A.o. Smith 100076303 Fkm O-ring Water Heater Seal

Product Description

The A.O. SMITH 100076303 is an FKM O-ring replacement seal designed for use in A.O. Smith tankless water heater units. FKM (fluoroelastomer) material provides strong resistance to heat, fuels, and water-borne chemicals, making it a reliable choice for sealing applications in high-temperature water heating systems. This O-ring maintains a leak-free seal at critical connection points within the unit. Licensed plumbers and HVAC technicians performing service, repair, or routine maintenance on compatible A.O. Smith tankless models will install this part.

This O-ring is specified for use across a broad range of A.O. Smith tankless water heaters, covering both natural gas (NG) and liquid propane (LP) configurations. It is used in residential and light commercial tankless models including indoor, outdoor, direct-vent, and open-combustion unit variants. Refer to the compatibility section for the full list of applicable model numbers provided by A.O. Smith.

Key Features

• FKM (fluoroelastomer) construction for resistance to heat, fuels, and water
• OEM replacement seal for A.O. Smith tankless water heaters
• Compatible with both natural gas and liquid propane model variants
• Maintains leak-free seal at internal connection points during service or repair
• Broad cross-model fitment covering indoor, outdoor, direct-vent, and open-combustion units

Compatibility

Compatible with the following A.O. Smith tankless water heater models: T-M199 (NG), T-M50 (NG), T-H3M-DV (LP), T-H3J-DV (LP), T-M32 (LP), T-H1 (LP), T-H3S-DV (LP), TK-510C-NI (NG), T-H3-DV (LP), T-D2-OS (LP), T-M1 (LP), T-K3-SP (NG), T-H2-OS (NG), T-K3-OS (NG), T-D2-OS (NG), T-KJR2-IN (NG), T-M1 (NG), T-M199 (LP), T-H2-OS (LP), T-H2S-OS (LP), T-D2U-OS (NG), T-KJR (LP), TK-110U-E (NG/LP), T-M50-ASME (NG), T-M50 (LP), T-K1S (LP), T-H3S-DV (NG), T-H2S-DV (LP), T-K4U-IN (NG), T-D2U-IN (NG), TK-310U-E (NG/LP), T-K3-PRO (NG), T-M32 (NG), T-KD20 (LP), TK-510U-I (NG/LP), T-KJR2-OS (LP), T-K4U-OS (NG), T-K4-OS (LP), T-K4-OS (NG), T-K3-PRO (LP), T-H3-DV (NG), T-H2-DV (LP), T-KJR2U-OS (NG), T-D2-IN (NG), T-H3J-OS (LP), T-H3M-DV (NG), TK-540P-NEH (NG), T-H1 (NG), T-K3 (NG), T-H2S-OS (NG), T-KJR (NG), T-M32-ASME (LP), T-D2-IN (LP), T-K2 (LP), T-H3-OS (LP), T-H3J-DV (NG), T-K4-IN (NG), T-H2S-DV (NG), T-K4-IN (LP), T-H3-OS (NG), T-H3M-OS (NG), TK-540P-PIH (LP), T-K3-OS (LP), TK-540P-NIH (NG), T-KJR2U-IN (NG), T-KJR2-OS (NG), TK-110C-NI (NG), TK-310U-I (NG/LP), T-M50-ASME (LP), T-KJR2-IN (LP), T-K3-SP (LP), T-H3M-OS (LP), T-M32-ASME (NG), T-H2-DV (NG), T-H3J-OS (NG), TK-310C-NI (NG), TK-110U-I (NG/LP), T-H3S-OS (LP), T-K2 (NG), TK-510U-E (NG/LP), T-KD20 (NG), T-K1S (NG), TK-540P-PEH (LP), T-K3 (LP), T-H3S-OS (NG).

Installation Notes

Installation should be performed by a licensed plumber or qualified service technician. Shut off the water supply and gas supply to the unit and allow the heater to cool fully before beginning any disassembly. Inspect the seating surface for debris or corrosion before installing the new O-ring to ensure a proper seal. Follow all applicable local plumbing codes and the manufacturer service documentation for the specific model being serviced.

Technical Specifications

• Part Type: O-Ring
• Material: FKM (Fluoroelastomer)

Standard Information

• Brand: A.O. SMITH
• Manufacturer Part Number: 100076303