Recommendations on Existing Wood Stove

If I can add my $0.02 to this., it seems like the time that I’m most concerned with draft is when I’m starting my stove. At that time, when it’s 30-50 degrees warmer in the house than it is outside, I want the small amount of heat associated with starting a fire to cause the gasses associated with combustion to exit my chimney instead of coming back into my stove room. So if at the 30-50° differential I can get a draft, I’m pretty damm sure that at a 1200 degree differential I can get a good draft and in most cases probably too much to let the stove operate wide open... so with that assumption, I’m probably going to need to reduce the primary air and may even need a pipe damper to control the draft... seems like someone is using Boyle’s law to develop a correlation that predicts success or failure of a chimney system regardless of the time of year that it is installed.., Not sure why this would be something to argue about...

 

My pipe was 94F on the surface the other day with an IR gun...200 just above the doors...forget to measure the stove top, but I still had draft. Although I am cheating...

 

The only draft specifications available are for a stove that is up to operating temperature and has the air wide open so hen we are testing a setup to make sure the draft is within spec that is how we test it. If that is right it should work during all stages of burn. The only question is how much heat will be needed to establish draft and do you need to preheat the flue to do that.

 

Yes in this case we are talking about a stove that may have to much draft though.

 

Ok. Didn’t know that. Perhaps that is why my setup performs better with an inline flue damper. Probably out of specs with my setup then. I’m just a wood hoarder... thnx..

 

Me too...
Saving my wood and burning coal. The wood may just be reserved for outside parties in the form of bon-fires. Lol!! At least it’ll be seasoning well for me for when I decide to burn wood again inside.

 

To much draft can cause serious problems as well. The problems are very different but can be just as dangerous.

 

To much draft with a coal stove can be extremely dangerous. That is why barometric dampers should be used with coal.

 

Too much draft certainly can be dangerous with coal.

Some coal stove manufacturers don’t require a baro...although it would allow for optimum burn as far as saving on coal usage. Hitzer actually do not require an MPD or a barometric damper, but leave the option up to the user and/or the installer. That straight from the man that owns the business. However, their manuals do give manometer parameters with which their stoves like to be run. As far as I know they may be the only manufacturer to give these sort of numbers although Keystoker, Alaska, Baker, and DS Machine may offer these numbers as well in their manuals, but I don’t know. My particular stove has a built-in sliding damper (does not fully close) and because it was also designed to burn wood I added an MPD in the pipe, but leave it open. Not all Hitzers have the damper, but all do not require either because of the bi-metallic. Dean said they are all designed to let the bi-metallic run the stove and don’t need anything else, but he also says the configuration of a home/chimney may alter this. In other words, his recommendations remain very flexible.

The bi-metallic does the work of the barometric, just on the other end of the system. However, the baro is much faster at responding to wind and pressure changes that may happen in the chimney.

 

Exactly, he likes to have a draft of more than 6 pascal at a 50* temp difference.

 

How are you guys dealing with this on new installs of wood stoves where a manufacturer may not recommend any kind of damper? Surely they give you some wiggle-room.

 

Yeah not all require baro dampers but if you talk to them most will recommend them. But if you also burn wood you really don't want one then. Every manufacturer I have asked has the draft specs available. But many don't publish them which makes no sense to me at all.

 

If the chimney is over 25' I always install a damper. And if they still have trouble controlling it I come back and test draft. If it is still to high I add a second or restrict the top.

 

What about wood furnace manufactures that require a baro? (and they even come with them)

 

Does this apply to summer time installations?

 

Restrict the top huh. How?

I mentioned restricting the top to some guys the other day as a question and they thought I was nuts. Now I know I am not. Well...I guess that verdict is still out unless you talk to my wife. Lol!!

 

I am assuming you mean -6. If so that is about -.024" of water column. Max recommended by most manufacturers is only -.07. I would be very worried about overdraft if it was that strong at 50 degrees of differential.

 

It doesn't matter when I install it. In almost all cases once you get over 25' you will have to much draft

 

A reducer at the top. Usually down to 5" sometimes 5.5 is enough. I like to avoid that though

 

I absolutely hate that. As someone who cleans lots of chimneys I can tell you almost every chimney for a wood burning appliance that has a baro is a mess. That dilution air cools the exhaust to much creating creosote.