High
N.270 on Vaillant ecoTEC plus Combi

Your boiler has detected that hot water is not transferring correctly through its internal heating system, so it is limiting its own performance to prevent further stress.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

The temperature spread via the secondary heat exchanger (heating flow – domestic hot water connection) is too high. The unit switches from regulating to controlling until the cause has been eliminated by customer service.

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 94.
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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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