BoilerFaultCodesIdeal UF Fault Code
The Ideal UF fault code means: your boiler is currently in a manual testing or service mode used by engineers and is not actually reporting a breakage or fault.. It appears on 6 Ideal models in our database.
Technical description: Service Mode / Sequence indicator following SH
What causes the Ideal UF fault?
This code appears when the boiler has been manually put into a specific testing mode, typically by an engineer during a service or installation. It indicates that the system is running at a fixed rate to check performance rather than responding to your thermostat. It is not caused by a mechanical failure, but rather by the control dial being left in a certain position or a button sequence being activated.
DIY fix possible
Wait 5 to 15 minutes for the boiler to automatically exit the service modeRotate the main mode dial back to the 'Off' position and then back to 'On/Winter'Press the 'Reset' button once to clear the display
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like UF: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Ideal models that show the UF fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal UF 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 31 August 2026