501 High

Atag 501 Fault Code

The Atag 501 fault code means: your boiler is failing to light properly, meaning it cannot produce heat or hot water because the burner is not firing up.. It appears on 2 Atag models in our database.

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.

Technical description: No flame detected
Typical repair cost £100-£350 (including labour)

DIY fix possible

Check that your gas pre-payment meter is in creditEnsure other gas appliances in your home are working to confirm gas supplyReset the boiler by pressing the reset button for 2-3 seconds

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

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Atag models that show the 501 fault code

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

Source

Atag 501 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 7 July 2026