Description
The Rheem-Ruud 47-21776-86 Defrost Control Board Kit is a device that is required in frost control for some Rheem-Ruud furnaces. It is a circuit board assembly that regulates the defrosting process that helps to avoid formation of ice on the evaporator coil during cold climate operation. Here is how it works: In heating mode the evaporator coil takes heat from the outside air and brings cool air inside the furnace. Exterior air humidity can drip or freeze on the evaporator coil and cause the formation of frost. Such ice accumulation hampers the flow of air and hinders the ability of the furnace to pull out heat effectively.
