General Filters 12500 ERP_071034

General Filters Air Pressure Proving Switch, 1/4 in Tube ID, 3/8 in Tube, 2-9/16 in Switch OD Dia, 71-1/2 in L Tube

• The 12500 air pressure switch senses furnace operation, in furnaces with a two speed blower motor
• The switch then supplies power to the humidifier accordingly
• Prevents operation of the humidifier if there is no air flow in the duct, thereby preventing moisture build-up in the duct system
• Range 1/2 in WC