5-Second Fix: Light and Blower Not Working?
Remember that most outdoor boilers are equipped with a safety feature called a "High Limit Switch". This safety switch trips when the boiler water temp hits 190 degrees and it cuts power to the blower fan and light.
If your blower fan and light don't have power, all you need to do is press the red reset button on the High Limit Switch!
However, you must wait until the boiler water temp drops. Normally the High Limit Switch cannot be reset until the boiler temp drops below 150 degrees.
This High Limit Switch is located on most boilers in the rear on the back wall near the aquastat. GH model furnaces have the switch located in the front control box behind the metal plate (remove with one screw).
Outdoor boilers equipped with a High Limit Switch WILL NOT FUNCTION without a functioning switch. These High Limit Switches have only a limited number of trips - then they die. We recommend having a spare High Limit Switch on hand in case yours dies and cannot be reset. The High Limit Switch only costs $28.95 and can be purchased by clicking HERE, or call our office at (231) 221-0104 during our normal business hours 9am-8pm EST M-F.