Wood Stove in "two-suite" home

Our home in NW Washington was just completed. I'm having occasional weak draw and have noticed smoke exiting a joint in our double-walled connector pipe between stove and ceiling. Only noticed this for a few seconds on two occasions after 15 hours of stove use. Stove pipe above roof has height/location to code. Air return for the furnace is at least 25 feet away from the stove. Stove has external air source pipe.

Our kids and grandkids live in one wing (2600 sq ft) with my wife and I ( grandparents ) in an attached apartment (1200 sq ft ) , separated by an exercise room. There is a central geo furnace with air returns in both wings but thermostat only in the main wing. Doors between wings are kept closed.

We had a new HearthStone Tribute wood stove installed in our wing. I'm trying to figure out how to set things so we don't have any smoke drawn into our living room. The heating company installed a "damper" switch which if used would prevent furnace air from entering our wing, but not block the air return. I'm reluctant to use that ( or block the air return ) for fear of damaging the central furnace. Its not clear to me how blocking furnace flow into our wing would improve stove draw.
http://www.hearthstonestoves.com/store/wood-products/wood-stoves/tribute-soapstone

I'm considering some high-temp stove cement on the leaking joints, but realize good draw is the real solution.
I don't understand how double-walled pipe ( air gap between pipe and liner ) can leak that way anyway.

One thing we've learned is to crack a window if turning on the kitchen stove vent fan or bathroom fan. This is a tight house and the external air source on the wood stove can't keep up with furnace draw plus vent fan draw.

Jags said:

Consider increasing pipe height or maybe an OAK for the stove? In a tight home you may be dealing with negative draft, and it sounds like you are aware of that because of the "crack the window" comment. Does cracking a window help with stove draft?

Click to expand...

The stove has an outside air kit. Cracking a window does seem to help. In our previous home we just didn't use the central furnace when running the wood stove because the furnace air return was even closer to the stove than here. In this case we don't control the furnace so can't turn it off.

Jags said:

A cheap method to test the stove pipe theory is to add a section (or two if needed) of the snap together 6 inch stuff for ductwork to the top of your stack. I personally used this method to confirm that a 2ft addition to height is exactly what the doctor ordered.

Click to expand...

Good idea Jags. An addition like that might require paying the contractor again since additional bracing might be needed.

Before getting on the roof or hiring someone, I want to explore a few other options such as shutting off the central furnace air return to my side of the house ( have to determine if that would damage the furnace ). I also see that the Selkirk DSP double-walled stove pipe does not have 3 screws per joint in all cases. http://www.hardwareandtools.com/imp...170-stove-pipe-screws-hex-12pc-fjca-0009.html
Those screws appear to be 1/2 inch long which I'm thinking is too long and would hit the stainless inside liner.


[/IMG] [/URL]

[URL=http://s145.photobucket.com/user/2020indianrock/media/HomePhotos/20141231_113946.jpg.html][/URL]

The supply damper hasn't been activated yet -- hvac guys showed up with the wrong transformer. Mainly what we notice is a smoky smell when we come into the living room in the morning. So typically the fire died out overnight and with the furnace running a lot now ( 20 degree weather at night right now ), the furnace is drawing air from around the OAK fitting on the bottom of the wood stove. The smoke from the interior pipe joints was a one time thing so ignoring that for now but may want to seal those joints.
No leakage from chimney outside the house -- I have to keep my terminology straight.
If I open the stove door slowly to add wood to an existing fire, I usually don't get any blow back whether the furnace is running or not. Now turning on other vent fans like in the kitchen is another matter and we won't do that without cracking a window if the furnace is running.
Closing off the air return to the furnace is a big deal in my mind -- can't do that until convinced it won't damage the furnace.
As far as that supply damper, I honestly don't see how it helps unless it somehow reduces how much air the return is pulling.
When I open the bedroom door into the living room I can feel resistance when the furnace is running, so its powerful. ( air return to furnace is near living room but 20 ft from wood stove ) Our kids' wing in the house, on the same furnace system, is twice the size of ours.

