Rheem-Ruud 47-104990-03 L170-20F Auto Reset Limit Switch SPST Normally Closed

The Rheem-Ruud 47-104990-03 is a genuine OEM replacement limit switch designed for use in Rheem and Ruud gas furnaces and HVAC heating systems. Rated at L170-20F, this safety switch monitors heat exchanger temperatures and automatically shuts off the burner if an unsafe temperature is reached, protecting the system from overheating damage.

Key Specifications:

• Model / Rating: L170-20F
• Switch Type: SPST (Single Pole, Single Throw)
• Circuit Configuration: Normally Closed
• Opens On: Temperature rise at 170°F
• Reset Type: Automatic (Auto Reset)
• Insert Length: 3 inches
• OEM Part Number: 47-104990-03

Features & Benefits:

• Genuine OEM Rheem-Ruud replacement part — ensures proper fit and function
• Automatic reset operation restores normal furnace operation once temperatures return to safe levels
• Normally closed design keeps the circuit complete during normal operation, opening only on overtemperature events
• 3-inch insert depth suitable for standard Rheem/Ruud furnace heat exchanger applications
• Direct OEM replacement — no modification required

This limit switch is a critical safety component in gas furnaces, protecting against overheating conditions that could cause system damage or create hazardous situations. It is sold as a single unit and is compatible with a wide range of Rheem and Ruud gas furnace models.