Rheem-Ruud 47-21711-07 Limit Switch

The Rheem-Ruud 47-21711-07 Limit Switch is a critical safety component designed for high-performance furnace and air handler applications. As a genuine OEM replacement part, this SPST normally closed switch provides reliable thermal protection by monitoring plenum temperatures. It is engineered with a 160-degree F fixed open temperature and a 140-degree F fixed close temperature, ensuring precise cycling and preventing exchanger overheating in residential and commercial HVAC systems. With an extended 7-inch insertion length, this automatic reset limit switch is ideal for deeper cabinet configurations where accurate sensing is paramount. The board-mounted design facilitates a direct, secure integration into existing furnace control assemblies. For technicians troubleshooting high-limit trips or airflow restrictions, this general-purpose limit control ensures the system operates within factory-specified thermal parameters. Utilizing OEM furnace parts like the 47-21711-07 maintains factory listings and ensures long-term reliability in demanding heating and cooling environments.

• Precise Thermal Safety: Fixed 160°F cutout and 140°F cut-in points prevent equipment damage from excessive heat.
• Extended Reach: The 7-inch probe length allows for accurate temperature monitoring in high-profile heat exchangers.
• Seamless Integration: Specifically designed as a board-mounted component for quick replacement in compatible Rheem-Ruud units.
• Automatic Recovery: Features an auto-reset mechanism that restores circuit continuity once temperatures return to 140°F.

What causes a 160-degree limit switch to trip frequently?
Frequent tripping is usually indicative of restricted airflow, such as a dirty air filter, blocked return vents, or a failing blower motor. If the 47-21711-07 technician-verified switch opens, first inspect the temperature rise across the heat exchanger.

Can I use a shorter insertion length for this application?
No. The 7-inch insertion length is specified to ensure the sensor reaches the optimal thermal zone. Using a shorter probe may result in delayed response times or failure to detect a critical overheat condition.

Is the 47-21711-07 compatible with other furnace brands?
While this is a general-purpose limit switch, it is engineered specifically for Rheem-Ruud specifications. Always verify the part number against the equipment's schematic to ensure proper HVAC part compatibility.

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.