Noritz water heater makes loud banging or popping noises during operation.

Safety first: Turn OFF power and gas. Allow the unit to cool before connecting hoses.

Steps to check and correct:

• Perform descaling: Connect a pump and hoses to the Noritz service valves and circulate white vinegar or approved descaling solution through the heat exchanger for 45–60 minutes, following the Noritz service instructions.
• Flush thoroughly: After descaling, flush with clean water to remove residual solution.
• Install water treatment: In hard water areas, consider a water softener or scale reduction system upstream of the heater.
• Adjust temperature: Lower the set temperature if it is unnecessarily high to reduce future scale formation.