Turning Hand Fired Into "Auto" Stove

Ruh-OOOOOOO--he's thinkin again. Mornin HB

haha mornin, always thinking!idk what I am going to do this summer when this thing is off, lol truck pulls I guess

hotblast1357 wrote:now comes time for fabricating the door to mount to a 1/1/2 pipe, and find a 110 volt thermostat to run the blower, I am also thinking, hooking some type of safety (snap disk??) to the furnace or duct work, so that if for some reason it does get hot, the plenum fan will come on, but as usual trying to keep cost down like everyone else

I run my blowers with a thermal snap disc mounted to the top of the furnace's air jacket between the two 8 inch warm air pipes. During a low burn in mild weather, this disc opens (turns the blowers off) at 105 degrees. Then the furnace will accumulate some heat and the disc will close (turns the blowers on) at 115 degrees. This works out great since it saves me some electric cost when the blowers don't need to be running full time. Sometimes during extremely low burns, they hardly run at all, like maybe 15 minutes total per hour.

During colder weather, the top of the furnace jacket stays over 115 degrees which makes the blowers run full time. Which is what I want to keep steady temperature in my living area.

I would advise an independent system similar to this so that your furnace can shed heat when it needs to instead of at the call of a thermostat. Just have the bi metallic thing control your burn rate for more or less heat and let a snap disc control your blowers.

This is how a gas or propane forced air furnace works. The thermostat in the living area calls the burner to ignite, the burner heats a thermo disc which kicks the blower on. Then once the thermostat in the living area is satisfied, the burner shuts off and the blowers continue to run until the furnace cools down and the thermo disc shuts the blower off..

But with my blower running all the time, it will keep the bi metallic cool all the time which will keep my stove hot all the time, which is not what I want, that is what is happening now lol I have to leave it set open enough to keep the house warm when the sun goes down, but during the day its running so hot that my house gets to 80, I work evenings so I'm not there at 3-4 o clock to turn my manual air open more

So the blower is regulating the bi metallic thermostat?

in a sense yes, I was originally going to buy a electronic actuator to move the air supply flap, controlled by a thermostat, but that is to much money and too "complex" I like the KISS theory, so what I would like to happen is, I set my manual air spin control to a turn and a half, which will keep my stove at 250-275, which I found will give me a nice idle, I will unhook the plenum fan from the thermo disk that is orginally on the unit, and control that by a thermostat in the living room, when the thermostat calls for heat, the plenum fan will kick on, which will be blowing cooler air by the outside of my firebox cooling off the bi metallic actuator, becuase that is mounted on the back in the sheet metal, inside the hot air jacket, which will pull up on the flap that I am going to make, which will let a "pre determined" amount of air in, to bring the stove temp up to around 350-375, which is enough to heat my house on the coldest day or night, then once the thermostat is satisfied, the plenum blower will shut off, which will heat the bi metallic actuator up so that it drop the flap shutting the extra air supply off, turning the stove back to an idle

I understand. The only thing that bothers me is that your thermostat will be controlling the convection (plenum) blower. What happens if there isn't a call for heat for a long time? aren't you afraid the furnace won't be able to shed its heat? maybe it will gravity feed some..

Where exactly will the "flap" for combustion air be located? Air you going to make a new hole in the firebox to allow air into the ash pan area? Don't forget, the area between the firebox and the air jacket gets pressurized by the convection blower. If your new opening is in there, pressurized air will feed the fire and have detrimental consequences.. If your bi metallic is between the fire box wall and air jacket, how do you plan to work around this?? The only part of the stove that isn't shrouded by the air jacket is the front, right? I'm trying to picture the logistics of everything. Just trying to help

hotblast1357 wrote: leave it set open enough to keep the house warm when the sun goes down, but during the day its running so hot that my house gets to 80, I work evenings so I'm not there at 3-4 o clock to turn my manual air open more

No one is home that could tweak the primary combustion air? I showed my wife how to..

Thermostats, blowers, electronic actuators...seems to me you have given up the biggest benefits of hand firing, which is a minimum of components and no power required. If you don't have any desire to burn wood, I'd start thinking about a stoker.

Hi Rob, he's got a unit like mine which requires power for the convection blowers. His desire is to get it to regulate heat output automatically.

rob, I would think about it but I just bought it 3 months ago lol so its going to run for a while before I buy something else, lightning, if you look in the pictures I posted, I am going to use the port that they use for the draft inducer fan, which allows air in through the ash area, I do not want to cut into my firebox, so I am going to use the hole already there, it is on the outside of the tin, not in the air jacket, I agree with the heat not being able to be shed, but in the pics I posted a sheet that I took data for an hour, and if you notice that heat temps actually went down after a hour without the plenum running, now I only did this for a hour, I do not know what 4 hours would be, but I would assume that if they slight go up in 20 minutes, then drop for the next 40, I would assume there not going to go back up on there own, and no by the time the wife gets home its already cooled off in the house, and during the night it is the same situation, as far as the mounting, I have a picture posted earlier of it mounted already and it works there, I am using the already existing hole in the sheet metal for the thermo disk, I am going to just make a new hole on the other side so I can keep the thermo disk there

the red circle is where I temp installed it in a hole already in my tin, then blue is where I want to drill a hole and mount it, the next is a illustration of the setup, hard to do with a mouse lol hope this helps

lightnng at idle my stove temp is only 250-275, which I don't think is hot enough to hurt anything, I could be wrong

Oh ok.. I was under the impression you were considering a hole in the fire box underneath the warm air jacket. Hmmm. So how is the mechanism going to turn on the blower? Air in the jacket will get hot since its not moving and keep the flap closed, won't it? Or will it open when its hot?

the thermostat is going to turn on the blower, when air in the jacket is not moving, it will get hot, shutting the flap, then when the thermostat calls for heat, blower will come one, cooling the air jacket, opening the flap

Alright... so... the only situation that concerns me now is this.. when the thermostat turns off the blower, the flap will close. The furnace won't be so fast to respond. It will stay hot for a while before the reduction in combustion air makes the fire cool down..