In February’s Renewable Heating Design column, I described a simple yet sophisticated design for a system that supplies space heating and domestic hot water using a pellet boiler as the primary heat source. The piping and electrical schematics for that system are shown in Figures 1 and 2 below.
Every hydronic system design should include a piping schematic, electrical control schematic, a description of operation and initial settings for all controllers. The following is a description of operation for the system shown in Figures 1 and 2.