Siemens Electromechanical burner control LAL2.25

This electromechanical control box starts and supervises multi-stage or modulating forced-draft oil burners with intermittent operation and manual reset lockout. It applies AC supply voltage to the fan motor after a 2.5 s delay, performs a 22.5 s pre-purge, then energizes the ignition transformer for 15 s. The safety time is 5 s; the intervals between voltage applications and between voltage switchings are 7.5 s each, and post-purge lasts 15 s. The complete start-up sequence takes 47 s, with pre-ignition time 2.5 s.

When selecting a replacement control box of this type, match the exact series and type designation, supply voltage, required safety time, pre-purge time, and flame-detection method of the burner. Verify the voltage rating and the base or plug pattern to ensure physical fit; controls within one series are not interchangeable if the safety-time setting differs. Some burners are fitted with electronic control boards instead; those boards are matched to the boiler model and are not field-interchangeable with a traditional control box. Use the part number on the existing control as the only certain reference if the burner documentation is unavailable.