How to build an Outdoor Wood Boiler Part 2

Wood Boiler Part 2

Remember as we continue this project you are learning from my experience i.e., my mistakes. Let’s continue on with the plumbing required for our outdoor boiler. It seems to be best if you keep the boiler itself within 100 feet of your house, keeping in mind that the normal wind direction in winter is from the southwest heading northeast. This means watch where you put it so the smoke from the boiler isn’t blowing at your house. You will need to run 2 lines from the boiler to the house, 1 being a feed line and the other a return line. Pipe diameter should be at least .750” and if you are at the longer end of the 100 feet 1” diameter would be best. The pipe used for this is a plastic pipe and Pex is the favorite brand to use. These pipes will come from and return to the boiler using a circulation pump. Taco is a commonly used circulation pump; however there are several other manufacturers. This circulating pump, or in some cases pumps, circulates the water from the water jacket of the boiler through the heat exchanger in the plenum of your furnace. I say pump for the reason that if you have a long run an extra pump helps the water to circulate at the rate it need to. You will also want a diverter valve at the furnace that prevents the hot water being circulated from entering the plenum when there isn’t a call for heat by the thermostat. If you don’t use this diverter valve heat will accumulate in the plenum and your safety switch will have the furnace fan engage even if the thermostat isn’t calling for heat. This diverter valve is also controlled by the wood thermostat, being that if it calls for heat then the diverter valve opens and allows the hot water to go through the heat exchanger creating hot air to blow into the building via your heat ducts.