Noritz water heater frequently shuts off when multiple fixtures are used simultaneously; water goes cold until some fixtures are closed.

Safety first: None beyond normal caution; this is typically a sizing issue, not an immediate hazard.

Steps to check and correct:

• Reduce simultaneous demand: Stagger hot water usage (e.g., avoid running multiple showers and appliances at once).
• Lower set temperature: Reducing the setpoint (e.g., from 140°F to 120°F) can increase usable flow.
• Check gas line sizing: Have a technician verify that the gas line and meter are sized for the heater's maximum BTU input.
• Consider additional capacity: If demand regularly exceeds capacity, consult a Noritz installer about adding a second unit in cascade or upgrading to a higher-capacity model.