Rheem-Ruud 62-21426-02 Mercury Flame Sensor Switch - Plug-In

The Rheem-Ruud 62-21426-02 is a plug-in mercury flame sensor switch designed for gas furnace pilot safety applications. This genuine OEM replacement part provides critical flame detection to ensure safe operation of your heating system.

How It Works:

This mercury flame sensor uses a mercury-filled sensing bulb connected via a capillary tube to a diaphragm and snap-action switch mechanism. When the pilot flame heats the sensing bulb, the mercury vaporizes and expands, actuating the switch to signal that the pilot is lit. This allows the main gas valve to open safely for burner operation.

Key Features:

• Genuine Rheem-Ruud OEM replacement part
• Plug-in design for easy installation without point-to-point wiring
• Mercury-filled sensing bulb provides reliable flame detection
• Snap-action switch mechanism ensures positive on/off operation
• Designed for cycle pilot systems with electronic ignition
• Prevents main burner operation if pilot flame is not present

Important Safety Note:

This component must be installed by a qualified HVAC technician. Mercury flame sensors are critical safety devices that prevent gas leaks by ensuring the pilot flame is present before allowing main burner operation. Proper installation and testing with calibrated combustion equipment is essential for safe operation.