Furnace/Draft Water Heater Combustion Air

[Markfothebeast]

Not related to a garage but rather our furnace room. I've been battling the furnace room since I moved in. The tight angle of the water heater draft exhaust has been causing the exhaust to get backdraft upstairs when the air condition unit is on. It sets off the smoke alarm but not the Carbon monoxide detector for some dumb reason.

The furnace exhaust and draft vent were on a tee which was blowing furnace exhaust at the w/h draft. After ****** knuckles and busting through cinder block I was able to replace the tee with a wye. Now when the furnace is running it aids in pulling the w/h draft exhaust up. However, I moved the water heater as close as safely possible to put in a flexible draft vent pipe which is still improperly angled and impossible to properly angle. The w/h no longer backdrafts unless the A/C is on.


The furnace room is in the basement and is enclosed with cinder block walls on 3 sides and a 2x4 wall on one. The basement ceiling is a steel frame (mobile home chassis) with a drop ceiling in all rooms but the furnace room. The backdrafting floats over the drop ceiling and makes its way up the stairs.

Our LPG furnace and w/h both draw combustion air from the home. Is it at all possible to seal off the furnace room and cut a combustion air vent into the exterior cinder block wall to allow cool air to be drawn in instead of sucking in recycled air (and possibly pull air from doors/windows/etc)?

*Photos coming soon

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[Fixin'Stuff]

Our LPG furnace and w/h both draw combustion air from the home. Is it at all possible to seal off the furnace room and cut a combustion air vent into the exterior cinder block wall to allow cool air to be drawn in instead of sucking in recycled air (and possibly pull air from doors/windows/etc)?

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How old is this house? Makeup air has been a requirement for all fuel-burning furnaces for many years. An HVAC tech will probably be along shortly to explain how to properly size the fresh air duct and what type of damper to use so that you don't have cold air just dumping into the basement all winter.

 

[Markfothebeast]

1950-1970 is our estimate. The deed doesn't state the age of the home. It is a single wide mobile home on a walk-out basement foundation. The original wiring is 12-2 without a ground if that gives any hint (And we finally replaced the lug fuse box a month ago).

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[LS6 Tommy]

What do you mean by "back drafting"? The furnace exhaust should not have any flow out of it during normal A/C operation. If you're getting flow out of the furnace smoke pipe down the water heater smoke pipe it may be due to a bad heat exchanger in the furnace.
Makeup air is not a requirement but separate smoke pipes is. You can't tee or wye two pipes together. You also cannot get combustion air and return air from the same room.

Tommy

 

[Markfothebeast]

The furnace is not backdrafting. It is the water heater. The "furnace room" houses both the furnace and water heater. The wall A/C unit upstairs overcomes the water heater draft and draws the smell/fumes out from the water heater draft vent. My only real option I'm thinking is to run an entirely dedicated vent directly to the roof for the water heater and disconnect it from the vent it shares with the furnace.

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[Rookie2]

Bite the bullet and buy a power venter or a power vented water heater. Carbon monoxide is a silent KILLER !

There is no guessing allowed, you may kill yourself if you like but it's inexcusable to have others in your home.