High
LED 2 yellow (0) [DHW mode] on Ferroli Arena

Your boiler does not realise that you have turned on your hot water tap, so it is failing to heat the water for your shower or kitchen faucet.

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

D.H.W. flow switch (38) not operating.

From this model's manual
Verified against the Ferroli Boiler Optima 201 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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