How to Install a GeneralAire 1042-L Humidifier

Attach the GeneralAire 1042-L's template against the air-conditioning system's return air duct above the blower housing, using masking tape. The humidifier's horizontal bypass duct must not obstruct the blower housing's access panels.

Place a pencil mark on the supply plenum level with the template's center line, using a bubble level as a guide. The supply plenum mounts to the output side of the blower housing.

Hold the 6-inch collar of the 1042-L's bypass duct against the center of the supply duct and trace its outline with the pencil, using the pencil mark level with the template's center line as a placement guide.

Cut out the 6-inch circle on the supply duct with aviation snips. Set the collar in the hole. Secure the collar to the duct with two of the supplied mounting screws and a Phillips screwdriver.

Cut out the rectangular center of the template with the aviation snips.

Place the evaporator pad into the slot in the bottom of the humidifier. Mount the drain pan to the bottom of the 1042-L with four mounting screws. Tighten the screws with the Phillips screwdriver.

Hold the 1042-L humidifier against the return duct with its 6-inch-round duct facing the 6-inch-round hole in the supply duct. Attach the 1042 to the duct with eight mounting screws and a Phillips screwdriver. Two screws hold each corner.

Push the 6-inch duct elbow, the duct bent at a 90-degree angle, onto the supply duct's collar. Slip the straight section of bypass duct between the duct elbow and the duct collar on the humidifier. Secure the 6-inch bypass duct and its elbow to the collars with the remaining mounting screws.

Push the end of the water-supply pipe into the intake side of the 1042 humidifier's solenoid, the water valve mounted on the opposite side of the 1042 from the 6-inch duct. The solenoid's intake faces the bottom. Tighten the solenoid's compression nut with an adjustable wrench.

Connect the distributor tube to the solenoid's output and the humidifier's water intake port, located on top of the 1042-L housing. Tighten both compression nuts with the adjustable wrench.

Slip the humidifier's 5/8-inch drain hose onto the drain pan's spigot. Angle the hose toward a floor drain.

Wrap one of the humidistat's low-voltage wires around either solenoid wire terminal. Tighten the terminal with the Phillips screwdriver. Bend the second humidistat wire around the second solenoid wire terminal and tighten the terminal with the screwdriver.