Boiler shuts down and displays error 14 after running for a short period.

Safety: Turn OFF power and close the water and gas valves before servicing. Surfaces may be hot.

• 1. Check system water flow: Ensure all isolation valves around the Noritz boiler are fully open. Confirm that system pumps are running and that zone valves are open when there is a call for heat.
• 2. Clean inlet water filter: Shut off cold water to the boiler. Remove and clean the inlet water filter screen (usually at the cold water inlet). Rinse debris and reinstall.
• 3. Inspect for scale: If the boiler is in a hard-water area and has not been descaled, internal scale may be causing localized overheating. Plan a full heat exchanger descaling using a pump, hoses, and approved descaling solution per Noritz instructions.
• 4. Check for restricted piping: Look for closed valves, kinked flexible hoses, or clogged strainers in the boiler loop.
• 5. Professional service: If error 14 recurs after restoring flow and cleaning filters, the thermal fuse or overheat sensor may be damaged and must be replaced by a qualified technician.