Warning: Your Navien tankless water heater has detected a problem with its mixing valve and has shut down to prevent potential issues. You'll need to troubleshoot or call a technician to restore hot water.
How to Fix Navien Code E445
Step 1: Power cycle the unit. Turn off the power to the Navien at the breaker for 30 seconds, then turn it back on. This may clear a temporary glitch.
Step 2: Check the water pressure. Ensure that both the hot and cold water supply pressures are within the recommended range for your Navien model (typically 20-80 PSI). Low pressure can affect the mixing valve's operation.
Step 3: If the error persists after these steps, contact a qualified HVAC technician to diagnose and repair the issue.
How to Reset Navien Code E445
Turn off the unit using the power button on the front panel.
Turn off the gas supply valve.
Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
Restore power at the breaker, then open the gas valve.
Turn the unit back on. If the error returns, the underlying issue needs repair.
What does E445 mean?
The E445 error code on your Navien tankless water heater indicates an issue with the mixing valve. This valve is responsible for blending hot and cold water to achieve your desired output temperature. When the system detects an abnormal condition within the mixing valve's operation, such as a failure to reach the target temperature or erratic behavior, it triggers the E445 error and shuts down the unit as a safety measure. This prevents you from getting scalding hot water or, conversely, no hot water at all. It's important to address this promptly to restore consistent hot water supply and prevent potential damage to other components.