” (less than 50 cubic feet of space per 1,000 BTU per hour of aggregate input). Assuming the louvered doors are kept closed, do the openings in the louvers provide adequate combustion air? From Internachi - “Combustion air opening fitted with louvers, the inspector should note that metal louvers obstruct about 25% of the opening, and wooden louvers obstruct 75% of it.” (those look like wooden louvers) “If combustion air is inadequately supplied to a gas furnace, carbon monoxide will likely be produced”.

Flame that is yellow or orange, sooting, flame-out etc. Which is really hard to do with the doors closed :smile: I would also check the water heater for similar issues.
If you want to calculate the combustion air required for this unit, you will need more information than provided. In my opinion, those louvered doors offer a lot of combustion air, especially compared to the 12" top and bottom vents which are common.


Thats is what I was thinking.
Thanks for the add’l info.

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I agree Brian. My first thought was recommend external air but without having more information I can’t justify it. Especially as calculating these things is beyond the standards. I closed the door and started it up and then ripped the door open and looked at the flame. There was no orange flame, only a minor flicker here or there which is common on startup. Not super scientific but I made an effort. I also agree the louvers are better than the bottom door you often see.
My instincts are that it was acceptable or at least enough for me to not have to recommend further evaluation. It’s not our job to just blanket recommend professionals for everything under the sun. I like to know enough to say it’s ok when I can.

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