Seconadary Air Question

[Michael Sean]

Hey everybody, finally decided to join the site after being just a reader for over a year and I have a question that I can't seem to find the answer too.

So after alot of reading and research on this site, I've decided to go with a englander Madison stove (the smaller one). From what I've learned about these new EPA stoves, the only air that is controlled into the firebox is the primary air. The secondary air and dog house air are unrestricted.

I understand the engineers do this to allow for complete combustion of the gasses coming off the wood and to meet EPA regulations.

With that being said, if one was to figure out how to control/regulate the secondary air coming into the stove, would that increase burn times, while still burning clean and efficient?

I'm still new to EPA stoves and haven't been burning wood but a couple of years. I've pretty much learned everything I know from just reading on this site so any help would be great.

 

[BrotherBart]

I control the secondary air on my Englander 30-NC by blocking off a percentage of the secondary air inlet with a magnet. With my 30 foot chimney it was just pulling secondary air too hard. I blocked the percentage of how much my chimney is over the 15-16 foot chimney they design it for the EPA testing. Works a treat. I didn't know I bumped the magnet off cleaning the fireplace one day but did about ten minutes after I lit off the stove and it took off.

The stove burns clean without smoke coming out of the pipe when it gets up around 500 stove top.

 

[Michael Sean]

Thanks for replying so quick brother Bart, but but I'm not really concerned about a overdraft problem.

My question is more on the side of if you can can control the secondary air, could you have more control over burn times, stove temp etc, once the stove is up to the "clean burn" operating range?

 

[bholler]

There are many stoves infact most that control the air to the doghouse. But not to the tubes or airwash. Like bb said if you have to much draft you can limit that air. Otherwise let it alone and let it work as designed. A stack damper will also work

 

[Squirrely]

I control the secondary air on my Englander 30-NC by blocking off a percentage of the secondary air inlet with a magnet. With my 30 foot chimney it was just pulling secondary air too hard. I blocked the percentage of how much my chimney is over the 15-16 foot chimney they design it for the EPA testing. Works a treat. I didn't know I bumped the magnet off cleaning the fireplace one day but did about ten minutes after I lit off the stove and it took off.

The stove burns clean without smoke coming out of the pipe when it gets up around 500 stove top.

Thanks for the clever idea, Bart!

I have a tiny 4.5 kw stove connected to a straight 24 foot high 6 inch flue, so I was going to make a steel slider from some rolled flat stock that's long enough to access from the side. The stove already has two air controls, above and below the firebox. A magnet will make for easy testing to find out how well it would work first, to decide whether or not to install a third control.

Greg

 

[begreen]

Thanks for replying so quick brother Bart, but but I'm not really concerned about a overdraft problem.

My question is more on the side of if you can can control the secondary air, could you have more control over burn times, stove temp etc, once the stove is up to the "clean burn" operating range?

That is the theory behind some PE and Enviro stove designs that have a linked secondary air control.

 

[EatenByLimestone]

Thanks for replying so quick brother Bart, but but I'm not really concerned about a overdraft problem.

My question is more on the side of if you can can control the secondary air, could you have more control over burn times, stove temp etc, once the stove is up to the "clean burn" operating range?

Controlling the draft controls the secondary air. Draft creates negative pressure inside the stove. It pulls air in through the secondaries. Cutting air off to them will make the stove run dirtier.

 

[begreen]

Cutting air off to them will make the stove run dirtier.

Cutting the secondaries off during the full bloom of outgassing from a fresh load of wood will make the stove run dirtier. Cutting them off after the outgassing stage will not, but it will slow down the the burn of the remaining charcoal. In the future we will see more automated controls that do this precisely. There will be a burn lab in Wash. DC (Nov. 2018) where new technologies compete for automating the air control. It will be interesting to see how many regulate the secondary air.

 

[begreen]

FYI, the mfire Catalyst regulates the secondary air automatically for a clean fire throughout the burn cycle.
https://mffire.com/clean-wood-burning-stove-swirl/

 

[Michael Sean]

FYI, the mfire Catalyst regulates the secondary air automatically for a clean fire throughout the burn cycle.
https://mffire.com/clean-wood-burning-stove-swirl/

Begreen this was more on the line of what I was trying to ask with my question.

It's neat how they get their secondary air to mix in the firebox like that. But on the hand of the stove controlling secondary air, do you think they use an electronic monitoring system that allows more or less air in depending on what stage the fire is in?

 

[Michael Sean]

Well I found the answer to my own question after reading more into the stove. The price tag on that thing though

To me it seems like you could just use a bi-metallic thermostat that would in therory do the same thing once calibrated for maximum efficiency. As the stove heats up, it would allow more secondary air into the stove and as the stove cooled down it would decrease the amount of secondary air to allow the coaling stage to last longer. Thus giving you a longer burn time per load. I might be way off track, just ideas floating around.

 

[begreen]

Bimetallics were used in some early models and still are in VC stoves, but the most modern from Hwam, Rika and Quadrafire (Adventure) use sensors (temp and/or oxygen) to determine the stage of combustion coupled with servo driven air controls.

 

[Hiram Maxim]

I control the secondary air on my Englander 30-NC by blocking off a percentage of the secondary air inlet with a magnet. With my 30 foot chimney it was just pulling secondary air too hard. I blocked the percentage of how much my chimney is over the 15-16 foot chimney they design it for the EPA testing. Works a treat. I didn't know I bumped the magnet off cleaning the fireplace one day but did about ten minutes after I lit off the stove and it took off.

The stove burns clean without smoke coming out of the pipe when it gets up around 500 stove top.

Sure it wasn't all the tropical air?