BoilerFaultCodesIdeal 0H Fault Code
The Ideal 0H fault code means: your boiler is working perfectly and is currently sitting in standby mode because it has already reached the required temperature.. It appears on 1 Ideal model in our database.
Technical description: Unit is stand-by; no heat required
What causes the Ideal 0H fault?
This code appears when the boiler has successfully heated the water to the temperature set on your thermostat and has temporarily switched off to save energy. It is a normal part of the boiler's cycle, indicating that it is simply waiting for the temperature to drop or for a new request for heat before firing up again. There is no actual fault with the system; it is just resting in standby mode.
This status is most frequently seen during spring and autumn when the weather is milder and your home retains heat for longer periods between cycles.
DIY fix possible
Check if your room thermostat is turned up high enough to ask for heatEnsure your heating programmer or timer is set to an 'on' periodWait for the temperature to drop; the boiler will start automatically when heat is needed
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Gas Safe Register →Ideal models that show the 0H fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 0H 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