4655 Aprilaire Manual Humidistat.Features. For use with Aprilaire models 110 112 220 224 350 360 400 440 445 445A 448 500 550 558 560 560A 568 700 760 760A and 768.. Can be wall mounted or mounted on return plenum plenum cutout templet included.. For duct mount locate at least 6 in. upstream of humidifier humidifier bypass ductwork or fresh air intake ductwork.. Designed for low voltage service to control humidification equipment.. An increase in relative humidity expands the nylon ribbon which opens the control switch to stop operation of the humidifier.. A decrease in relative humidity reverses the process and closes the control switch.

Aprilaire US4655 Manual Humidistat - B00RG0Y0MG