Siemens Burner control unit LMO64.301C2

This burner control unit is a microprocessor-based control box for forced draught oil burners. It controls startup and safety sequencing for 1- or 2-stage burners with intermittent operation. It monitors the flame using QRB photoresistive or QRC blue flame detectors. Features include undervoltage detection, a shunt contact for oil preheater with time monitoring, and a restart attempt limit. The unit has load control relays, an electronic flame signal amplifier, and a multi-color LED for status and fault indication. Its removable plastic housing snaps into a base, and it offers an optical interface (OCI400) and remote reset signal (AGK20).

Burner controls of this kind are chosen for replacement by matching the exact series and type designation of the installed unit, along with its supply voltage, safety and pre-purge times, and flame detection method (ionisation, UV or IR). The base or plug pattern must be identical; controls from different series, even within the same brand, are generally not interchangeable because mismatched safety times can be hazardous. Before ordering, verify that the wiring for the flame detector, valve, transformer, and fan corresponds to the replacement, and confirm that the control supports the same fuel type and number of burner stages.