Replace a Condenser Fan Motor

Match HP, RPM, rotation (CW/CCW from the shaft end), voltage, frame and shaft diameter + mounting; match the run-cap µF; set the blade depth in the orifice and the correct blade pitch/direction; wire per the diagram; then verify rotation and amp draw against the FLA.

Approx. 75 min

Before you start

•Motor confirmed failed (won't start with a good cap, open/grounded windings, dragging bearings, or overheating on the thermal overload) — and the run capacitor checked, since a bad cap kills motors.
•Replacement motor on hand that matches the nameplate: HP, RPM/speed, rotation direction, voltage, frame size, shaft diameter, and mount (stud/belly-band).
•Matching run capacitor (µF + voltage) — a new motor usually wants the µF printed on ITS label, not necessarily the old one.

Tools & materials

Multimeter (ohms/capacitance) + clamp meter · Nut drivers/wrenches, hex keys for the blade set screw · Replacement motor + matched run capacitor · Phone camera (photo wiring before) · Tape measure / scale for blade depth

View

0% complete

Isolate & diagnose

Lock out power, verify 0 V, bleed the cap
Pull the disconnect, verify 0 V, and discharge the run capacitor before touching the motor leads.
Tools: Multimeter
⚠ Lockout/tagout and verify 0 V; bleed the capacitor — it holds a shock.
Read the old motor nameplate
Record HP, RPM, rotation (CW or CCW as viewed from the SHAFT/lead end — be exact, this is the #1 mismatch), voltage, FLA, frame, shaft diameter, and the rotation/cap data. Photo the wiring.
Target: Match HP, RPM, rotation (from shaft end), V, frame, shaft Ø, mount

Remove & mount

Remove the blade, then the motor
Loosen the blade set screw and pull the fan blade off the shaft (note which way it faces). Unbolt the motor from the top grille/bracket and disconnect the leads.
Tools: Hex keys, Nut drivers
Mount the new motor and fit the blade
Mount the new motor in the correct orientation (shaft down on a top-discharge unit so it doesn't take on water; weep hole down). Reinstall the SAME blade facing the SAME direction — a blade flipped or a wrong-pitch blade moves little/no air or runs backward.
Target: Shaft/weep-hole oriented for water shedding; original blade, original facing/pitch

Set blade depth, wire & verify

Set the blade depth in the venturi/orifice
Position the blade so it sits at the correct depth within the fan orifice (typically the blade roughly centered/just below flush in the venturi per the maker) before tightening the set screw on the shaft flat. Too high or too deep loses airflow and raises head pressure.
Target: Blade set to maker's depth in the orifice; set screw on the shaft flat, tight
Wire per the diagram and match the capacitor
Land the motor leads per its wiring diagram (line + the cap lead to FAN on a dual-run), and use the µF/voltage the NEW motor specifies. Cap the unused leads if it has multiple speeds.
Tools: Replacement run capacitor
Target: Wired per diagram; run cap = new motor's specified µF, VAC ≥ rated
Verify rotation and amp draw
Energize on a call, confirm the fan spins the correct direction and pulls air UP/out (top-discharge), and clamp the amps against the motor FLA. High amps = wrong blade/depth, restriction, or wrong motor.
Tools: Clamp meter
Target: Correct rotation + airflow; running amps ≤ nameplate FLA