Have to get humidity down: glass tops or canopy?

[Delphinus]

Originally Posted by wickedfrags.com

Fascinating about that code issue and the furnace interlock - any idea how many CFM this relates to?

I find sometimes that "code" must mean "secret code" because it can be a challenge trying to pinpoint what's in code. On the Calgary municipal website though I found a PDF document for "site supervisors handbook for new home inspections" that has this to say:

HVAC Inspection

• Heating appliances operational
• Fresh air intake requirement, grills, registers, and thermostat installation completed
• Principal exhaust fan interlock completed
• All exhaust fans over 180 CFM – require interlock with furnace blower or separate make-up air
• All exhaust fans over 300 CFM – require that the extra make-up air and may require pre-heating before entering furnace duct work depending on site conditions
• Auxiliary systems (i.e. heat recovery systems) in place must be complete and operational
• Hydronic heating systems (if installed) must be complete and operational

Edit: forgot to post the link - here: http://www.calgary.ca/DocGallery/BU/...s_handbook.pdf

I've never quite figured out if code is national or regional or if there's two and regional usually exceeds national standards, or what. But I imagine in this case it will be pretty close to the same in most if not all places. So there we go - looks like 180cfm requires interlock with furnace, 300cfm requires HRV. I did find another site where it was mentioned it's more about not having exhaust gas backflow down the exhaust chimneys and not so much if your furnace has a incomplete combustion or whatever it was I first thought.