Pellet stove question or fireplace damper issue ?

[bigdog]

Pellet stove question......
Or maybe more like a fireplace damper issue?

Have a serious issue with a draft coming from my Napolean NPI 45 pellet stove. First of all, experiencing this issue when the stove is "NOT" running !
Draft appears to be coming from bottom of stove.

Some background......
This is the first season using a pellet stove in my existing brick clay lined fireplace. I had a chimney & stove professional install a 4" stainless steel liner from top of chimney down through the chimney damper. Actually the chimney damper-baffle was totally removed. A chimney cap with flue cover was installed at top of chimney, which covers the entire top of clay lining.

I pulled off the decorative backing plate cover, which attaches above the pellet stove (which covers the opening to the fireplace), to look up inside the damper. Much to my surprise 'the Professional' did not install any type of cover in the flue damper around the stove pipe. The pipe was just shoved up the damper, to the top of the chimney. So consequently, what I have here is this huge open space in the damper around the stove pipe.

Could this be causing the draft?
If so, why would the draft be coming from the bottom of the stove?
Does the stove draw air into the stove from the bottom?

Thanks for your feedback, greatly appreciated !

Bigdog

[thinkxingu]

Not having a plate to seal off the chimney where the damper was is not uncommon--there are many different beliefs about this regarding lost heat vs. creosote build-up from a cold pipe causing condensation (non double-wall pipe).

If the chimney cap was sealed correctly, and the pipe is secured to your stove well, and you're getting a draft it's because you have negative pressure.

I'd probably call the installer to give him/her a chance to fix it before doing anything else--might be something simple they can remedy.

[bigdog]

Thanks Thinkxingu for the info...

I believe the chimney cap/plate to be sealed very tightly, although have not insepected myself. Will have that inspected in the summer when I get chimney cleaned.

I was also told by another that I might have a 'negative pressure' situation in the stove room, as 'lower level floors' are more prone to being in this state. The stove is on the fisrt floor of my 2,000 ft colonial built in 1999, and is well insulated.

On that note, how does one offset 'negative pressure' in the house?

Last, was also told that one reason for the draft may be air from the flue going through the stove and out the 'air intake', which is near the bottom of the stove ? This seems like a possibility.

Thoughts on all above ?

Thanks,
Bigdog

[DickR]

Your house may be well insulated, but still not very air tight. When the stove is not in operation, the chimney, through the stove, is just another low-level air leak, like a gap under a door, leaking heavy cold air in low and displacing warm interior air up higher, such as through air leaks into the attic. One symptom of a leaky (typical) house is that the interior air gets dry from overventilation in winter, to the point where you'd like to run a humidifier. Another would be the formation of ice dams and icicles at the roof edges, from warm interior air leaking into the attic. Air sealing will help this.

A good place to ask questions about your stove installation would be in pellet stove subforum here: http://www.hearth.com/talk/

For air sealing the attic floor in a leaky home, a good starting place is here: http://www.greenbuildingadvisor.com/blogs/dept/musings/air-sealing-attic

For more a general list of "how to" information, including air sealing in general, see http://www.greenbuildingadvisor.com/blogs/dept/musings/how-do-everything