A.o. Smith 100074625 Bypass Valve Tankless Water Heater

Product Description

The A.O. SMITH 100074625 is a replacement bypass valve designed for use in tankless water heater systems. The bypass valve controls or diverts water flow within the unit, playing a direct role in maintaining proper hydraulic balance and system performance. It is a factory-style replacement part intended to restore original function when the original valve fails or is damaged. Licensed plumbers and qualified HVAC-plumbing technicians are the typical installers for this component.

This bypass valve is a direct replacement part for a range of A.O. SMITH tankless water heater models, covering both natural gas and liquid propane configurations. It fits residential and light-commercial tankless units across several product families, including indoor and outdoor installations. The compatible model list spans both standard and power-vented configurations, making this valve a versatile service part for technicians who work across multiple A.O. SMITH tankless platforms.

Key Features

• OEM-style replacement part for A.O. SMITH tankless water heaters
• Compatible with both natural gas and liquid propane models
• Fits indoor and outdoor tankless unit configurations
• Restores proper flow control and hydraulic balance within the system
• Direct-fit design reduces installation time on compatible units

Compatibility

Compatible with the following A.O. SMITH tankless water heater models: T-H3-OS (NG), T-H3-OS (LP), T-H3-DV (NG), T-H3-DV (LP), TK-510U-E (NG/LP), TK-510U-I (NG/LP), T-D2U-OS (NG), T-D2U-IN (NG), TK-540P-NEH (NG), TK-540P-NIH (NG), TK-540P-PIH (LP), TK-540P-PEH (LP), TK-510C-NI (NG).

Installation Notes

Installation should be performed by a licensed plumber or qualified technician familiar with tankless water heater service. Shut off the cold water supply and disconnect power or gas to the unit before beginning any valve replacement work. Follow the manufacturer service documentation and applicable local plumbing codes for proper procedure. Do not restore water pressure or relight the unit until all connections are verified leak-free.

Technical Specifications

• Type: Replacement Part

Standard Information

• Brand: A.O. SMITH
• Manufacturer Part Number: 100074625