High
F42 on ECA Confeo Premix HST

Your boiler is unable to top itself up with water because the filling process has timed out, likely due to low mains pressure or a part becoming stuck.

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

Water Filling (Auto) Not Completed (blocking) — water filling valve may have failed or mains water pressure insufficient; notify ECA authorised service

From this model's manual
Verified against the Eca Confeo Premix Hm installation & service manual, page 43.
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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Related fault codes

F40View →F41View →

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