On a boiler, the damper is an adjustable iron plate or shutter that's built into the boiler flue as a tool to help regulate the flow of air through it. The damper is comprised of blades or louvers to regulate the air flow. Usually, dampers include an electro-mechanical device that opens and closes the damper to prevent heat from escaping the flue during the burner's rest period. That control device is the damper motor.

Types Of Damper Motors

Damper motors can vary based on wattage, voltage, general size and return method, such as a spring return. A Honeywell ML4115B1008 two-position actuator comes with a clockwise spring-return and a shaft of three-eighth inches to one-half inch, offering 30 lbs. per inch of torque and a peak power consumption of .18 amps for this 120-volt device. For something comparable, Dayton's 2LRZ3 direct coupled actuator also comes with a spring return and 120-volt power, offering the same torque and peak power consumption. The only differences in their specifications are the ambient temperature range–specified as 0 to 130 degrees for the Honeywell model and 32 to 122 degrees for the Dayton model; and the electrical connections, noted as an integral junction box with three conduit openings for the Honeywell model and 18-gauge, two-color coded 3-foot leads for the Dayton model. A Siemens GCA121.1P two-position actuator draws 24 volts and yields a torque of 142 lbs. per inch, evidence of variations, even within similar ranges.

Replacing A Damper Motor

The replacement of a damper motor is quite easy, requiring only the removal of a setscrew that holds the motor to the damper.

Who Makes Damper Motors?

While by no means an exhaustive list, manufacturers of damper motors include:

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