Boiler displays E020 and stops, often with no circulation in the system
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power and allow the boiler to cool. Close isolation valves before removing any pump components.
- Step 1 – Listen for pump: Call for heat and listen for the internal pump. If silent, check the electrical connector at the pump and PCB.
- Step 2 – Bleed air from pump: Some pumps have a bleed screw. With power off and a towel ready, loosen the screw slightly to release trapped air, then retighten.
- Step 3 – Check for blockage: If accessible, remove the pump head and inspect the impeller for debris or scale. Clean and reassemble with a new gasket if needed.
- Step 4 – Replace pump if seized: If the impeller does not turn freely by hand, replace the pump assembly with a Navien‑approved unit.
If the pump tests good but E020 persists, the PCB pump relay or control logic may be faulty and should be diagnosed by a technician.
Repair Difficulty
Required Part
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