Furnace Blower Furnace Fan Limit Switch Wiring Diagram

Assortment of furnace fan motor wiring diagram.

Furnace blower furnace fan limit switch wiring diagram.

That will cause the burners or heat source to shut off and the fan to run until the limit switch closes again. In some cases the limit switch will stick open and this will cause the fan to run continuously. Remove the wires attached to the old fan limit control. If the furnace overheats then a limit switch will open.

It works off of temperature and also provides a high temperature safety limit this is a switch actually two switches which turns the furnace blower on and off based on the temperature of the heat exchanger. When the device is used both to control a furnace fan on and off as well as serve as a limit switch then all four terminals are. This control can be wired to serve as a safety limit switch on a furnace by wiring just the limit terminals on the control. This article describes in detail the purpose operation setting installation wiring and testing of furnace combination controls also commonly called the fan limit switch on warm air heating systems.

Mac 1175 wiring diagram mgh furnace wiring diagram models mg auxiliary limit control at bottom of heat exchanger green ground screw control panel cover 3 2 1 blower receptacle 3 2 1 fan off on 3 position switch black white. Limit switch issue furnace blower fan wont turn off. Wiring the furnace combination fan limit control using the honeywell l4064b as an example. Furnace blower fan limit safety switch installation troubleshooting.