High Limit 250° Snap Switch # 12147705
There are two of these switches on each stove. One of them is mounted over the convection room blower and the other is mounted above the air intake or above the ash pan area. Both switches are inline with the auger feed wiring and are normally closed (NC) to allow power to flow to the auger motor under normal conditions. If either switch detects a temperature higher than 250°F, power cut when the switch activates and will automatically be reset back to NC operation once the switch detects a temperature drop of 30°F. Unlike most high limit switches used on pellet stoves, this switch does not require a manual reset (pushing a button) and will automatically restore the circuit when the stove cools down.
These switches do not usually fail. Additionally, these switches do not report an error code to the controller either. The most common trigger for an opening high limit is a failing room blower. If the stove is not feeding and you suspect that this switch is not working properly, test the switch for continuity across the contacts at room temperature.
This is a L250-30 made from a bakelite material which is high-heat tolerant. Because it's normally closed, it's most often referred to as a limit switch. At ambient room temperature this switch is normally closed or ON and is ready to power a circuit. The switch will open at 250 degrees to cut power and will return to it's normal state at 220 degrees to restore power automatically. Failure of this switch happens when it stops opening or closing at the designated temperature thresholds.
