Photocells

The photocell “sees” the flame inside the burner and tells the control box that combustion has started. If it sees no flame, the control box shuts off the oil supply and locks out the burner for safety. A dirty or faulty photocell is a common cause of a burner that starts and then stops.

Each photocell matches specific control boxes, so keep the code of the old one (e.g. Siemens QRB, Satronic MZ, Brahma FC). Before replacing it, try cleaning it; that is often enough.