Warning: Your Navien boiler has detected a failure in the mixing valve, which could lead to system damage if not addressed.
How to Fix Navien Code E279
Step 1: Check if your boiler is receiving power. If not, reset the power by turning off the breaker for a few minutes and then turning it back on.
Step 2: Inspect the mixing valve for any visible damage or leaks. If you find any, do not attempt to fix it yourself and call a professional immediately.
Step 3: If the problem persists, call a licensed HVAC technician to diagnose and repair the issue.
How to Reset Navien Code E279
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 E279 mean?
The E279 error on your Navien boiler indicates a problem with the mixing valve's open circuit. The mixing valve is responsible for blending the hot water from the boiler with the cold water coming into your home. If it's not opening correctly, your boiler can't provide hot water, and you might notice a lack of hot water or reduced water temperature. This issue is typically caused by a faulty valve or a problem with the wiring or control board connected to it.