High
Radiators cold in winter on Ferroli Sigma 40 FF

Your boiler is struggling to push warmth around your home because the internal parts responsible for moving or measuring hot water are not working as they should.

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

Faulty flow temperature sensor. Room thermostat set too low or faulty. Pump is stuck and fails to rotate. The pump does not rotate

From this model's manual
Verified against the Ferroli Sigma 40 Ff 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 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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