Furnace Blower Furnace Fan Limit Switch Wiring Diagram

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.

Furnace blower furnace fan limit switch wiring diagram.

This control can be wired to serve as a safety limit switch on a furnace by wiring just the limit terminals on the control. Honeywell furnace temperature fan limit switch control the fan limit control turns the fan on and off in furnace applications. 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. Remove the wires attached to the old fan limit control.

That will cause the burners or heat source to shut off and the fan to run until the limit switch closes again. Assortment of furnace fan motor wiring diagram. 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. If the furnace overheats then a limit switch will open.

A helical bi metal probe extends from the back of the. Furnace fan motor wiring diagram wiring diagram for fasco blower motor valid blower motor wiring diagram lovely furnace blower motor wiring. In some cases the limit switch will stick open and this will cause the fan to run continuously. 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.