Over the last 20 years, there has been a tremendous increase in the types of controls available for hydronic heating systems. They range from simple bimetal thermostats to sophisticated microprocessor-based system management controllers. Control actions range from basic on/off switch action to fully modulating devices operated by PID control algorithms.
PM Engineer surveyed 1,000 randomly selected readers regarding their preferences in controls and control methods for hydronic heating. The survey consisted of 12 questions and had a response rate of 14%.