Carrier HH12ZB220 Limit Switch

The Carrier HH12ZB220 Limit Switch is a critical safety component designed for high-limit protection in residential furnaces, packaged units, and air handlers. Engineered as a normally closed (NC) switch, this part initiates a system cutout when the 220F open temperature is reached, effectively preventing heat exchanger damage and hazardous operating conditions. Once the plenum cools to the 180F close temperature, the bimetal disc automatically resets, allowing the control board to resume the heating cycle. With a 3.12-inch insertion length, this switch provides accurate sensing deep within the supply air stream. It is a direct OEM replacement for Carrier, Bryant, and Payne equipment, ensuring the precise physical fit and electrical calibration required for safety-rated circuits. Replacing a cycling or stuck furnace high limit switch with this factory-authorized part restores the reliability of the overheat protection system and prevents common issues like furnace short cycling or the blower fan running continuously. Key Benefits

• Factory-Calibrated Safety: Precise 220-degree cut-out protects the heat exchanger from thermal stress.
• Automatic Reset: Returns to a closed state at 180 degrees Fahrenheit without manual intervention.
• Broad Compatibility: Replaces legacy part numbers HH12ZA219, HH12ZA223, and P331-2206.
• Technical Build: Durable 3.12" L220-40F construction designed for high-duty cycles in gas-fired systems.

What causes a limit switch like the HH12ZB220 to trip frequently?
Repeated tripping is usually caused by restricted airflow. Check for a clogged furnace filter, blocked registers, or a malfunctioning blower motor that isn't moving enough air across the heat exchanger.

How do I test the HH12ZB220 for a fault?
Under normal room temperature conditions, use a multimeter to check for continuity across the terminals. Since this is a normally closed switch, an open reading at room temperature indicates the internal bimetal disc has failed.

Can I use a switch with a different temperature rating?
No. In HVACR applications, you should always match the OEM temperature specifications. Using a higher limit can lead to unsafe cabinet temperatures, while a lower limit will cause short cycling and premature wear on the inducer and gas valve.

This item is not eligible for free shipping.

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.