Boiler install diagrams
First a little bit of information about heating a large structure like a big old house. Corn boilers (or any other solid fuel heating device) do not Recover as fast as natural gas boilers. So, from cold, the boiler warm up time from cold is not as quick with corn.
This causes a situation where, though the boiler is hot (180 degrees), the house radiators might be cold because the thermostat in the house is not calling for heat. When the house temperature does get low enough to trip the thermostat, the water pumps kick in. When this happens, the cold water returning from the radiator returns suddenly drop the boiler temperatures. It can drop quite low, below 80 degrees, quite quickly. This hundred plus degree drop can cause boiler damage, warping the heavy steel of the boiler water tank or heat exchange tubes.
A user in Chippewa Falls (http://forum.iburncorn.com/profile.php?mode=viewprofile&u=56 jasand) setup the following boiler layout. It utilizes a buffer tank, to increase the total thermal value of the hot water on a primary loop. It then heats the house off a secondary loop. This has the advantage both of having more thermal mass in a case where the house is calling for heat, but also, with an aqua stat on the secondary loop, pumps can be shut off before the boiler temperature drops critically low.