Slant Fin 410-699-000 Aquastat

The Slant Fin 410-699-000 Aquastat is an essential component for technicians managing high-limit or operating control on hydronic boilers and heating systems. This immersion aquastat is designed to precisely regulate water temperature, featuring a Single Pole Single Throw (SPST) internal switch that breaks the circuit on a temperature rise. Rated for a high-temperature range of 180-240F, it serves as a critical safety or operational limit to prevent overheating and ensure stable boiler output. This model is a direct replacement for the Resideo L4080B1253/B and is compatible with a wide array of Slant Fin and industrial boiler configurations.

Built for durability in demanding mechanical rooms, the 410-699-000 provides consistent terminal performance and responsive sensing. The direct immersion design allows for accurate thermal feedback from the heating medium, ensuring that the system shuts Down immediately when the setpoint is reached. Its compact footprint simplifies retrofitting in tight boiler tapings or control cabinets, making it a reliable HVAC replacement part for both residential and commercial hydronic applications.

• Features a high-limit 180-240F temperature range for robust boiler protection and control.
• SPST switching logic provides dependable circuit-breaking on temperature rise for safety compliance.
• Compatible as an OEM replacement for Slant Fin boiler models and various hydronic heating controllers.
• Immersion-style sensing ensures fast, accurate thermal response compared to strap-on alternatives.
• Rugged construction and high-quality terminals withstand continuous high-temperature cycling.

Is the Slant Fin 410-699-000 compatible with older L4080B series controllers?
Yes, this unit serves as the modern industry-standard replacement for the discontinued L4080B1253/B immersion controllers.

What is the difference between SPST and SPDT aquastats in this application?
This SPST aquastat is specifically designed to open the circuit (break) on temperature rise. For applications requiring a circulator to start on temperature rise, an SPDT or "Make" on rise model would be required.

Does this unit include the immersion well?
Standard replacement kits typically use the existing well unless otherwise noted; ensure 1/2 or 3/4 inch NPT compatibility and proper bulb seating for accurate sensing.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.