A method of monitoring a flame rod of a furnace including: detecting an average current of the flame rod during a burn cycle of the furnace; determining a burn time of the burn cycle of the furnace; and determining a remaining life of the flame rod based on at least the average current and the burn time.

A cooktop defining comprises an open loop gas burner, a closed loop gas burner, a flame rectification circuit for detecting a flame at the closed loop gas burner, a spark module comprising a plurality of spark electrodes, at least one of the plurality of spark electrodes being operably coupled to each of the open loop gas burner and the closed loop gas burner, and a controller in operative communication with the flame rectification circuit and the spark module. The controller is configured to determine that the closed loop gas burner is performing the closed loop cooking operation, determine that no flame is present at the closed loop gas burner using the flame rectification circuit, and operate the spark module to energize the plurality of spark electrodes in response to determining that no flame is present during the closed loop cooking operation.

A gas-powered appliance includes a main burner for burning gas, a flame sensor assembly, and a controller. The flame sensor assembly includes a probe positioned proximate the main burner and a detector coupled to the probe to receive an alternating current (AC) input, couple the AC input to the probe and generate a variable pulse width direct current (DC) square wave output having a plurality of pulses. The controller connected is to the flame sensor assembly and includes a processor and a memory. The controller is programmed to control the main burner to burn gas, determine a pulse width of a pulse of the DC square wave, and determine based on the determined pulse width a characteristic of the flame on the main burner with greater precision than some known systems.