Boiler display shows E12, indicating intermittent operation, which may coincide with power issues.

Safety: Only work on line-voltage wiring if you are qualified. Turn off power at the breaker and verify that it is off.

Steps:

• 1. Verify dedicated circuit: The boiler should be on its own properly sized circuit. Avoid sharing it with large motors (well pumps, compressors) that cause voltage dips.
• 2. Tighten connections: Inspect the junction box on the boiler. Tighten wire nuts and terminal screws for hot, neutral, and ground connections.
• 3. Check breaker and wiring: Look for signs of overheating or discoloration at the breaker and receptacle (if used). Replace damaged components.

Professional service: An electrician or technician should measure voltage and frequency under load and replace the control board if its internal power supply is faulty.