Product overview
Details that help confirm the fit.
The Siemens LME22 is a microprocessor-based burner control box designed for the automatic start-up, operating supervision and safety shutdown of forced-draught gas burners.
Depending on the complete model reference and burner configuration, the controller can be used with single-stage or two-stage gas burners operating in intermittent mode. It manages the burner’s programmed sequence and supervises components such as the combustion-air fan, ignition transformer, gas valves, air-pressure switch and flame-detection system.
Gas-flame supervision can be performed using an ionisation probe or a compatible Siemens QRA ultraviolet flame detector with the required AGQ3 ancillary unit. A compatible QRC1 detector may be used for approved blue-flame applications. The detector must match the controller version, burner construction and approved wiring diagram.
During start-up, the controller checks the required safety conditions, starts the burner fan and supervises the air-pressure switch. After the programmed prepurge period, the controller energises the ignition system and gas valves according to the selected operating sequence.
If a flame is not established within the permitted safety time, the airflow condition is incorrect or an unsafe operating condition is detected, the controller shuts down the burner and enters safety lockout.
Digital signal processing provides an accurate and repeatable control sequence. The controller also incorporates undervoltage detection, electrical remote reset and limitation of repeated burner restart attempts.
A multicolour LED provides operating-status and fault information. Diagnostic flash codes allow qualified service personnel to identify the stage of the operating sequence at which the burner entered lockout.
The LME22 provides controlled intermittent operation by shutting down and restarting the burner after a maximum of 24 hours of continuous operation. This allows the programmed start-up safety checks to be repeated.
The LME family uses the same housing dimensions as the Siemens LGB and LMG burner-control families. Physical fit does not confirm electrical compatibility, so the terminal arrangement, operating sequence, safety timings and flame detector must be verified before replacement.
Typical applications include forced-draught gas burners, commercial boilers, steam boilers, hot-water boilers, industrial ovens, furnaces, hot-air generators and process-heating systems.
Installation, wiring, commissioning, flame-detector selection and lockout diagnosis must be performed by qualified burner-service personnel. The controller must not be opened, altered, bypassed or repaired.
Model, voltage, rotation, pressure range and mounting can vary. Final compatibility is confirmed against the nameplate or existing component.
