Basic flue temperature question from newbie

[DeanBrown3D]

Hello all,

After having installed my charmaster whole-house furnace (see other thread) I have a nagging question on my mind: I'm supposed to keep the flue temperature above around 200 degrees to stop creosote build up, and the flue temp is hotter than that all the way up to the automatic barmometric control (just before it enters the chimney), where it then drops down (logically) way below that temp. Is that right? Am I missing something here - adding the barmometric control means that after that point in the chimney, the flue temp is too cool?

Thanks for any insight.

Dean
(ps its a SS insulated chimney, through center of house starting from basement.)

 

[Eric Johnson]

The chimney should be hot or you will get creosote accumulation. If the spec is 200 degrees, then it should exceed that all the way up to the top of the chimney, I believe.

I don't understand why you have a barometric damper on that furnace. Is it multi-fuel?

 

[DeanBrown3D]

I don't understand why you have a barometric damper on that furnace. Is it multi-fuel?

Nope - wood only. The instructions recommend a barometric control - I presume to reduce the draft through the furnace. It came with an internal butterfly valve, but my installer recommended the auto type, like the instructions suggested.

 

[Eric Johnson]

I don't know how you cut off the air supply with a barometric damper in the event of a chimney fire, but if that's what the mfg. recommends, then you're doing the right thing.

Nice looking install, by the way.

With a furnace I really doubt that your chimney will get too cool, especially if it's stainless steel. And if you have a catalytic combustor or a secondary burn scheme, you might not get much creosote beyond the pipe anyway. I was thinking boiler, not furnace.

Instead of worrying about it, just keep an eye on it for a week or so to see if your draft is affected, which would happen if a lot of creosote were accumulating. If that doesn't happen, then you're probably doing OK. After about a month, run a brush down the chimney (or at least inspect it with a mirror and a flashlight), to see what's happening. If it's relatively clean, then don't worry about it.

In short, don't lose any sleep over it, but be sure to keep an eye on it, especially for the first year until you become comfortable with the way it operates. Every installation is different.

 

[johnsopi]

My Yukon wood furnace came with barometric damper. I have to clean out that piece of stove pipe every 4-6 wks.

 

[Eric Johnson]

When I had a furnace, I just used a conventional manual cast iron damper and the combustion fan (or other conbustion air control) for draft control. Essentially, I operated it like a wood stove.