Why heater coils glow?
It sounds like you're describing one of two things. The hot surface ignitor in a gas-fired furnace, or the resistive heat strips in an electric furnace.
The hot surface ignitor in a gas-fired furnace lights the burners. This ignitor in modern furnaces serves the same purpose as the standing pilot flame did in older furnaces. It provides the required heat to ignite the gas at the burners. Without an ignition source, a gas-fired furnace cannot provide heat. When the ignitor is activated it will glow bright orange or yellow.
The resistive heat strips in an electric furnace actually provide the heat to a home or building. When the furnace turns on, the heat strips are activated and usually glow orange when they reach peak temperature. In almost all cases, the heat strips are not easily seen or accessed without removing covers or panels inside the furnace.
Feb 28, 2011 |
Heating & Cooling