A Firestat duct limit control plays a large role in safeguarding HVAC systems by shutting down equipment in the event of excessive air temperatures. This ensures the prevention of potential hazards such as fire outbreaks. Commonly utilized in environments like apartment complexes and other multi-unit installations, these controls are integral components in specialized HVAC applications and Building Automation Systems (BAS). For additional information or to request OEM pricing, contact us.
Functionality of a High Temperature Duct Limit Control
Firestat duct limit controls are equipped with Duct High Temperature Switches, featuring a helix bimetal element. This bimetal element is designed to detect rapid increases in duct temperature, typically indicative of fire incidents. When the temperature surpasses a pre-set limit, the high temperature limit triggers an SPST switch, interrupting the circuit. A manual reset button is provided to reactivate the temperature limit once the high-temperature condition subsides, ensuring system integrity post-event.
Understanding Bimetal Technology
The operation of Firestat switches relies on bimetal technology. This involves the fusion of two dissimilar metals with distinct coefficients of thermal expansion. As the temperature rises, the bimetal coil undergoes differential expansion, causing it to trigger and open the switch contacts. This enables precise temperature sensing without the need for external power sources or complex software algorithms.
Switch Mechanism and Manual Reset Procedure
Within Firestat switches, the bimetal coil serves as the core component responsible for opening the contacts upon temperature escalation. Following activation, the contacts remain open until a manual reset is performed. This reset process can only occur once the bimetal temperature falls below the predefined threshold. The manual reset button reinstates the temperature limit, ensuring that human intervention is required to verify the elimination of hazardous conditions before system restoration. This deliberate reset prevents premature reactivation and mitigates potential risks associated with automatic resets.
Firestat duct limit controls offer a layer of safety in HVAC systems, particularly in environments where fire detection and prevention are important. By leveraging bimetal technology and incorporating manual reset features, these controls provide reliable and robust protection against temperature-related hazards.
