!!
critical Honeywell
Error Code E3
System error — a general system malfunction has been detected.
? What Causes This
Internal thermostat failure, software error, or hardware malfunction.
✓ How to Fix It
- Power off the thermostat by switching the breaker off.
- Wait 30 seconds and power back on.
- If error persists, reset to factory settings via Menu > SETTINGS > RESET.
- If still present, contact Honeywell support.