Carrier HH18HA211 Rollout Switch

The Carrier HH18HA211 Rollout Switch is a critical safety component designed for Carrier, Bryant, and Payne furnaces and packaged units. As a high-limit safety device, it monitors for flame rollout conditions—where burner flames escape the combustion chamber—and immediately interrupts the 24V control circuit to prevent equipment damage or fire hazards. This OEM replacement part features a snap-disc design with a Single Pole Single Throw (SPST) configuration, ensuring a reliable, normally closed connection during standard operation. With a precision 225°F open temperature and a 175°F close temperature, the switch provides an automatic reset capability, allowing the system to resume operation once temperatures return to a safe range. This rollout limit switch is engineered to meet the exact specifications of original factory components, maintaining the integrity of the furnace's safety string and ensuring seamless compatibility with existing wiring harnesses.

• Factory-spec safety: Specifically calibrated to open at 225 degrees F, providing a precise response to dangerous combustion conditions.
• Automatic reset functionality: Eliminates the need for manual intervention by closing the circuit once the unit cools to 175 degrees F.
• Direct OEM compatibility: Designed as a direct drop-in replacement for Carrier HH18HA211, ensuring a perfect fit in 581JE and similar furnace models.
• Robust SPST construction: Features a durable snap-disc mechanism for high-cycle reliability in demanding HVAC environments.

What causes a rollout switch like the HH18HA211 to trip?
A trip usually indicates a restriction in the heat exchanger, a blocked flue/vent, or issues with gas pressure and burner alignment. Always inspect the heat exchanger for cracks if this safety switch opens frequently.

Is the HH18HA211 compatible with other brands?
Yes, besides Carrier, this part is a standard thermal safety component for many Bryant and Payne gas furnaces and rooftop units that require a 225F/175F temperature profile.

Can I test this switch for continuity?
Yes, at room temperature, the Carrier HH18HA211 should show continuity across the terminals since it is a normally closed (NC) switch. If it shows an open circuit when cool, the internal disc is likely defective and requires 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.