How much does it cost to fix Atag error code 30?

Typical repair cost for the Atag 30 fault is £120-£350 including labour.

30 High

Atag 30 Fault Code

Q: What does the Atag 30 fault code mean?

Your boiler has detected that water is not circulating through the system properly, causing a large temperature gap between the water leaving and returning to the unit.

The Atag 30 fault code means: your boiler has detected that water is not circulating through the system properly, causing a large temperature gap between the water leaving and returning to the unit.. It appears on 1 Atag model in our database.

Technical description: Difference between flow and return temperature too high

Typical repair cost £120-£350 (including labour)

DIY fix possible

Check that all radiator valves and boiler isolation valves are fully open.Ensure the system pressure is between 1.0 and 1.5 bar on the pressure gauge.Bleed all radiators to remove trapped air that might be blocking water flow.Restart the boiler by pressing the reset button.

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Atag models that show the 30 fault code

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

E Range Repair: £120-£350

Source

Atag 30 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