E20

Baxi Circulation Fault / Pump Error

Boiler shows E20, often associated with pump or circulation problems

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

Seized or failed Baxi pump, Airlock in primary circuit, Blocked system filter or sludge in pipework, Closed isolation valves on flow/return

How to Fix / Troubleshooting

Safety first: Allow the boiler and system to cool before touching any pipework.

User checks:

Check that flow and return isolation valves under the boiler are fully open.
Verify system pressure is correct (1.0–1.5 bar cold) and top up if needed.
Bleed radiators to remove air and then re-pressurise.
Listen when the boiler starts: you should hear the pump running with a gentle hum, not loud grinding or silence.

Professional actions:

An engineer can remove the pump head to free a stuck rotor, check for debris, or replace the pump assembly.
They may also clean or fit a magnetic system filter and flush sludge from the system.

Repair Difficulty

Hard 4/5

Required Part

Circulation Pump

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