Clearance - Top of furnace to ceiling

[mattinpa]

Here's my predicament. My basement gets water. I would like to elevate my wood furnace off the floor at least 6-8 inches. From
basement floor to ceiling is only 6 feet, with more between the floor supports (roughly 6 more inches.) Is there a minimum spacing I should leave between the top of the furnace to the ceiling? Furnace is 36 inches tall.

 

[stee6043]

What kind of furnance and what kind of clearance does the manufacturer recommend? Does your hot air come off the top of the unit? It sounds like you'd only have roughly one foot of clearance left if you lift it up 8". That's not much room to pipe/plumb a unit. I'm betting you're not going to want to be that close to the ceiling....

 

[mattinpa]

It is an add on furnace. Englander 3500. Yes the air comes off the top. If I lift the 36" furnace 8" that leaves me with between 28" and 34". The triple wall out to my chimney will be at 34" clearance between two truss, and the duct into the plenum of my existing furnace will be 28". Not sure what the manual says. I am at work and things keep poping into my head.

 

[stee6043]

I think you're clearance will depend only on the flue. They suggest 18" to combustibles for the flue. Above I was figuring it would take you a foot to make the turn but perhaps that was conservative. If you can maintain the 18" I think you'll be good to go...

 

[mattinpa]

OK. you bring up a good point. I was planning on running triple wall stainless out to the chimney. I was going to run it directly along my ceiling. Maybe 1" clearance.
I know with single wall this is a no-no and should be dropped 18 inches from my ceiling. But I'm using triple wall from furnace into flue. Same concerns?

 

[applewood]

In canada after flue clearance your two other concerns would be min 6 inch clearance (or heat shielding if you don't have 6 inches) for the first 6 feet of the hot air plenum and no boxed joists for your cold air returns.