Magnesium Anode Rod 3/4” x 42” Hex Plug – Rheem AP12938 – NBK-21027

Magnesium Anode Rod 3/4” Hex Plug 3/4” x 42” – NBK-21027

The NBK-21027 Magnesium Anode Rod is a critical corrosion-protection component designed for outdoor boilers and water heater systems. Anode rods help extend tank life by attracting corrosive elements in the water, reducing rust and deterioration inside the tank.

This unit features a 3/4” hex plug and measures 3/4” x 42 inches, making it a direct replacement for Rheem AP12938 and compatible equivalents such as Grainger models.

Key Features

• Magnesium Construction: Provides superior corrosion protection in water systems
• 3/4” Hex Plug Fit: Standard connection for many boiler and heater tanks
• 42” Length: Designed for full tank coverage and extended service life
• OEM-Compatible Replacement: Direct replacement for Rheem AP12938

Specifications

• SKU: 21027
• Category: Outdoor Boiler
• OEM Brand: Rheem
• Material: Magnesium
• Plug Type: 3/4” Hex Plug
• Rod Size: 3/4” Diameter x 42” Length
• Replaces OEM: AP12938

Equivalent To

• Rheem: AP12938
• Grainger: 45W630

Why Choose the NBK-21027?

The NBK-21027 magnesium anode rod is an essential maintenance part for protecting outdoor boiler and water heater tanks from corrosion. Replacing worn anodes helps prevent premature tank failure and supports long-term system performance.

Installation Tips

• Turn off water heater or boiler and allow system to cool before servicing.
• Relieve tank pressure before removing the existing anode rod.
• Use thread sealant or plumber’s tape for proper installation.
• Inspect anode condition annually for best tank protection.

Pairs Well With

Outdoor Boiler Treatment Chemicals, Replacement Gaskets, Water Heater Drain Valves, Tank Maintenance Kits

SPECIAL ORDER NOTICE: This item is sourced through our special order program. Please allow 1–2 business days for processing prior to shipment.