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Honeywell Error Codes
Honeywell home thermostats and HVAC controls
7 error codesthermostat
Honeywell thermostat Error Codes
E1
Loss of Connection to Equipment — the thermostat has lost communication with the HVAC equipment.
🚨 Critical$50–$400
E2
Indoor Sensor Failure — the indoor air temperature sensor has failed.
⚠️ Warning$80–$300 for new thermostat
E3
Outdoor Sensor Failure — the outdoor temperature sensor has failed or disconnected.
ℹ️ Info$30–$100 for outdoor sensor
Cool On Flashing
Compressor Delay Protection — the thermostat is waiting before allowing the AC compressor to start to prevent short cycling.
ℹ️ Info$0 (normal delay) to $200+ for AC service
ERR
General sensor error — an internal sensor has returned an out-of-range value.
⚠️ Warning$150–$250 thermostat replacement
Recovery
Smart recovery mode — thermostat started heating/cooling early to reach target temp by scheduled time.
ℹ️ InfoFree — no repair needed
Blank Screen
Thermostat Has No Power — the display is blank and the unit is not functioning.
🚨 Critical$5 (batteries) to $150 (thermostat replacement)
Related Troubleshooting Guides
Guide
Refrigerator and Thermostat Error Guide
Troubleshooting guidance for cooling, open-door, sensor, and HVAC control related error messages.
Guide
E1 first steps guide
The first checks to make when you see error code E1.
Guide
E1 meaning and causes guide
A clearer explanation of what E1 usually means and what tends to cause it.