Belimo S1A Switch

The Belimo S1A Auxiliary Switch provides reliable end-stop signaling and interface capability for an extensive range of non-spring return actuators, including the LM, NM, AM, and GM series. This single-pole double-throw (SPDT) switch is designed to replace the legacy AM-661 model, offering a seamless field-addition for contractors managing damper automation or HVAC control systems. Engineered for precision, the switching point is fully adjustable across the entire rotation range of 0 to 100%, allowing for custom feedback settings in complex BMS integrations. The unit features cULus listed construction and a rugged housing that mounts directly to the actuator, ensuring consistent operation in demanding commercial mechanical rooms. By integrating this add-on auxiliary switch, technicians can effectively trigger secondary equipment or provide status verification to the master controller without requiring additional external relays or complex wiring configurations.

• Universal Compatibility: Direct-mount design works with Belimo LM, NM, AM, and GM actuators, streamlining truck stock requirements.
• Precise Synchronization: Features an adjustable switching point to ensure accurate feedback for position monitoring.
• Simplified Replacement: Serves as the direct technical successor to the AM-661, maintaining consistent footprint and wiring logic.
• Industrial Durability: Built to withstand the vibrating environments of HVAC air handling units and ductwork.
• Easy Commissioning: Minimal tools required for installation and calibration, reducing labor time during system retrofits.

Is the switching point fixed or adjustable in the field?
The switching point is fully adjustable by the technician. You can set the SPDT contact to trip at any specific degree of rotation to match the requirements of your damper sequence of operations.

Can this switch be used with spring-return actuators like the AF or NF series?
No, the S1A is specifically designed for non-spring return actuators. For spring-return models, you would typically utilize the S2A or integrated internal switches depending on the specific actuator series.

How do I wire the S1A for status feedback?
The unit utilizes standard SPDT wiring. You will track the common, normally open, and normally closed leads to provide the necessary signal to your DDC controller or auxiliary relay.

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.