Medium
FILL (flashing) on Atag Q 25CR

Your boiler's water pressure has dropped too low, so it needs you to top it up using the external filling loop before it can work at full capacity.

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 (<1,0 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 Boiler Ata 012 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 filling loop (a flexible metal hose) connected between two pipes under your boiler.Open the valves on both ends of the hose slowly to allow water into the system.Watch the pressure gauge on the boiler until it reaches 1.5 bar, then turn the valves off tightly.

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