Low
P11 on Vaillant Thermocompact

Your boiler is currently performing a factory calibration check to ensure the gas and air balance is set correctly for your home's fuel supply.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Mid setting point for natural gas (G20)

From this model's manual
Verified against the Vaillant Turbomax Plus 824 828e installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

P12View →P13View →

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