Carrier HH18HV135 Limit Switch

The Carrier HH18HV135 Limit Switch is a critical OEM replacement part designed for high-limit thermal protection in residential and commercial HVAC systems. This disc-style sensor features a normally closed (NC) configuration that triggers an open circuit at 135°F to prevent heat exchanger damage or unsafe operating conditions. Once the temperature drops to 110°F, the automatic reset capability restores the circuit, ensuring continuous system operation without manual intervention. As a factory authorized part, it maintains the precise calibration required for Carrier, Bryant, and Payne furnaces and air handlers. Engineered with a rugged housing and a compact disc style design, the HH18HV135 provides reliable switching performance in demanding environments. This switch serves as a direct drop-in for legacy part numbers including HC18HV135 and HH18HV135-B. Utilizing genuine OEM furnace parts like this limit control ensures proper HVAC compatibility and maintains the original engineering profile of the heating equipment.

• Precise Thermal Control: Engineered for fixed 110-135F temperature setpoints to ensure high-limit safety.
• Automatic Reset Function: Reduces service calls by automatically resetting the furnace limit switch once ambient temperatures stabilize.
• Broad Compatibility: Matches specifications for a wide range of Carrier, Bryant, and Payne replacement parts.
• Durable Construction: Built to withstand the thermal cycling typical of modern high-efficiency heating and cooling units.

• What does a 135-degree limit switch do? It acts as a safety sensor that shuts down the burner if it detects temperatures exceeding 135°F, protecting the blower and heat exchanger.
• Will this work with my Carrier furnace? This genuine Carrier part is compatible with many models; checking the model number against the HH18HV135 specification is recommended.
• How do I test a limit switch? Using a multimeter to check for continuity while the switch is cool will confirm if the normally closed circuit is intact.

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.