Siemens LGB21.550A27 control box

Siemens LGB21.550A27 electromechanical burner automatic controller for pre-purge with low air volume and drive control. Used for start-up and control of one- and two-stage gas or combined gas/oil burners with intermittent operation. Pre-ventilation time: 50 s. Safety time: 5 s. Time before ignition: 2 s.