Venting of On-Demand Water Heater

[Matthew M.]

I am trying to install a Richmond "on demand" gas water heater to replace an existing tank-style unit (need to install a self-venting unit because cannot vent all the way to the roof). The walls in the home are brick, though there is a boarded-over window with a dryer vent a few feet over (this is being installed in a basement).

Question is, using manufacturer's vent line (as required), can I vent directly out the side of the building, either through the plywood "window" (maybe converted to cement board or a similar material) or through the brick (just a bit more work). This appears to be fine or the water tank, I just want to be sure about Chicago code.

Either way ("window" or brick), if I do this the vent will come out of the house about a foot off the ground, facing out to a walkway between two homes (typical Chicago lots). Any advice on if this would be proper will be GREATLY appreciated.

[Markus Keller]

It is possible to vent compliant out the side of a house but it is very difficult and usually not compliant. This is due to a combination of sidewalk clearance, door and window clearances.
The revised venting Code was written, at least in part, to deal with the common complaint issues related to people venting gas appliances into gangways and causing problems between themselves and their neighbors.
If this gangway serves as a walkway the vent has to be at least 7' off the ground. Once you do that it is almost impossible to provide sufficient clearance to windows. The Code was written, in part, to essentially but without saying so force people to vent to either the front, back or roof.
With a furnace you could make excuses based on the idea that the furnace won't be ON, when windows are open. Since a water tank is ON, year round that excuse doesn't work.
I suggest you reconfigure your installation.

[Matthew M.]

Thanks, Markus. That's super helpful. How far from the nearest window do I need to be?

I ask because I can run the vent up through a chimney and out through the wall about seven feet up (but not all the way to the roof because the chimney was capped at about 9" long ago). The only nearby windows are two that do not open (just small glass windows that cannot be opened).

Thoughts? Again, thanks VERY much for the expertise.

[Scott Patterson]

I just want to be sure about Chicago code.

An envelope of money I have heard works well to insure items meet code!

[Jerry Peck]

Start by getting a copy of the MII (Manufacturer's Installation Instructions) and review their venting requirements and limitations, then compare those to the applicable Chicago code and the most restrictive of the two would take precedence.