Markel Products Co. 63818003 Thermostat Knob

The Markel Products Co. 63818003 Thermostat Knob is a manual control component that is used to control the temperature settings on thermostat assemblies. It operates by clamping onto the thermostat control shaft, the rotation of which varies the internal setting position to enable the thermostat mechanism to control heating levels when operating in electric heaters and room heating HVAC systems. The knob is placed at the front of the thermostat housing where it joins the control shaft and gives it a grip surface to adjust. The thermostat setting can be controlled by rotation, which will make the temperature control system react to the set point and provide stable equipment operation.