Reducing or shutting off the return air might damage the furnace so not sure I can do anything there.
I think I've tracked down the source of the "smoke smell." It's coming from joints in the stove pipe between stove and ceiling after the fire has died out and the furnace is running. So, we need high temperature stove cement applied inside the joints along with the full compliment of 3 screws per joint.
At those times, there is no detectable actual smoke and no smell from the stove door or the area around the outside air source under the stove.

My intent is to not pay the contractor who installed the stove pipe until he applies the cement and missing screws. $750 for the pipe etc from stove collar to ceiling.

I'm working my way through this posting.
https://www.hearth.com/talk/threads/outside-air-kits-do-you-recommend-them.1929/page-3

We're learning as we go and I really appreciate all the input here. Yesterday I bought a manual log splitter and then ran the stove with the much smaller "re-split" logs. I was able to get at least four of those in the stove and burning really well. The stove door was left cracked about 1/4 inch. Opening a window or having the furnace running didn't seem to make a difference. When we went to bed I locked the stove door shut but left the air control wide open -- and -- left the bedroom door open. The bedroom/walk-in closet/master bath end of the house is probably half our square footage.

This morning no smoke smell and sniffing right at the stove pipe joints I detect mainly cool fresh air. They say if you change two things and get different results you haven't figured out your problem. But it is progress.

So I may have introduced creosote into the pipes during our first few days of poor burns ( starting the first fire with lots of leftover cardboard was probably stupid. ) Last night's good long burn seems to have cleaned things up.
I see this morning that even with the door shut the fire completely burned down to ash last night.

So now we may just be left with the need to keep the stove door cracked longer than expected to establish a decent fire. This suggests the outside air kit is part of the problem -- it does seem that a 3 inch supply pipe would have trouble keeping up with any sort of decent draw in a six-inch stove pipe ( not really six I guess since double-walled ). The thermometer I hung on the pipe last night about two ft down from the ceiling reached 100F -- we want to put blinds along there but it does look like the blind near the pipe would only be six inches away so probably won't be able to do that.

Since the furnace return is drawing air out of the pipe joints when the fire is dead, I'm now not sure about the wisdom of putting furnace cement in those joints.

Although related, the two families in the two wings of this house want privacy. The exercise room joining the two wings has doors which are kept closed and locked. I have four things in mind at this point. 1) Get more CO detectors, 2) prove to myself I can close off or reduce the furnace return without damaging anything, 3) seal the existing DSP or replace it with better quality than the current Selkirk, 4) lastly, sell the wood stove.

This is a brand new house. I'm thinking that even if the hvac is perfectly balanced, the air return has to get air from somewhere. If it can't get enough around doors/windows or from the OAK ( the fittings on the bottom of the stove aren't perfect by any stretch ), then it would have suck it down kitchen/bath vents or... ?? ... from the stove joints?

Ah, balanced. I think I see what you mean now. If the air being blown into the room doesn't equal the air being drawn out through the air return, it has to pull from elsewhere. Plus, our air return is only ten feet from the furnace room whereas the other two returns in the other wing are farther ( one a lot farther away ) But again, imperfect systems may be common and DSP makers don't want to be sued out of business.

So if the cool, seemingly fresh, air being drawn out of the pipe joints was actually mixed with air from the inner liner, you could have a very common dangerous situation. This is what makes me think the innner/outer liners have to be isolated.

Our wood may not be seasoned enough, but it doesn't sizzle as if wet. It may take a while before I locate a reliable source in our new town. We finally closed off the air return in our apartment. The main wing has two and our HVAC guys said it should be fine.
This is a soapstone stove ( hearthstone tribute ) so I'm having to learn how to feed and run it -- apparently these suck a lot of heat into the stone for a while and aren't intended for occasional burns.