Welcome to our ‘How-To’ video series!
High Limit / Cutoff Switch: Bypassed / Safety Issue
- Locate the high limit cutoff switch, usually mounted near the thermostat controls or boiler jacket.
- Follow the wires from the cutoff switch to determine the normal circuit path.
- Check for any additional wires that are connected to the cutoff switch terminals that divert the circuit path.
- Examine wiring diagrams for the boiler controls to verify if the altered wiring bypasses the cutoff switch.
- Check boiler temperature and operation to determine if overheating is occurring due to the cutoff bypass.
- Carefully disconnect any jumper wires or wiring not original to the boiler controls that bypass the cutoff switch.
- Restore the original control circuit wiring path through the high limit cutoff switch terminals.
- Allow boiler to fully cool down before attempting to restart.
- Press the cutoff switch reset button once cooled and verify boiler ignites only below the high limit temperature threshold.