Furnace shows E7 and shuts down, indicating a fan or blower fault

Safety first: Turn off power and wait for all moving parts to stop. Do not bypass blower safeties.

Steps:

• Inspect blower compartment: Remove the blower access panel. Check that the blower wheel spins freely by hand. Remove any debris or insulation that may be obstructing the wheel.
• Check motor wiring: Inspect the multi-pin connector on the ECM blower motor and the harness back to the Danfoss control. Reseat connectors and look for damaged insulation.
• Listen for motor start: With panels replaced and power restored, call for heat and listen for the blower start command. A humming motor that does not turn suggests a seized motor or failed capacitor (for PSC motors).
• Clean speed sensor (if external): Some systems use an external Hall sensor on the blower shaft. Gently clean dust from the sensor and ensure the gap to the magnet is correct.
• Reset and test: Clear the E7 error and run a cycle. If the blower still fails to start or the error returns, the motor or control electronics likely need replacement.