Boiler is very noisy with gurgling sounds in pipes and radiators.

Safety: Use caution when bleeding hot radiators; wear gloves.

• 1. Check system pressure: Ensure pressure is within the recommended range. Low pressure can draw air into the system.
• 2. Bleed radiators: Starting with the highest radiators, use a bleed key to release trapped air until water flows steadily.
• 3. Inspect automatic air vents: Check vents near the Noritz boiler and high points for leaks or stuck caps. Replace faulty vents.
• 4. Repeat as needed: After bleeding, recheck pressure and top up if necessary. Multiple cycles may be needed after a major refill.