304 error code
ATAG 304 error code – Too many resets
What does ATAG ATAG iC, iS and iR boiler range — 2019 and newer 304 mean?
ATAG identifies code 304 as: Too many resets.
The code identifies the condition detected by the product; it does not always identify the failed component on its own. Confirm the full code and exact model before ordering parts or attempting a reset.
The ATAG ATAG iC, iS and iR boiler range — 2019 and newer 304 error code indicates aTAG identifies code 304 as: Too many resets. This guide explains what the code means, the symptoms and likely causes, the checks that are safe to make, and when to stop and arrange an authorised repair.
Symptoms you may notice
The boiler has detected the stated operating fault and may restrict or stop operation.
Common causes
The exact cause depends on the boiler model, installation and operating conditions.
Before you start troubleshooting
Use the display, rating label or product menu to confirm the exact model. Similar-looking codes can have different meanings across product generations and regions.
- Record the complete code before switching the equipment off.
- Check only user-accessible controls, filters and external connections described in the manual.
- Do not open gas, refrigerant, combustion or electrical compartments.
Troubleshooting steps
Record the complete code and model, check only user-accessible items, and use the official ATAG guidance before attempting a reset.
Can you fix this error code yourself?
The safest next step depends on the exact model and the cause behind the code. External checks may help, but a returning fault needs professional diagnosis.
A successful reset is not proof that the underlying issue is fixed. If 304 reappears, note when it happens and give that information to the service engineer.
Reset instructions
Reset a locked boiler only as described in the ATAG user manual and only after safe external checks. Temporary blocking codes may clear automatically. Do not repeatedly reset a returning fault.
Applicable products and models
ATAG iC, iS and iR boiler range — 2019 and neweriC; iS; iR; iC Economiser2019 onwardWhen to contact a professional
Contact ATAG or a Gas Safe registered engineer when the code persists, the boiler locks again, pressure will not remain stable, or internal component testing is required.
Frequently asked questions
What does ATAG ATAG iC, iS and iR boiler range — 2019 and newer 304 mean?
ATAG identifies code 304 as: Too many resets.
Can I fix ATAG ATAG iC, iS and iR boiler range — 2019 and newer 304 myself?
Some external checks may be suitable for the user, but the result depends on the exact model and cause. Use the official manual and arrange service if the code returns.
Should I reset the product after code 304?
Reset a locked boiler only as described in the ATAG user manual and only after safe external checks. Temporary blocking codes may clear automatically. Do not repeatedly reset a returning fault.
When should I arrange a repair?
Contact ATAG or a Gas Safe registered engineer when the code persists, the boiler locks again, pressure will not remain stable, or internal component testing is required.