BoilerFaultCodesIdeal 0Y Fault Code
The Ideal 0Y fault code means: your boiler has paused briefly because the water inside has reached its maximum set temperature and is waiting for it to cool down before firing up again.. It appears on 1 Ideal model in our database.
Technical description: Water temperature higher than adjusted, unit is waiting
What causes the Ideal 0Y fault?
This occurs when the water heat inside the boiler reaches its target temperature faster than it can be circulated away to your radiators or taps. The boiler pauses its burner briefly to prevent overheating, waiting for the water temperature to drop slightly before it resumes heating. It is often caused by the thermostat being set high or the pump moving water slowly through the system.
This status is more common during the autumn and spring when your heating is on but the weather is mild, meaning your rooms reach their target temperature quickly.
DIY fix possible
Check that your radiator valves are open to allow heat to escape the boilerEnsure your room thermostat is set high enough to call for heatWait up to 5 minutes for the code to clear automatically as temperatures drop
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Gas Safe Register →Ideal models that show the 0Y fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 0Y fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026