Ao Smith 100109908 Flame Sensor Kit

Product Description

The AO SMITH 100109908 is a flame sensor kit designed for use in gas-fired water heating systems. The flame sensor monitors burner operation by detecting the presence of an established flame through the principle of flame rectification. When the control board no longer receives a valid signal from the sensor, it shuts down the burner to prevent unsafe operation. This kit is installed by licensed plumbers and HVAC technicians during routine maintenance or when a faulty sensor causes nuisance lockouts or ignition failures.

This flame sensor kit is suited for residential gas water heater applications where the original sensor has degraded, corroded, or failed. Flame sensors are a common service item and are typically replaced when the unit experiences repeated ignition lockouts, erratic burner cycling, or fault codes pointing to a flame-sensing failure. Install this kit as part of a scheduled service call or during a burner assembly inspection.

Key Features

• Direct replacement flame sensor kit for gas water heater service
• Monitors burner flame via flame rectification signal to the control board
• Helps resolve nuisance lockouts and ignition fault codes
• Designed for straightforward field replacement during routine maintenance

Compatibility

Designed as an OEM-style replacement flame sensor kit for AO SMITH residential gas water heaters. Refer to the unit service manual or AO SMITH parts lookup to confirm fitment for your specific model before installation.

Installation Notes

Installation should be performed by a licensed plumber or HVAC technician familiar with gas appliance service. Shut off the gas supply and disconnect power to the water heater before beginning any service work. Handle the sensor rod carefully to avoid contaminating the sensing tip with oils or debris, as surface contamination can degrade the rectification signal. Follow all applicable local codes and the manufacturer service documentation during reassembly.

Technical Specifications

• Product Type: Flame Sensor Kit

Standard Information

• Brand: AO SMITH
• Manufacturer Part Number: 100109908