Carrier HH18HA449 Rollout Switch

The Carrier HH18HA449 Rollout Switch is a critical safety component designed to detect and respond to flame rollout conditions in gas-fired furnaces. This genuine OEM part serves as the advanced replacement for the obsolete HH18HA350, ensuring full compatibility with a wide range of Carrier, Bryant, and Payne heating systems. Engineered as a Single-Pole, Single-Throw (SPST) switch, it features a factory-calibrated trip point of 350 degrees F. When the burner compartment temperatures exceed this specific thermal limit, the internal circuit opens to interrupt the furnace's operation, preventing potential fire hazards or equipment damage. This HH18HA449 rollout switch is a manual reset model, a deliberate safety design that requires a technician to inspect the heat exchanger and flue for obstructions or cracks before restoring system power. Its surface-mount housing and durable construction make it a standard choice for furnace safety limit maintenance and HVAC rollout switch replacement tasks.

• Precise Thermal Protection: Calibrated to trigger at exactly 350 degrees F to provide immediate circuit interruption during a flame rollout.
• Direct OEM Compatibility: Functionally replaces several legacy versions, including the HH18HA350 and HH18HA250, maintaining the original equipment’s safety integrity.
• Verified Safety Logic: The manual reset feature ensures the system cannot be restarted until the root cause of the overheat has been professionally diagnosed and addressed.
• Robust SPST Design: High-reliability Single-Pole, Single-Throw switching action provides consistent performance in high-amperage heating circuits.

How do I know if the rollout switch is tripped?
If your furnace has power but won't initiate the ignition sequence, check the small red button on the back of the HH18HA449. If it clicks when pressed, the high-limit switch had been tripped by excessive heat.

Can I swap this for a switch with a different temperature rating?
No. For safety and compliance, always use the 350F rollout switch specified by the manufacturer. Installing a switch with a higher rating can bypass critical safety windows.

Why does my rollout switch keep tripping?
Frequent tripping is usually a symptom of a cracked heat exchanger, a blocked vent pipe, or low gas pressure. The Carrier HH18HA449 is doing its job; the underlying airflow or combustion issue must be resolved by a technician.

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.