Boiler displays E10; may indicate outdoor sensor fault on weather-compensated Crown models

Safety: Turn off power before working on wiring.

• Locate outdoor sensor: Find the small sensor housing mounted on an exterior north or northwest wall. Inspect for physical damage or water intrusion.
• Check wiring: Follow the low-voltage cable back to the boiler. Look for cuts, staples through the cable, or loose connections at the Crown control board terminals.
• Verify connections: Tighten the terminal screws and ensure polarity matches the installation manual (if applicable).
• Bypass (temporary test only): A technician may temporarily substitute a known-good resistor to simulate a normal temperature for testing. Homeowners should not modify sensor circuits.
• Reset: Restore power and reset the boiler. If E10 persists, replace the outdoor sensor with a Crown-approved part.