My friend, Dave, at McClary Hill Farm, in Epsom, NH hired me to assist him with the installation of his newly-purchased Blue Forge wood-fired boiler and heat distribution system. This is a forced hot water system that doubles as a charcoal production unit, with the unburned gases eventually being saved for fuel to be burned in some of his farm equipment. The charcoal will then be mixed in with compost and earth in a process called, Terra Preta. Dave wrote a grant proposal himself and was successful in receiving a $30,000 matching grant from the State of NH (I hope I have that right). In fact, Dave did much great work himself including, fabricating and welding the charcoal production box onto the side of the boiler, running insulated PEX tubing beneath ground to each building being served by the central heating system, impressively constructing the 10, 150′ foot, 3/4″ copper coils and the 3000-plus gallon storage tank that they will transfer heat from the wood-fired boiler into, and doing a lot of the copper piping that formed the heat distribution piping and potable water in the greenhouse. My job was to design/build the piping and control arrangement so hot water can be properly directed from the boiler into the storage tank and to all space heating zones and indirect-fired water heaters.