Navien Error Code E445: Abnormal Mixing Valve
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.
What Does Navien Error Code 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.
Common Causes of Navien Code E445
- Mixing valve failure: The valve itself may be faulty due to wear and tear, scale buildup, or internal component failure.
- Faulty mixing valve actuator: The actuator motor that controls the valve's position may be malfunctioning.
- Wiring or connection issues: Loose or damaged wiring between the mixing valve and the main control board can cause communication problems.
- Software Glitch: A rare software glitch in the Navien's control board could cause a false error reading.
Applicable Navien Models
Source Documentation
This error code is documented in 2 official Navien technical manuals.
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