Siemens Building Technology ASK791.165 Fusible Link

The Siemens ASK791.165 is a precision-engineered 165F electrical fusible link designed for integration with UL-listed fire and smoke control damper actuators. Built specifically for the OpenAir GJD series, this heat-responsive device serves as a critical fail-safe within commercial HVAC ventilation systems. When ambient duct temperatures exceed the 165°F (74°C) threshold, the sensor interrupts power to the actuator, allowing the internal spring return mechanism to drive the damper to its safety position immediately. This rapid thermal response is essential for maintaining life safety protocols and preventing the spread of smoke and fire through air handling units.

As a field-replaceable component, the ASK791.165 ensures that fire dampers remain compliant with local building codes and NFPA standards without requiring a full actuator teardown. Its robust, gray housing and high-visibility wiring make it a standard choice for technicians performing maintenance on Siemens building technology systems. For contractors managing large-scale HVAC life safety installations, these links provide the necessary reliability for demanding smoke control applications where precise temperature sensing and power interruption are non-negotiable.

• Thermal Response Accuracy: Precisely calibrated to trigger at 165°F (74°C) for reliable fire boundary protection.
• Actuator Compatibility: Engineered for seamless interface with Siemens OpenAir GJD series damper actuators.
• Fail-Safe Operation: Automatically cuts power to trigger the spring return, ensuring dampers close even during power loss.
• Durable Construction: High-quality materials designed to withstand the harsh environments of industrial ventilation ductwork.
• Code Compliance: Supports UL listings for smoke control systems, helping facilities meet stringent fire safety regulations.

Is the ASK791.165 resettable after it has been tripped?
No, like standard fusible links, this is a "one-and-done" safety device. Once the 165°F threshold is reached and the link melts or breaks the circuit, the unit must be replaced to restore the actuator's normal operation.

Can I use this link with non-Siemens actuators?
This component is specifically designed and UL-tested for use with Siemens OpenAir fire and smoke actuators. Using it with third-party hardware may compromise the safety rating and the mechanical spring-return function of the system.

What is the primary indicator that the fusible link requires replacement?
If the actuator remains in its fail-safe (closed) position despite having supply voltage present at the controller, the ASK791.165 may have tripped due to an over-temperature event or circuit failure, requiring a continuity check and replacement.

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.