Siemens LME21.330C2 , Sequence Controller

Product Overview

The Siemens LME21.330C2 is a microprocessor-based burner control unit specifically designed for the startup, supervision, and control of 1-stage or 2-stage gas burners with fan control in intermittent operation. It is engineered to provide high-precision timing and advanced safety monitoring, ensuring compliant operation for burners where a specific safety time ($t_{TSA}$) of 3 seconds and a pre-purge time ($t_1$) of 30 seconds are required.

Technical Specifications

Feature: Technical Data

Product Model: Siemens LME21.330C2

Operating Voltage: AC 220 V – 240 V

Frequency: 50...60 Hz

Pre-purge Time ($t_1$): 30 Seconds

Safety Time ($t_{TSA}$): 3 Seconds

Pre-ignition Time ($t_3$): 2 Seconds

Degree of Protection: IP40

Application: 1 or 2-Stage Gas Burners (Intermittent)

Key Features

Microprocessor Intelligence: High-precision timing sequences that remain stable regardless of voltage fluctuations, managing the complex interaction between the fan, air pressure switch, and fuel valves.
Multicolor LED: Integrated visual status indicator and diagnostic system. It provides clear color-coded signals for different phases (e.g., green for operation, flashing yellow for startup) and fault diagnostics.
Undervoltage Detection: Critical safety feature that triggers a controlled shutdown if power levels drop below the operating threshold, ensuring the burner does not attempt to restart under unsafe electrical conditions.
Flame Supervision: Optimized for use with Ionization Probes or QRA... Flame Detectors (requires AGU2.5... ancillary unit) to ensure reliable flame detection across various industrial gas applications.