Pipe damper setting question

[2broke2ride]

Do any of you with old non EPA stoves run your pipe damper fully closed? This is my first year with my old Shenandoah and I have been struggling to get what I consider enough heat for the amount of wood I'm going through. So tonight while playing around with it in frustration I closed the pipe damper all the way and turned the thermostatic draft up to 3/4 ( I normally run the pipe damper 1/2 and the thermo at 1/2 to get exterior single wall pipe temps of around 450 to 550) closing the damper got my stove too temp up to 700 while maintaining about 450 on the pipe.
This is the first time I have used stove top temps. With my old setting my stove top was only running like 50-100 degrees hotter than the pipe.
So is running with the damper closed ok? Btw this stove has no baffles or anything in it, just a steel box with a pipe hooked too it.

 

[bholler]

It might be ok if you have tons of draft are you taking the pipe temp before or after the damper?

 

[2broke2ride]

Pipe temp is after the damper............ So far this stove seems to burn through a crap load of wood for the amount of heat I get out of it............ Tonight was the first time since I started in October that I really felt like she was throwing the heat she should.

 

[bholler]

Well it is an old stove it is going to burn through allot of wood but if you can keep the pipe temp up that high after the damper with it closed all the way go for it but i would check the stack often till you are sure it is working ok

 

[2broke2ride]

Thanks for the advice, I'll definitely be keeping an eye on it until I'm sure it is ok.

 

[2broke2ride]

So I'm adding another question, does anyone here not bother to monitor flue temp on these old stoves? I have two different guys that I work with that have both been heating exclusively with wood for 20plus years. They both say to take my flue thermometer and throw it directly in the trash and just run the stove as hot as I need it to run. They say as long as nothing glows red I'm fine and that running if too cold is way worse than running hot. What do you experts say? I just don't wanna burn my house down but I want to be able to heat with wood exclusively.

 

[bholler]

I agree that to cold is worse than to hot to a point but it is allot better to know where you are before you cook your stove

 

[2broke2ride]

So do you think I should just forget about how hot the pipe is getting and move the thermometer to the stove top? How hot would too hot be on the stove top? This old stove is plate steel so I'm sure it can take plenty of heat.

 

[coaly]

A newer damper has very small holes along the shaft and can't be fully closed. You would only have the leakage around it. Older dampers have a metered hole in the center and may be close to what you need to control draft when the draft is strong enough. (The colder outside temperature, the larger temperature differential and the more it can be closed) I suspect you have an older one like shown below;



As far as not using a thermometer on the pipe; They are not accurate as far as inside flue temperature. That's what counts. They do give you a basis to calculate what you're doing. (like an odometer in your car doesn't give you fuel mileage, but you can use it to calculate your mileage) They are correct in saying "running too cold is way worse than running hot". Running cool causes creosote, running hot wastes fuel. So it's better to waste fuel than create creosote. That doesn't say much for running it efficiently. Wouldn't it be better to run the proper temperature? You only know that with something to give you an idea of what "too cold or too hot" is. Too cool is 250* in the flue - measured all the way to the top. That is the condensing point of water vapor in the flue allowing smoke particles to stick. More than that is waste. But you need a certain amount of waste to be sure you are above that critical temperature. There are too many variables to keep it precise and you would need to be adjusting it constantly. (which is what a barometric damper in a coal stove does, but can't be used on a wood stove in case of chimney fire) Once you know what a thermometer reads on the pipe when creosote forms (by checking regularly) you have an idea when you are forming creosote in the flue.

Post #4 in this thread explains what makes oxygen enter the stove to make it burn and gives the basics of why it's all about the chimney, not the stove. Damper setting controls the chimney, in turn affecting the stove. Just like the throttle controls the engine that affects the speed of the vehicle. So damper setting and operation depends on the chimney size, temperature, high and low air pressure systems and many other factors including how much heat you need from the stove.
https://www.hearth.com/talk/threads/new-fisher-owner.137880/

 

[Alex C]

I have a damper on my old mill wood stove. I run it full closed all the time once my firebox gets up to about 700. If I don't, I go through wood way too fast. I have a straight 15' chimney with no bends and a top exit flue collar, so I have pretty excessive draft.

 

[coaly]

So tonight while playing around with it in frustration I closed the pipe damper all the way and turned the thermostatic draft up to 3/4 ( I normally run the pipe damper 1/2 and the thermo at 1/2 to get exterior single wall pipe temps of around 450 to 550) closing the damper got my stove too temp up to 700 while maintaining about 450 on the pipe.

