Overview Similar Products –> Product Description 19-FS2-110 Thermal Switch Part Opening Temperature- 90 Degrees F Closing Temperature – 110 degrees F. (3/4 inch disk shape) 25 amp This can be added to any of the furnace units that do not come with this switch. Simply place it in line with the power, mount the switch on the furnace housing / jacket so that will allow the fan to come on as the fireplace gets hotter and will also turn it off as it cools down. Do not mount directly on fire box. Cross ref: 80P20038R, COR110F, PP3101 Product Videos Custom Field Product Reviews