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Flame sensor CAD sensor

panther Member Posts: 6
edited May 2017 in THE MAIN WALL
Can the cad sensor ever be bad and keep shooting oil into the burner box instead of shutting down the boiler oil burner


  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Anything is possible, however your primary control would notice if the CAD were shorted initially and should lock out. Older primary controls wouldn't care. You should be able to unhook the yellow (usually) wires and the primary control should simply run and timouut resulting in a lockout.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    HVACNUT Member Posts: 5,861
    We need a better explanation. Raw fuel or is there combustion? Can you post a pic of the burner? What exactly is happening? A bad fuel pump can continue to dump oil into the chamber during the off cycle.
    A bad cad cell eye will usually not read the correct resistance and open the burner circuit. If it failed during a run time reading the correct resistance, it would not recycle due to false flame sense before ignition.