York HU12MB is a humidifier that can be installed on either the supply or return plenum of a forced air handling system. It is reversible for installation with bypass duct connections on the right or left side of the cabinet. The outer dimensions of the cabinet are 13 1/2” wide, 15” high X 9 1/2” deep. The S1-HU12MB is a self-contained unit that includes a solenoid valve, a water distributor tube, a distributor trough, an evaporator pad, and a drain pan. The unit is designed to operate with a 1/4" water supply line and a 24-volt power supply. The S1-HU12MB has a flow rate of approximately 3.