Boiler locks out intermittently during very cold weather without a specific error code.

Safety: Protect the boiler and piping from freezing to avoid burst pipes.

• 1. Check outdoor sensor: If your Noritz boiler uses an outdoor reset sensor, ensure it is properly mounted and wiring is intact.
• 2. Inspect condensate line: Look for frozen sections or ice buildup at the outlet. Thaw gently with warm towels and insulate exposed sections.
• 3. Maintain room temperature: Ensure the boiler room or mechanical space stays above freezing.
• 4. Professional review: A technician can verify freeze protection settings and recommend additional insulation or heat tracing if needed.