Noritz Error Code 65: Main Flow Control Valve Abnormality

How to Fix Noritz Code 65

1. Check if the error code is still displayed after turning the unit off and then back on again
2. If the code persists, turn off the water heater and contact a licensed HVAC technician for repair
3. Do not attempt to open the unit or repair the flow control valve yourself, as this can void the warranty and may cause safety hazards

How to Reset Noritz Code 65

1. Turn off the unit using the power button on the front panel.
2. Turn off the gas supply valve.
3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
4. Restore power at the breaker, then open the gas valve.
5. Turn the unit back on. If the error returns, the underlying issue needs repair.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Noritz Error Code 65 Mean?

The Noritz 65 error code indicates an abnormality with the main flow control valve in your tankless water heater. This valve regulates the flow of water through the system. When it's not working properly, your water heater may not function as efficiently as it should. The error code is displayed on the control panel, and the unit will operate at a reduced capacity until the issue is resolved.

Common Causes

• Wiring or electrical issues related to the flow control valve
• Malfunctioning flow control valve itself
• Clogging or scaling in the valve due to hard water or lack of maintenance
• Incorrect water pressure settings

Diagnostic Steps

Replacement Parts

Related Codes on Same Models

Other codes that affect the same Noritz model families as 65.