Ruud 47-104990-01 Gas Furnace Limit Switch 125-145 Auto Reset

Product Description

The RUUD 47-104990-01 is a single-pole, single-throw (SPST) auto-reset limit switch designed for residential gas furnace applications. Rated at 120/230 VAC and 15/10 amps, this normally closed switch opens at 145 degrees F and resets automatically when the temperature drops back to 125 degrees F. It is a critical safety component that protects the heat exchanger and surrounding components from overtemperature conditions. Licensed HVAC technicians install this switch as part of routine furnace maintenance or when diagnosing nuisance lockouts caused by a failed limit device. The black/red wire designation aids in correct field identification during replacement.

This limit switch is used in residential gas furnace systems where thermal protection and automatic recovery are required. It is specified for use on the R801CA050314MSA and R801CA050314MXA gas furnaces. Its auto-reset function eliminates the need for manual intervention after a high-temperature event, provided the root cause of the overtemperature condition has been corrected. HVAC service technicians replacing a failed or out-of-calibration limit switch will find this a direct OEM-replacement option for the listed furnace models.

Key Features

• Auto-reset operation: opens at 145 degrees F, closes at 125 degrees F
• SPST, normally closed, 1-pole configuration
• Dual voltage rating: 120/230 VAC at 15/10 amps
• Black/red wire identification for field installation reference
• Direct OEM-style replacement for listed RUUD gas furnace models

Compatibility

Designed for use on the RUUD R801CA050314MSA and R801CA050314MXA gas furnaces per manufacturer specification.

Installation Notes

Installation should be performed by a licensed HVAC technician. Disconnect power to the furnace and shut off the gas supply before servicing any limit switch. Verify the replacement switch is positioned correctly in the airstream and that all wiring terminals are fully seated before restoring power. After installation, investigate and correct any underlying cause of overtemperature operation such as restricted airflow or a dirty filter before returning the system to service.

Technical Specifications

• Switch Type: SPST, Normally Closed, Auto Reset, 1-Pole
• Open Temperature: 145 degrees F
• Close Temperature: 125 degrees F
• Voltage Rating: 120/230 VAC
• Current Rating: 15/10 amps
• Wire Color: Black/Red
• Height: 2.1 inches
• Length: 5.6 inches
• Width: 3.05 inches
• Weight: 0.09 pounds

Standard Information

• Brand: RUUD
• Manufacturer Part Number: 47-104990-01