How much does it cost to fix Atag error code flashing FILL / HIGH?

Cost varies. Contact a Gas Safe registered engineer for a quote.

flashing FILL / HIGH High

Atag flashing FILL / HIGH Fault Code

Q: What does the Atag flashing FILL / HIGH fault code mean?

Your boiler's water pressure has dropped too low, which is preventing it from working at its full heating capacity.

Q: Can I fix Atag fault code flashing FILL / HIGH myself?

Locate the external filling loop, which is a silver braided hose connecting two pipes near your boiler.

Also written as FLASHINGFILLHIGH — same fault.

The Atag flashing FILL / HIGH fault code means: your boiler's water pressure has dropped too low, which is preventing it from working at its full heating capacity.. It appears on 1 Atag model in our database.

Technical description: 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.

DIY fix possible

Locate the external filling loop, which is a silver braided hose connecting two pipes near your boiler.Open the valves at both ends of the hose slowly to allow water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches 1.5 bar, then turn both valves firmly off.

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Atag models that show the flashing FILL / HIGH fault code

Click a model for the full fault code list and model-specific repair notes.

E Range

Source

Atag flashing FILL / HIGH fault code information on this page is sourced and cross-checked against the official Atag service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026