my limit switch on my oil furnace does not shut off the burner when it hits the limit.I replaced the limit twice maybe I had a bad one still no luck . While furnace was running I took the thermostat off the wall and the burner keep running still . Can you tell me what to look for next. does the fossil fuel system have anything to do with this?
The high limit being taken off the wall of the fire box it will never over heat. Try removing 1 of the leads to the switch if the furnace keeps running it is not the limit switch. Most of these limits have a manual reset button you need to press if they do overheat. If the furnace keeps going with the limit wire removed you need to have the controls fully checked out as this is a safety hazard.