The Rinnai 104000192-K Water Heater Flame Rod Electrode Kit detects the presence of a burner flame to support proper water heater operation. This assembly uses a flame-sensing electrode to monitor the burner during operation and send an electrical signal to the ignition control system. When a flame is detected, the signal confirms combustion and allows the system to continue its heati... https://www.hnkparts.com/104000192-k-rennai-kit-flame-rod-electrode-r75/4-104000192-K.html