Automatic Dampers- Where's the challenge?

turbojoe said:

Sounds like everything a Smart Stove Controller can do.

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TurboJoe, Is this what you are referring to?
http://inveninc.com/faq/

Back to original question of why these aren't used more, its a tidbit of history from 1987 from the EPA. A manufacturer wanted to add a bi-metalic coil, but not test the stove with it. The EPA said thanks, but no thanks. You have to test the stove as its built for the consumer to use:

"The combustion air supply on a stove is controlled by a bimetallic thermostat. Should the bimetallic thermostat be overridden during certification tests to achieve the maximum heat output?"

"The stove should be tested in the same way that it is intended to be installed and used in a home, except in cases that are clearly identified in the regulation or in special cases where it is not reasonable for the consumer to operate the appliance based on instructions to the operator. Therefore, the bimetallic thermostat should be used to adjust the combustion air supply and should not be overridden during the high burn rate test. In instances where the combustion air supply is controlled by a remote thermostat, the manufacturer should get special instruction from EPA for testing the appliance before conducting the certification tests."

Cheeks said:

TurboJoe, Is this what you are referring to?
http://inveninc.com/faq/

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That's it, Mine should be here this week, stay tuned Dan has incorporated alot of nice features into his controller.

valuman said:

Keeping in mind that today marks the end of only the third week of me burning my stove, it occurs to me that having a cat stove complicates the automatic damper option. I'm seeing higher stove top temps when I close the damper down on a hot, loaded firebox. So without having a microchip to regulate based upon multiple parameters it seems that when the temp drops the damper opening might cause it to drop further, causing the damper to open wider. What am I missing?

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It's all in where you measure. You ideally want to monitor three temperatures, for operation of a catalytic stove:

1. Stovetop, used to ensure you're not overfiring / damaging the stove, and to control heat output setting.
2. Stovepipe, used to determine when to engage catalyst.
3. Catalytic probe, used to ensure you're getting light off, and to ensure you're not overfiring the catalyst.

That's actually just for dumb manual operation. A self-learning controller could be set up to throttle according desired burn time / output profiles, monitoring the ratio of catalytic to stovetop temps, or for minimizing flue pipe temp for a given stovetop temp range.

I just implemented v1 of automating my draft control on my Buck 81 insert. Hopefully the pics show up below. I used a 12v linear actuator controlled by an Arduino microcomputer with a relay shield. Pretty easy coding, as I mimicked a stepped time delay similar to how I would manually (and slowly over 20 min or so) close the draft control. It works great! I have a button setup that initiates the sequences (basically starts a timer with delays built in to move the actuator). It's almost humorous to load wood, hit a button, and sit on the sofa and hear a electric motor turning on/of every 7 minutes or so. Mostly I did it because of the middle of the night wood loads. No more sitting around half asleep babysitting the control. I'm working on v2 now, which incorporates a push/pull cable. The cable will be attached to a fabricated bracket on the stove end, and the other end (about 4' away) will go to some sort of a case that will house the actuator, computer, power supplies and buttons. It will also be a much cleaner setup. It's ugly now but it works.

buckfan said:

I just implemented v1 of automating my draft control on my Buck 81 insert. Hopefully the pics show up below. I used a 12v linear actuator controlled by an Arduino microcomputer with a relay shield. Pretty easy coding, as I mimicked a stepped time delay similar to how I would manually (and slowly over 20 min or so) close the draft control. It works great! I have a button setup that initiates the sequences (basically starts a timer with delays built in to move the actuator). It's almost humorous to load wood, hit a button, and sit on the sofa and hear a electric motor turning on/of every 7 minutes or so. Mostly I did it because of the middle of the night wood loads. No more sitting around half asleep babysitting the control. I'm working on v2 now, which incorporates a push/pull cable. The cable will be attached to a fabricated bracket on the stove end, and the other end (about 4' away) will go to some sort of a case that will house the actuator, computer, power supplies and buttons.

Click to expand...

Good stuff, keep us in the loop on your progress.

Cool, but... Yikes! At least get those components moved from the breadboard to some perfboard! I don't have to tell you how easily a wire pops out of those breadboards.