What does the Navien E785 fault code mean?

Your boiler is struggling to detect the water flow or pressure levels, which is likely preventing it from starting up properly.

How much does it cost to fix Navien error code E785?

Typical repair cost for the Navien E785 fault is £180-350 including labour.

Flow Sensor/Pressure Sensor Error

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Almost always a stuck diverter valve on combis.

Six most common causes of dropping pressure.

7 signs repair isn't worth it anymore.