Replace a Draft Inducer Motor (Furnace)

Confirm the inducer is the fault, swap it with a NEW gasket, clear the pressure-switch port and sensing tubing while you're in there, then verify the pressure switch closes on inducer start, the wheel spins free, and amp draw is on-spec.

Approx. 75 min

Before you start

•Inducer confirmed failed: won't start (open winding/bad cap), noisy/dragging bearings, a cracked/loose wheel, or it runs but can't pull enough draft to close the pressure switch.
•Replacement inducer assembly that matches the OEM part (voltage, CFM/draft rating, mounting, and rotation), and a NEW mounting gasket.
•Power can be killed at the furnace switch/breaker and a meter is available for amp draw and the pressure switch.

Tools & materials

Multimeter + clamp meter · Nut drivers/screwdrivers · Replacement inducer + new gasket · Shop vac / tube brush to clear the pressure port

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Isolate & remove

Kill power, verify 0 V
Turn off the furnace switch and breaker and verify 0 V at the inducer leads. Note the pressure-switch tubing routing before disturbing it.
Tools: Multimeter
⚠ Verify 0 V before disconnecting the inducer leads.
Remove the old inducer
Disconnect the leads and pressure tubing, remove the mounting screws, and pull the inducer off the flue collector. The old gasket usually tears — plan to replace it.
Target: Note tubing routing + gasket position before removal

Install with a new gasket

Mount the new inducer with a NEW gasket
Always install a new gasket between the inducer and the collector box — a reused/torn gasket leaks flue gas and a leak there can spill CO and prevent the pressure switch from holding. Seat it square and snug the screws evenly.
Target: New gasket, square seat, evenly torqued
⚠ Use a NEW gasket — a leaking inducer-to-collector seal can spill combustion gas/CO.
Clear the pressure-switch port and tubing
While it's apart, clear the pressure-switch sensing port on the inducer housing and the tubing of soot/condensate. A plugged port is a classic 'won't fire / pressure switch open' fault even with a good inducer.
Tools: Tube brush, Shop vac
Target: Sensing port + tubing clear and dry; reconnect to the correct port

Verify draft & operation

Confirm the pressure switch closes on start
Restore power, call for heat, and confirm the inducer starts AND the pressure switch closes (meter across the switch, or watch the sequence proceed to ignition). If it won't close, recheck the port, tubing, vent, and that the inducer is pulling rated draft.
Tools: Multimeter
Target: Pressure switch closes shortly after inducer start; sequence advances
Check amp draw and a free wheel
Clamp the inducer amps against the nameplate and confirm the wheel coasts freely (no rub/drag). High amps or a rub means a misseated wheel, debris, or the wrong assembly.
Tools: Clamp meter
Target: Running amps ≤ nameplate; wheel spins free, no rub