Conventional boiler controls produce one temperature of heating water, a temperature calculated to keep your house warm on the coldest day of the year. (In Boston, the coldest day’s temperature, or design temperature, is between 9 degrees and 0 degrees F.) Each winter, the design temperature is reached for only a few days and sometimes only for a few hours, but the boiler operates with a water temperature to match this outdoor temperature for the entire heating season, a season in New England which stretches from October to April (or May). Weather sensitive or outdoor reset control on your boiler allows the boiler water temperature to modulate with the outdoor temperature.
Every three degree drop in boiler water temperature equals a one percent fuel saving, so using outdoor reset saves substantial money. For example, if it is a 0° F. design day outside, your boiler will produce 180°water. When the temperature warms to 40°, an outdoor reset control will allow your boiler to produce 150° water, a drop of 30° in water temperature or a ten percent fuel saving.
Outdoor reset controls can be added to your system at any time and do not require the system to be drained. Sensors are added externally and the initial cost is for the control and the electrical wiring. We recommend adding reset to almost any existing forced hot water heating system for immediate fuel savings, system comfort, and efficiency.