LFS1.11A1 Siemens Flame Detector Relay

Overview

The Siemens LFS1.11A1 is a high-performance, digital flame detector relay designed for the supervision of oil flames in industrial and commercial burner applications. Engineered for continuous operation, this compact device acts as a flame switch that signals the presence of a flame to a programmable logic controller (PLC) or other burner control units like the Siemens LEC1 or LMV5 series. By providing reliable flame monitoring and a potential-free contact closure, it allows for sophisticated combustion safety management within modern HVAC and boiler systems.

Features

• Designed for continuous operation mode for the supervision of oil flames
• Compatible with Siemens RAR9 photocell detectors for high-precision flame sensing
• Integrated BCI communication interface for parameterization and diagnostics
• Multicolor LED signal lamp provides immediate local flame status and diagnostic information
• Analog 0-10 V DC output signal for monitoring flame signal strength via external displays or controllers
• Potential-free signal contacts with double insulation for enhanced safety and flexibility
• Robust and extremely compact design saves valuable control panel space
• Undervoltage and overvoltage detection to ensure safe operation under varying power conditions

Specifications

• Model: LFS1.11A1
• Mains Voltage: AC 120 V (-15% to +10%)
• Mains Frequency: 50/60 Hz (+/- 6%)
• Flame Detector Compatibility: RAR9 (Photocell)
• Safety Integrity Level: SIL3 capable
• Power Consumption: Approximately 3.5 VA
• Protection Rating: IP40
• Operating Temperature: -20 C to +60 C
• Weight: 115 g (approx. 0.25 lbs)
• Expected Life Cycle: 250,000 to 1,000,000 startup cycles depending on load

Applications

• Supervision of oil burners in industrial heating plants (EN 746-2)
• Use in ship burners and marine combustion applications
• Multi-burner plants requiring individual flame supervision with centralized control
• Integration with PLCs where the PLC manages burner sequencing and safety interlocks
• Replacement for legacy Siemens LAE10 (110V) units using an adapter base
• Dual supervision systems requiring multiple detectors for ignition and main flame monitoring