Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Replacing Natural Draft Boiler - What Are My Venting Options? (Toronto)

I'm looking to replace my boiler and I need some advice. I'm in Toronto, in an older (1940s built) house. My house sits on my neighbour's property line. My current boiler is in my basement and vents up the chimney in a natural draft configuration. It is common vented with my HWT.

Some contractors told me that the best solution (based on space constraints) is a direct vent configuration onto/above my neighbour's driveway. But I don't want the inherent liability.

See pictures (x3): <a href="http://imgur.com/a/u0gew">http://imgur.com/a/u0gew</a>

If I got a combi boiler like the Viessmann Vitodens 100, is there a way I could have both the intake and exhaust running up the chimney?

I'm trying to avoid intake coming from my basement, as I don't want to have to seal up my boiler room as per TSSA regulations.


  • SWEI
    SWEI Member Posts: 7,356
    Plenty of options

    Not sure what liability there is with the sidewall installation, but there are plenty of other options.  http://www.viessmann.ca/etc/medialib/internet-ca/pdfs/doc/vent.Par.99112.File.tmp/Vitodens_Venting_ii.pdf

    pp 55-56 shows what Viessmann calls a hybrid system that you might consider -- air intake on the sidewall and exhaust up top.  Not all mod/cons permit this layout, which is unfortunate, because it prevents a number of potentially bad things from happening.
  • boilerventing
    boilerventing Member Posts: 3
    Use Masonry Chimney for Intake & Exhaust?

    The Viessmann manual seems to suggest that I can run a single coaxial vent or two PVC vents through my masonry chimney chase for both intake and exhaust. Does that seem like a potential solution, or am I reading it wrong?
  • SWEI
    SWEI Member Posts: 7,356

    Yes, they do show both options, and in fact many mod/cons require intake and exhaust to be in the same pressure zone (altitude.)  I understand wanting to exhaust up top, but why not put the intake on the side wall?

    Coaxial venting is not cheap, but might save some labor depending on the building particulars.  I prefer separate intake and exhaust if there's room, as they're a bit easier to maintain and repair.
  • gennady
    gennady Member Posts: 839

    you can run centrotherm innoflue flex hose up to chimney, according viessmann manual and code requirements, and get fresh air from driveway http://www.centrotherm.us.com/news-and-events/innoflue-challenge/.
  • gennady
    gennady Member Posts: 839

    Viessmann does not approve PVC for exhaust.
  • VictoriaEnergy
    VictoriaEnergy Member Posts: 126
    Vent not allowed for saftey reasons

    1) Our inspector would not accept a vent terminal above a driveway as some dripping of condensate is normal and will create an ice slip hazard under the vent.

    2) You can't place a vent terminal on a zero lot line.  Now you might be in the set back 12" back, but the exhaust (and it's a sizable cloud) will likely create an objection with your neighbor. 

    Drawing Combustion air into a sealed combustion unit would be fine as long as there is no dryer vent, hot tub or pool nearby

    Centrotherm up the flue for a boiler with indirect is your best bet.
    Home Owners Please Note:

    You are receiving advice from some very skilled pros completely free of charge. One of the reasons I participate is to sharpen my own troubleshooting skills. So; did we get it right? I would be grateful if you extend this courtesy back by posting the final outcome of the issue you are inquiring about. Thanks
  • Henry
    Henry Member Posts: 996

    We in B149.1 have had many issues with venting sidewall. Specifically in new construction as some local building codes allow houses to be built with a few feet of each other. The code now states that the vent should not cause any damage or inconvenience to an adjacent property. 8.14.8 I would go with a Lochinvar or HTP product and vent with PVC in the existing chimney chase while taking air from your wall. There will be no plume and no ice on your neighbours property! Centrotherm or other polypro vents are more expensive than PVC S 636 which is an an approved product for venting.

    Voting member of B149 and 7 subs

This discussion has been closed.