How Does a Furnace Flame Sensor Work?
Heat of the Flame Flame sensors, whether they are used in a home furnace or on a large industrial boiler, indicate the presence of a flame and are part of the safety circuit. If the flames go out and the furnace or boiler continue to feed the unit with fuel, a catastrophic explosion could occur. The flame sensor sends an electrical signal to a central controller. This central controller operates the gas or fuel valves for releasing the combustible materials into the burning chamber of the furnace or boiler. Upon an initial signal, the flame sensor is placed on a timer. During this “ignition period” the reading from the flame sensor is ignored until a large flame can be “seen” by the sensor. Once the timer has elapsed, the signal from the flame sensor is then constantly read as to monitor the burning of the combustible materials. Metal Strips or Optical There are two basic types of flame sensors: a bi metallic strip and an optical reader. Both of these sensors will output a small voltag
