8 Inch Pipe?

[ScottLewis]

I don't want to sound like a newbie but there is a gal on local Facebook with a problem. She has a big old wood stove in the basement. 8 inch pipe stove. She bought it used and it had setting on top an 8 to six inch reducer. She is running six inch pipe vertical for 2 feet. Then out the window for a 5 foot horizontal run. Then a vertical stack 14 feet high. All six inch pipe. It won't draw. Local "experts" are saying to make the 5 foot run on a 30 degree angle running up. She's getting all kinds of advice.

I told her to simply replace the six inch pipe with 8 inch. What do y'all think?

 

[gthomas785]

Is it all single wall pipe going out the window and up?

Ignoring the fire hazard and creosote factory concerns for now... In reality it's probably not drawing because the whole thing is too low down to the ground. 14 ft elevation is marginal even for a warm insulated chimney. Depending on how bad the stack effect in the house is a setup like that will act more like a fresh air intake than a chimney.

Sloping the horizontal run will certainly help but might not do enough. Switching to 8" will allow more air to flow through the stack but might not increase the draft pressure at all unless she can make the chimney significantly taller and get it to retain a bit of heat.

 

[stovelark]

This is trouble waiting to happen. The stove won't draw- is this happening now? Most stoves won't draw well in warm weather. What should be done is 8" connector pipe going up and out to a Class A chimney. And certainly not 5 feet horizontal. She cannot reduce the stove output flue size with the piping. The basement will work against the draft too in a lot of cases. And of course clearance to combustibles (chimney connector pipe, Class A piping, the stove itself and any hearth requirements) need to be adhered to. Hopefully she can get the stove closer to the outside wall, go up appropriately and out with the piping. Don't forget good dry seasoned wood too to have a chance of success. Hope its a UL listed stove too, and the install gets inspected. Good luck.

 

[begreen]

We really need some pictures to see what's been installed. There are safety concerns here.
The problem of the size reduction may be compounded the long horizontal run and/or it could be negative pressure in the basement. Weak draft can also be because the flue is not getting warm quickly enough. Poorly seasoned wood can be a culprit here.