Description
The Lennox 20J91 Flame Sensor is an ignition control part of gas-fired furnaces and boilers and its main role is flame detection. This is a flame sensor going by the ultraviolet light principle even though it is a pretty small device. In normal working conditions, the furnace is on and the flame is giving out UV light. This sensor converts it to an electrical 2signal to the control board of the furnace or boiler. If the flame is out or not functioning, the sensor does not pick up the UV light, and the control board off the gas.
