E11

Baxi Air Pressure Switch / Flue Safety Fault

Boiler shows E11, often associated with fan or flue issues, no ignition

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

Blocked or kinked air pressure switch tubing, Faulty Baxi air pressure switch, Flue partially blocked or incorrectly installed, Fan not achieving required speed

How to Fix / Troubleshooting

Safety first: Flue and combustion safety components must not be bypassed.

User checks:

Inspect the external flue terminal for obstructions and clear any debris.
Check for signs of condensate blockage (gurgling, water dripping from boiler casing). If the external condensate pipe is frozen, thaw gently with warm water.
Reset the boiler once and listen for the fan starting.

Professional actions:

An engineer will test the air pressure switch, tubing, and fan performance.
They will also verify the flue integrity and correct installation per Baxi specifications.

Repair Difficulty

Professional Required 5/5

Required Part

Air Pressure Switch

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