A. O. Smith 16" Final Burner Assembly Natural Gas #37 Orifice — OEM Replacement for Water Heaters

The A. O. Smith 100112342 is a 16-inch natural-gas final burner assembly fitted with a #37 orifice, designed as a factory-style replacement for compatible water heater models.

If your water heater needs the terminal burner component that controls the flame and gas flow, this replacement assembly restores proper combustion performance and fits into systems engineered for A. O. Smith parts. It’s a direct-fit final burner assembly specified for natural gas use, sized 16 inches with a #37 orifice to match the original manufacturer's flow characteristics.

What does this final burner assembly do for my water heater?

This assembly is the last stage in the burner system where fuel and air mix and ignite to heat the water. Installing the correct final burner ensures stable flame pattern, efficient combustion, and compatibility with the heater’s draft and venting design.

• Replaces worn or damaged terminal burner components.
• Maintains designed flame characteristics and heat output.
• Works with the heater’s existing manifold and pilot/ignition setup.

How do I confirm compatibility with my unit?

Match the part number and physical dimensions to your heater’s service manual or the current component. Confirm the fuel type (natural gas), the 16-inch length, and the #37 orifice size to ensure a correct swap.

• Check your water heater model and parts list for A. O. Smith 100112342.
• Verify the burner length is 16" and the orifice code is #37.
• Compare mounting points and connector types before installation.

What should an installer know before replacing the burner?

A qualified technician should perform the replacement, following local codes and the manufacturer’s service instructions. Proper gas shutoff, leak testing, and combustion adjustment are essential for safe operation after installation.

• Shut off gas and power, and ensure the appliance is cool before work begins.
• Test for leaks after reassembly and set combustion as specified by A. O. Smith.
• Keep replacement components OEM or equivalent for warranty and performance reasons.

Will changing the orifice or burner affect performance?

Yes — orifice size and burner geometry directly influence gas flow rate and flame shape. Use the specified #37 orifice and the correct 16" burner to maintain manufacturer-intended combustion and heating efficiency.

• Do not substitute different orifice sizes without recalibration by a professional.
• Incorrect burner length or orifice can cause poor combustion or safety issues.
• OEM-matched parts preserve operating parameters and regulatory compliance.

This final burner assembly is suited for installers, maintenance technicians, and facilities managers who service A. O. Smith natural-gas water heaters and need a reliable OEM replacement. Choose this part when you require the same specifications as the original equipment — 16-inch length, natural gas configuration, and a #37 orifice — to restore proper burner operation and maintain safe, efficient heating.