Medium
E33 on Chaffoteaux Minima HE

Your boiler has detected that the external temperature sensor for your underfloor heating system is not sending a signal, which is preventing the boiler from firing.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Floor heating thermostat open circuit (if fitted)

From this model's manual
Verified against the Chaffoteaux Minima He installation & service manual, page 51.
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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