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error Honeywell
Error Code E42
Router is not issuing an IP address to the thermostat. The thermostat cannot obtain network configuration from the router.
? What Causes This
Router not configured to automatically assign IP addresses, or connection timeout.
✓ How to Fix It
- Wait for 30 minutes as connection can take several minutes.
- If still no connection, remove thermostat from wallplate for 10 seconds, then reconnect it.
- Verify your router is correctly set up to automatically give IP addresses.
Source: page 62 of the official manual
From the manual
This error code appears in:
Honeywell RTH6580WF Wi-Fi Smart Thermostat