A.O. Smith Tank GCG-50-NG
A.O. Smith Tank GCG-50-NG
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A.O. Smith ProLine® - 50 Gal. Storage - 81 Gal. First Hour Delivery - 0.62 UEF - Natural Gas Water Heater - Atmospheric Vent - Tall



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A.O. Smith ProLine® - 50 Gal. Storage - 81 Gal. First Hour Delivery - 0.62 UEF - Natural Gas Water Heater - Atmospheric Vent - Tall
A.O. Smith ProLine® - 50 Gal. Storage - 81 Gal. First Hour Delivery - 0.62 UEF - Natural Gas Water Heater - Atmospheric Vent - Tall
Model: GCG-50-NG
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Recommended Accessories

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Expert Recommended Accessories Selected by Bob, our Expert
Required Accessories 9
These accessories are required to properly setup/install this product.
Optional Accessories 10


    A.O. Smith has led the way in innovative hot water solutions for nearly 80 years. With unmatched quality and diversity, A.O. Smith can provide hot water anywhere it's needed. The A.O. Smith ProLine® series features an internal microprocessor that provides improved operating parameters for precision sensing and fast heating response. With a patented Green Choice® gas burner, the ProLine® has an eco-friendly design that reduces NOx emissions by up to 33%. The ProLine® water heater maximizes hot water output with the DynaClean™ diffuser dip tube by reducing lime and sediment buildup. Featuring a CoreGard™ anode rod with a stainless steel core, the A.O. Smith ProLine® series has an extended life due to superior tank protection.
  • Intelligent Control Logic
  • Providing enhanced operating parameters, the internal microprocessor in the ProLine provides precise sensing and faster heating response.
  • Green Choice Burner
  • The patented, eco-friendly burner helps to reduce NOx emissions by up to 33% and complies with Low NOx emission requirements.
  • DynaClean
  • With a DynaClean diffuser dip tube that reduces lime and sediment buildup, the ProLine has maximized hot water output.
  • CoreGard
  • Extending the life of your tank, the CoreGard anode rod has a stainless steel core that provides superior tank protection compared to standard rods.
  • Push-Button Piezo Ignitor
  • The ProLine features a one-hand, push-button piezo ignitor, making it simple to light the pilot.
  • Glass Coating
  • Featuring Blue Diamond glass coating, the ProLine has better corrosion resistance compared to standard glass lining.
  • Eco-Friendly
  • The ProLine features foam insulation, external heat traps and a specially designed combustion chamber. These combined produce a high UEF for savings on operating costs.
  • Brass Drain Valve
  • The solid brass, ball type, tamper resistant drain valve on the A.O. Smith ProLine provides enhanced flow. Use with a standard female hose fitting for simple draining and maintenance.
  • Warranty
  • 6 Year Parts
  • 6 Year Tank


specs product image PID-117131
Product Category
Water Heater - Tank
General Information
Gas Water Heater
Product Line
Product Category
Water Heater - Tank
Delivery Options
Pickup Only
Medium Learn More
Medium refers to the substance that carries heat through the heating system. Systems are either designed to use either Hot Water or Steam as a medium, and components are usually specific to one or the other.
Hot Water
Fuel Type Learn More
Fuel Type
To create heat, some form of fuel is required. Fuel Type specifies what the product uses as an input to create heat.
Natural Gas
Combustion Type Learn More
Combustion Type
Condensing appliances use leftover thermal energy from combustion gases to heat water in a secondary heat exchanger, resulting in higher efficiency and lower exhaust temperature.
Single Stage
Vent Type Learn More
Vent Type
Products that use combustion (burning) of fuel to create heat also create potentially dangerous gasses that need to be exhausted (AKA "Vented"). Depending on the product, venting can be done via a chimney, through a side wall, or use a second vent to provide fresh air to the appliance.
Storage Type
Mount Type
Maximum Altitude
10100 Feet
Maximum Input Capacity Learn More
Maximum Input Capacity
The Maximum Input Capacity describes how quickly the appliance will use fuel when delivering it's maximum capacity. The units may change depending on the fuel being used.
40000 BTU
First Hour Delivery Learn More
First Hour Delivery
Sometimes called First Hour Rating, this is the number of gallons of hot water the heater can supply per hour when starting with a fully heated tank. The recovery of the water heater depends on your boiler's BTU and boiler output temperature.
81 Gallons
Uniform Energy Factor Learn More
Uniform Energy Factor
Uniform Energy Factor (UEF) is a measurement of water heater energy efficiency. The higher the energy factor, the more efficient the water heater.
Low NOx Emissions Learn More
Low NOx Emissions
NOx is a byproduct of the combustion process, and it's output is regulated in some jurisdictions. Many regulators mirror SCAQMD rules, which regulate air quality for some parts of Southern California. Low NOx appliances emit less than 40 ng/J (nanogram per Joule) of NOx. Learn More
Storage Volume
50 Gallons
Cold Water Inlet
3/4 Inch
Hot Water Outlet
3/4 Inch
Product Height
60 3/4 Inches
Product Width
21 Inches
Product Depth
21 Inches
Shipping Weight
148 Pounds
CSA Listed
AHRI Certified
AHRI Reference Number
Warranty Information
Parts Warranty Learn More
Parts Warranty
A warranty is a safeguard from defects in manufacturing and can vary in length and terms. Some manufacturers require registration for extended warranty benefits, be sure to check out features and the warranty document. To see the manufacturer's warranty statement, click on the Manuals tab. Learn More
6 Years
Vessel Warranty
6 Years


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A.O. Smith ProLine® - 50 Gal. Storage - 81 Gal. First Hour Delivery - 0.62 UEF - Natural Gas Water Heater - Atmospheric Vent - Tall
A.O. Smith Tank GCG-50-NG
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