The control system is basically a way to control the burn speed of the wood, to keep the water temperature in the correct temperature range. The speed of the burn is directly related to how much air is intorduced to the boiler, and since we have a secondary burn area, we can slowly burn the wood, and still get an efficient burn.
Before I did this, I thought this may be a difficult stage of the proccess, but it is really very easy. There are three componens you will need though.
1- A 110v Elecric blower (I used the Dayton Blower 1TDP7, about $70 found here).
Once you have all the parts, it is easy to setup. Just connect your blower to the inlet of your air injection. I split this off with valves to control the ammount of air to the primary and secondar burn. And then connect your solenoid with the shutoff valve. They also sell a kit with all this together, but there is no need to pay extra for for the kit when this works just fine.
This is inside my shed, and a little hard to see, but the solenoid is connected to the valve using some wire, and this has worked just fine.
Once we have the blower and valve setup, we use the controller to turn it on and off, again this may seem complicated, but it is not. You simply put the thermometer from the controller into the drywell in the boiler, and wire the blower and solenoide to the output of the controller. The controller has a few settings, as it can be used for a heating system or a cooling system. Just set it to heating, the max temperature you want your water, and the change (I set mine to max at 180 deg with a change of 30 deg). This means it will heat up till the water hits 180 deg, then it will shut off until the water cools down to 150 deg. I have noticed that even after the blower shuts off, the water temperature keeps going up because of all the heat that is built up in the hot coals and firebricks, so you won't want to have it much over 180.