Siemens Burner Controllers LFL Series
Siemens Burner Controllers LFL Series (LFL1) are industrial burner control units designed for medium- to high-capacity gas, oil, and dual-fuel forced-draft burners. They support multistage and modulating operation, providing automatic burner startup sequencing, checked air damper control, ignition management, and flame supervision using QRA2/QRA4/QRA10 UV flame detectors or an ionization probe. Suitable for industrial boilers and stationary air-heating systems operating in intermittent mode.
Product Details
Siemens Burner Controllers LFL Series
Siemens Burner Controllers LFL Series
Siemens Burner Controllers LFL Series (LFL1) are automatic burner control units designed for medium- to high-capacity gas, oil, and dual-fuel forced-draft burners.
These controllers support multistage and modulating burner operation, providing automatic startup sequencing, prepurging, ignition control, fuel valve management, air damper positioning, and flame supervision.
The LFL1 Series is designed for intermittent operation, requiring at least one controlled shutdown every 24 hours. Its integrated monitoring functions help support safe and reliable industrial combustion processes.
Key Features
- Suitable for gas, oil, and dual-fuel burners
- Designed for medium- to high-capacity forced-draft burners
- Supports multistage and modulating burner operation
- Automatic burner startup and ignition sequencing
- Flame supervision using QRA2, QRA4, QRA10 UV detectors or an ionization probe
- Checked air damper control with OPEN, CLOSE, and MIN positions
- Air pressure monitoring and flame failure supervision
- Safety lockout under specified fault conditions
- Remote lockout indication and reset capability
- Type-tested and approved in accordance with EN 298
Applications
- Industrial boiler systems
- Oil and gas burner systems
- Dual-fuel burner installations
- Stationary industrial air heaters
- Multistage and modulating combustion systems
Available LFL Series Models
Models listed in Siemens technical documentation include LFL1.122, LFL1.133, LFL1.322, LFL1.333, LFL1.335, LFL1.622, LFL1.635, and LFL1.638.
Prepurge times, ignition safety times, and control sequences vary depending on the model. Model compatibility should be verified before selection.
Product Selection Guidelines
When selecting a Siemens LFL burner controller, consider the fuel type, burner operating mode, flame detection method, supply voltage, and existing controller model number.
Note: Installation, replacement, and commissioning should be performed by qualified personnel in accordance with Siemens technical documentation and applicable safety regulations.
Technical Specifications
Siemens LFL Series Technical Specifications
| Brand | Siemens |
|---|---|
| Series | LFL1 Series |
| Product Type | Burner Control Unit |
| Fuel Type | Gas / Oil / Dual-Fuel |
| Burner Type | Forced Draft Burner, Multistage / Modulating |
| Operating Mode | Intermittent Operation (at least one controlled shutdown every 24 hours) |
| Supply Voltage |
AC 230 V (-15% / +10%) AC 100–110 V, model dependent |
| Supply Frequency | 50–60 Hz ±6% |
| Power Consumption | Approx. 3.5 VA |
| Built-in Fuse | T6.3H250V |
| External Primary Fuse | Max. 10 A (Slow-Blow) |
| Degree of Protection | IP40 when installed, excluding terminal base |
| Safety Class | Class II |
| Weight | Approx. 1,000 g |
| Operating Temperature | -20 to +60 °C |
| Relative Humidity | Below 95% RH |
| Installation Altitude | Max. 2,000 m above sea level |
| Flame Detection |
UV Detector QRA2 / QRA4 / QRA10 Ionization Probe |
| Minimum Ionization Current | 6 µA |
| Minimum UV Detector Current | 70 µA |
| Ionization Detector Cable |
Standard: Max. 80 m Shielded: Max. 140 m |
| UV Detector Cable |
Standard: Max. 100 m Shielded: Max. 200 m |
| Compatible Plug-in Bases | AGM410490550 / AGM14.1 (ordered separately) |
| Applicable Standards | EN 298 / DIN EN 13611 |
Model Comparison
| Model | Series | Prepurge t1 | Safety TSA |
|---|---|---|---|
| LFL1.122 | 02 | 10 s | 2 s |
| LFL1.133 | 02 | 9 s | 3 s |
| LFL1.322 | 02 | 36 s | 2 s |
| LFL1.333 | 02 | 31 s | 3 s |
| LFL1.335 | 01 | 37 s | 2.5 s |
| LFL1.622 | 02 | 65 s | 2 s |
| LFL1.635 | 01 | 66 s | 2.5 s |
| LFL1.638 | 01 | 66 s | 2.5 s |
Note: Prepurge time (t1) and ignition safety time (TSA) vary by model. Reference: Siemens Data Sheet CC1N7451en (21.04.2022).
Dimensions
Documents & Downloads
Frequently Asked Questions
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