Aprilaire® Fan Relay, For Use With: Aprilaire® Model 700A and 700M Humidifiers, 24 VAC Coil
The Aprilaire® 4740 humidifier fan relay is a replacement relay that powers up the circulator fan in the latest Aprilaire® 700 model, 700A and 700M humidifiers. Newer versions of the 700 model series uses an external transformer to power the control circuit along with the Aprilaire® fan relay. Older versions used part number 4238 that contained a small circuit board with a low voltage transformer.
