Cad Cell Testing

Have you ever had your waste oil burner trip into lockout as if it’s not burning, when in fact it is? Maybe you have a bad Cad Cell, but how would you know?

EnergyLogic Burner Assembly Detector Cad Cell

EnergyLogic Flame Detector Cad Cell


The Cad Cell on your EnergyLogic Waste Oil Heater or Boiler senses the flame by detecting light in the visible spectrum, and is an important safety-feature of your EnergyLogic Waste Oil Burner. If, for whatever reason, the flame goes out inside your burner, the Cad Cell/ Photo Eye is there to shut down the other systems, including the pump, to prevent excess fuel from being pumped into your burn chamber. Jumping the “F-F” terminals on your control module bypasses this important safety feature, and allows the pump to continue running for priming purposes. So, as always, abide by all manufacturer’s safety recommendations and don’t run your waste oil burner for an extended period with those “F-F” terminals jumped.


The most obvious symptom of a bad Cad Cell/Photo eye would be for your waste oil burner to enter thermal lockout while it is in fact burning. This can be determined by watching through the peep-hole as the machine is starting up, and seeing if a flame is present and THEN the machine resets itself


To troubleshoot the Cad Cell/ Photo eye the first step is to clean the photo-eye with light pressure and a soft cloth. A dirty photo-receptor will effectively hide the flame from the cad cell, tricking the machine into thinkingit’s not actively burning.

If the Photo eye is clean, move forward. With the Burner cord unplugged, and the transformer closed, the photo eye is in the dark. Your resistance across the “F-F” terminals should be very high, in the 30k ohm range, or appearing as an open circuit. With the Cad cell exposed to daylight that resistance should drop to below 1600 ohms. If yours doesn’t, we can ship you one today!

And, as always, don’t hesitate to call 1-800-347-9575 with any questions or concerns, we’re here to help!

(PN 20210110)


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