Ecobee ecobee SmartThermostat with Voice Control and Alexa Built-In FAN-CONSTANT Error Fix: Fan Running Constantly

Error code FAN-CONSTANT on the Ecobee ecobee SmartThermostat with Voice Control and Alexa Built-In means: Fan Running Constantly. The HVAC fan runs nonstop even when not calling for heating or cooling — check that the fan setting is set to Auto (not On) in the thermostat, verify the G-wire (fan) connection, and check if a stuck fan relay on the HVAC control board is keeping the fan energized

The most successful fix is "Test and Replace HVAC Control Board Fan Relay" (hard difficulty, ~60 minutes). Estimated DIY cost: $10-$20. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Test and Replace HVAC Control Board Fan Relay") is rated hard difficulty and takes about 60 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

DIY cost: $10-$20. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

The Ecobee ecobee SmartThermostat with Voice Control and Alexa Built-In has 8 other known error codes, including: APP-SYNC (App and Thermostat Out of Sync), AUX-OUTDOOR (Auxiliary Heat Outdoor Temperature Alert), AUX-RUNTIME (Auxiliary Heat Runtime Alert), BLOWN-FUSE (HVAC Control Board Fuse Blown), COOL-FAIL (Cool Not Reaching Set Temperature), and 3 more.

Error code FAN-CONSTANT also appears on 5 other Ecobee models: ecobee Smart Thermostat Enhanced with Radar Occupancy Sensor and Large Touchscreen, ecobee Smart Thermostat Essential with Touchscreen Display and eco+ Smart Features, ecobee Smart Thermostat Premium with Siri and Alexa Built-In, Air Quality Monitor, and SmartSensor Included, ecobee3 Lite Smart Thermostat, ecobee4 Smart Thermostat. The fix may vary by model, so check each model's specific page for tailored repair steps.