Medium
FILL on Atag Q 25S

Your boiler has lost water pressure and needs a simple top-up to return to full working order.

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

Water pressure is to low (<0,7 bar), flashing FILL will alternate with indication of water pressure, boiler power of 50% is possible. The installation needs to be topped up.

From this model's manual
Verified against the Atag Q 25s 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.

DIY fix possible

Locate the external filling loop, which is a flexible braided hose usually found underneath the boiler.Open the valves at both ends of the hose until you hear water entering the system.Watch the pressure gauge on the front of the boiler and close the valves once the needle reaches 1.5 bar.

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