Hello Folks Kind of long post here so be warned!
Just wanted to say that this is a really great forum, I've been lurking here for a month or two and now that my stoker is up and running, I thought I would share some Pix of it and the story.
I have been a fairly long time coal user, for the last 24 or so years we have burned coal in a VC Resolute. It was/is a good stove, but it took a lot of hands on tending to keep it burning well. On warm days, It could only be turned down just so much so we would swelter and on really cold days, it just didn't put out quite enough heat.
Being a fairly devout Craigslist reader, I found someone here in NJ selling a Harman Magnum for $500. It was in fairly rough shape, they had it in a basement that was quite damp and there was a lot of rust on this baby. I completely disassembled it, and cleaned all the rust and scale inside and out, and gave it a fresh coat of paint. New gaskets all around, and a new pyro ceram glass for the door and some noxon metal polish to get the brass to shine again and she was back in shape.
I had just gotten about a ton of nut coal in October so I decided to keep burning the Resolute to burn up some of that coal. This gave me about a month and a half to get the Harman ready.
This weekend we swapped out the stoker for the VC and so far so good. Its been a warm weekend here so the stove is idling along in pilot mode, at about 225 to 250 deg, just above the door. The flue pipe is running real cool, easily touchable by hand, the VC never ran quite this cool, but it seems to be drafting well enough, and is putting out quite a bit of heat.
After reading the CoalTrol posts, I decided to build a controller that would control the stoker in a similar fashion. The unit I made has a Crouzet micro Plc that monitors room temperature and compares it to a preset value. It then calculates an error value that controls the on and off times of the stoker. There is a built in LCD on this unit, and on it I display the setpoint, room temp the amount of correction applied and the remaining on or off time of the cycle. It can also be used in a manual mode where the on/off time ratio is set by a dial. Two ceiling fan speed controls were added to allow the combustion air and convection blowers to be run at reduced speed. The temperature sensor is a kit board that uses an IC to send a 0 to 10V room temp signal back to the controller.
Lastly, I noticed that the stoker motor tends to run pretty hot, the previous owner had replaced it at about the 5 year mark, so I added a small fan on the cover that blows directly onto the motor, that did the trick.
I hope to add a hot water coil that will supplement my propane boiler. but that will be a later project.
Thanks for reading my long first post
My Weather Page: http://www.webusers.warwick.net/~u1046951/
This link is broken, either the page no longer exists or there is some other issue like a typo.