It was also much colder than usual making your chimney much stronger. You probably already had inner flue temp hot enough, and closing the damper held the heat in the stove, and the large temperature differential was enough to force air into the stove to keep it going. Terminology used is usually "the draft was strong enough to pull the air in", but in actuality it is air pressure pushing air in. (not all 20 year veteran burners know that) Warmer outdoor temperature or a cooler flue will slow the stove, so you may not be able to replicate that operation easily. That was the right circumstances to make it work, and now you know the capability of the stove with proper draft and flue temp. You can't always create optimum conditions. Just like an engine will put out different horsepower at different temperature and elevation. (again air pressure) Insulated flues or liners get you closer to that optimum condition making the stove more efficient.

 

[coaly]

I have a damper on my old mill wood stove. I run it full closed all the time once my firebox gets up to about 700. If I don't, I go through wood way too fast. I have a straight 15' chimney with no bends and a top exit flue collar, so I have pretty excessive draft.

Good candidate for a baffle if it doesn't have one!

 

[2broke2ride]

So is there a too hot? Other than wasting fuel is there any danger in running the flue hot? As long as the stove itself stays at a reasonable temp. My pipe surface only runs 50 to 100 degrees cooler than my stove top so if I run the pipe in the normal range around 450 my stove is only around 550......... I would like to run the stove hotter if I can.

 

[coaly]

It won't hurt the stove to run hotter. Most manuals state any part of stove or pipe glowing red is a sign of over firing. 600 to 700 is normal. 800* is not unheard of but that's getting near the max.

You mentioned in your original post you're struggling to get enough heat out of it. That's not the stove, it's the chimney. Exactly what do you have? Outlet of stove size, pipe size, flue size and height. This is all critical in the operation of the stove and is what makes it work. An oversize flue larger than the outlet on the stove allows so much heat up and requires much more heat to stay clean. Many times a stove not heating an area is due to so much going up the larger chimney that the stove can't heat the area it's in. With an insulated flue the same size as stove outlet, pipe temp is usually half the stove top temp.

 

[2broke2ride]

Stove has a 6 inch stack and no baffle, gonna try to add a baffle tomorrow and see if it helps........The chimney is concrete with an 8inch square clay liner (7"x7" inside) it's 20ft tall and an interior chimney.
I plan to line with stainless over the summer if the budget allows and maybe replace this old stove with an add on hot air furnace.
I know that I'm losing a lot of heat up the chimney just because of the amount of wood I go through for the amount of heat I get out of it......... About two rounded wheelbarrow loads in 24 hours
Btw, I don't know if I mentioned, this is my first year heating with wood on my own although I grew up with it in my parents house my entire childhood plus my father in law who have me this stove has heated with wood for 40 years.

 

[coaly]

Yep, a liner and baffle would help a lot. Shouldn't need to dampen it off much with a baffle and let it get hot. That's a lot of wood.
A baffled Papa Bear with 7 X 7 masonry chimney uses a rounded wheelbarrow over a 24 hour period in my neighbors and he's heating an unfinished basement and upstairs, about 2800 sf total. He runs the damper about half to 3/4 shut and way hot. No thermometer, but he's had the pipe at damper glow bad enough to see the damper through the pipe! Never had the stove glow, but hotter than I'd run it.

 

[2broke2ride]

Yikes......... I've seen the transparent pipe before, not something I wanna see again

 

[2broke2ride]

I'm shutting her down tomorrow to clean the chimney and install the baffle, also gonna replace the door gasket while I'm at it.

 

[2broke2ride]

Chimney cleaned, had about a coffee can full of dry crumbly stuff after 3 weeks of 24/7 burning......... Think I'll let it go another week next time just don't want to have a repeat of the dec 23 chimney fire. Baffle is installed.......... What should I expect to see different with the baffle? I also found that my flue temp gauge is very inaccurate........... I checked it with a raytec infrared thermometer that I borrowed from work and it seems to be a good 100-150degrees off. The temp gauge reads high. Anyone know where I can get a cheap but accurate temp gauge or infrared thermometer?

 

[bholler]

How did you install the baffle? And box stores usually have pretty cheap ir thermometers

 

[2broke2ride]

I drilled holes through the sides and put in bolts protruding into the firebox and set the plate on it......... The plate sits 4&1/2 inches below the flue outlet and extends 12 inches forward from the back wall, it is 18 inches wide so the 4&1/2 inch space should net the same volume as the 6 inch pipe.

 

[ttamoneypit]

just found this conversation

question did you buy or make your own baffle? I have a shenandoah also and it works ok but I think it could use a baffle

 

[Alex C]

When I bought the stove it was in. It looks factory but some handy welder could have installed it. I do believe it makes a world of difference

 

[ttamoneypit]

could you post some pictures of it ?