Furnace Pressure Switches

Furnace Pressure Switches

Furnace pressure switches typically consist of an elastomeric diaphragm, insulators and field adjustable pressure set points. When a furnace pressure switch is actuated an elastomeric diaphragm moves and opens or closes an electrical circuit that interrupts or continues the flow involved.  An elastomeric diaphragm eliminates the need for an oil barrier because they separate pressure instruments from the process media, while allowing the instruments to sense the process pressure. The insulators are designed as a protective barrier against direct exposure to live parts. A furnace pressure switch is set to a certain point of pressure to which it will automatically respond. Field adjustable pressure set points allow the furnace pressure switch to be calibrated to the correct pressure points for opening and closing the diaphragm. There are three main types of furnace pressure switches: air pressure switches, water pressure switches and fuel pressure switches. An air pressure switch ensures that there is enough fresh air circulated through the furnace. A water pressure switch is used in furnaces that heat water and protect the water heater tank from burns. A fuel pressure switch monitors the pump’s ability to produce enough pressure for the liquid fuel oil to be squeezed into a fine mist through a nozzle for full combustion.