Automatic Boiler Water Temperature Control

Replacing your manually adjusted, fixed temperature boiler water temperature control with an automatic control is a cost-effective measure which will ensure maximum energy savings.

Manual vs. Automatic Temperature Control

Temperature requirements for heating water vary considerably with outdoor temperature of 0°, the boiler water temperature may need to be 180° to properly heat the building; whereas with an outdoor temperature of 40°, the boiler water temperature may only need to be 120°. A manually-operated control must be adjusted to respond to changes in outdoor temperature. Because of the labor cost, most building owners do not adjust the control more than a few times a year-far less often than is needed to reap the maximum energy savings. An automatic control adjusts itself to varying outside temperatures on a continuous basis, thereby assuring the optimal savings.

Direct Control of the Boiler Water Temperature

The simplest but usually least effective method is to control the boiler water temperature setting. Unfortunately, the lowest temperature possible under this method is 140° (160°-165°) - which is far above the lowest temperature potentially needed, thus reducing savings. (Setting the boiler temperature too low can cause damage to the boiler. Check with your boiler manufacturer for safe temperatures.)

Installation of a Three-Way Mixing Valve

The second and perhaps most effective method is to install a three-way mixing valve controlled by an outside temperature sensor. The valve mixes return water with the hotter boiler water to reach the desired hot water supply temperature. In other words, the outside air temperature resets the hot water supply temperature according to a predetermined, adjustable schedule.

Installation of a Heat Exchanger

Installing a heat exchanger and creating two independent piping loops (one for the boiler and one for the building) also allows hot water reset control without boiler shock. This also requires an additional circulating pump.