How to Install an Air Conditioner Fan

air conditioning unit outside a building
What You'll Need
Tape measure
Nut driver
Crescent wrench
Mounting brackets
Drain pan
Brazing kit
Wire nuts
Assorted copper and PVC plumbing

An air conditioner fan, or air handler, is the heart of a central air conditioning system. These units often contain refrigerant coils and heating elements. Their installation requires technical competence in plumbing, electrical wiring, ductwork, and refrigerant line brazing.

Step 1 - Inspect Equipment

Unpack the equipment and check it for damage. Check the ratings on the air handler to verify its compatibility with the exterior unit and thermostat.

Step 2 - Site Unit

man working on an air conditioning unit

Choose an installation location. The unit must be slightly tilted towards the site of the drain pan and drain line. It must be supported from the bottom, either by installing on the floor or hanging from the wall with a metal mounting bracket. Choose a space that allows access to the coil compartment and blower compartment service panels.

Step 3 - Install Ductwork

If installing in a closet, use a closet with a false bottom or install an air return cavity using metal ducting. Connect the vent ducts to the flanges. Pry up the filter tabs to form a filter frame and install the air filter cartridge. Insulate the ductwork, especially if it’s running through an uninsulated space.

Step 4 - Install Drain Lines

You will most likely use two drain pans to remove condensate from the air handler. Slide them into their appropriate slots. Install a trap close to the drain pan to prevent the air handler from drawing air up through the drain line. Plumb the drain pans to a drain or outside the building. If installing the air handler over a finished space, drain the auxiliary pan to a highly visible area as a warning that the primary drain is clogged.

Step 5 - Run Refrigerant Lines

Do not vent refrigerant into the atmosphere. Use clean and dehydrated copper refrigerant line to connect the evaporator and condenser coils. Move rubber grommets away from this side of the joint while brazing to prevent burning them. Braze the lines together according to the manufacturer’s specifications.

Step 6 - Electrical Wiring

man working on wiring in an air conditioner

For 240-volt connections, disconnect the power source. Open the electrical access panel. Route the supply wire to the electrical box and join the lines with a wire nut. Connect the ground wire to the appropriate terminal. If a 208-volt conversion is required, connect transformer leads. Units with electrical heating elements may have to be connected to the circuit breaker box. Determine how many circuits to reserve for the unit and remove the same number of electrical punch-outs to expose the appropriate terminals. Wire the air handler to the thermostat according to the manufacturer’s wiring diagram.

Step 7 - Reassemble

Replace all access panel covers and reconnect any ductwork. If installing in an unfinished space, seal around the entry point of the electrical wires, refrigerant tubing, and condensate lines.

Step 8 - Test Equipment

Power the equipment on and test the installation. Maintain the air handler by cleaning and changing filters regularly.