water heating venting

This state water heater, natural gas, 1998, has a vent through the sill plate to what looked like a gas fireplace type termination. but it appears to me from the size that someone just brought the old gas chimney down to the water heater. It doesn’t seem to have a power vent.

Anyone seen one like this? Should it have a standard open draft chimney fitting and go above the roof?2008 3 13 cobb and montfort 005.jpg

Ted, I have never seen this setup.
I highly doubt that heater is intended for sidewall termination.
The lack of a draft hood makes me question how well it drafts to the exterior.
Consult the mfgs. documents or rep.

Without a draft hood it would vent “too well” to the exterior on certain days. The draft hood performs the same function as a barometric damper on an oil fired appliance…reduces overdraft on windy days. Overdrafting sucks exhaust gases out of the appliance too quickly and they don’t give up the amount of heat they should to the intended function of water or air heating…thus the appliance efficiency drops.

But unless this unit is certified for sidewall venting and that is the approved vent system, all installed properly, some yahoo is putting a family in danger.

A natural draft appliance WILL NOT vent properly without a draft hood. This installation is wrong, no matter how you look at it.

Brian. I wasn’t very clear in my draft statement. My concern was indeed that ther would be draft problems resulting in flame lifiting from the burner. In short, it’s a mess.

A DIRECT-VENT SERIES does not need a draft hood…

It has a Direct-vent design that draws combustion air from outside
the home ensuring a sufficient air supply for proper heater operation.

The "Coaxial” direct-vent system combines venting and air intake channels in a single pipe, requiring only one opening in the outside wall.


Some direct vent types have draft hoods.

I never said they didn’t.

In any case, the vent flue appears to be too big for that size water heater.

Ditto, no draft hood, side vent, etc.

DIY special, always dangerous :shock:

A close-up pic of the outside vent cap would help. It could be drawing air thru the outer lining as proposed already. Page 3-5 of this manual shows a DIY installation.



A direct vent is not a natural draft.

Where did I say that it was?

I don’t know of any Direct-Vent Water Heaters that are not induced fan forced. They also have limitations on elbow design and length of total H/V run.
Your pic, and unit shown just can’t be legal/safe.


Bradford White do a direct vent water heater without a power vent. As proposed several times now, it could be drawing air through the outer lining of a dual-lined flue.


I’ve seen a fair number of BW - Water Heaters using Nat.and LP gas, and I can’t say I’ve seen a sidewall vent model that wasn’t power-assisted. Maybe it’s just a regional thing, maybe I’m forgetting.
I understand the concentric vent pipe design, used occassionally on 90%+ condensing type furnaces. It’s just not the choice in this area of the country. That being said, I will stand corrected, if you’ve seen one. I’ve also seen Rheem and State Ind. with sidewall vent design, again they all seem to have power-assist. Good info., I’ll check it out.


They do exist…

Here’s my very own personal direct vent water heater with NO power assist…


Direct vent appliances, in most cases, include sealed combustion chambers. To function properly, their exhaust vents should be sealed as well.

In the original picture, the exhaust vent connection to the tank does not appear to be indicative of a direct-vent appliance. So my assumption is that this is a natural draft appliance, in which case, a draft-hood would be required as an essential part of the natural-draft system.

Jeff is referring to this sealed combustion chamber…

See top right corner of image