LME21.350C2 Siemens Burner Control

Overview

The Siemens LME21.350C2 is a microprocessor-based burner control designed for the startup and supervision of 1- or 2-stage gas or gas/oil burners. Engineered for intermittent operation, this controller is suitable for small to medium-capacity burners with or without fan-assisted combustion. It serves as a reliable flame safeguard, ensuring safe ignition, flame proving, and controlled shutdown in commercial and industrial combustion systems.

Features

• Digital signal handling ensures an accurate and repeatable control sequence
• Multicolor LED signal lamp provides clear indication of operational status and detailed fault messages
• Integrated undervoltage detection protects the system by shutting down under unsafe power conditions
• Air pressure supervision includes a functional check of the air pressure switch during start-up and operation
• Electrical remote reset facility allows for convenient system management from a distance
• Designed for a service life of approximately 250,000 start-up cycles or 10 years of normal usage
• Controlled intermittent operation triggers a mandatory safety restart after 24 hours of continuous running

Specifications

• Model: LME21.350C2
• Supply Voltage: AC 230 V (50/60 Hz)
• Power Consumption: 12 VA
• Prepurge Time (t1): 30 seconds
• Safety Time (TSA): 5 seconds
• Waiting Time (tw): 2.5 seconds
• Preignition Time (t3): 4 seconds
• Protection Rating: IP40
• Operating Temperature: -20 C to +60 C
• Weight: Approximately 160g
• Flame Supervision: Ionization probe or QRA flame detector with AGQ3 ancillary unit

Applications

• Supervision of single-stage or two-stage gas burners in commercial heating systems
• Forced draft burner management for gaseous and liquid fuels according to EN 676 and EN 230
• Direct replacement for legacy Siemens LGB21 and LMG21 series burner controls
• Use in HVAC and boiler systems where intermittent operation is required
• Integration by OEMs into industrial combustion programmers and burner trains