BoilerFaultCodesIdeal SH Fault Code
The Ideal SH fault code means: your boiler is currently in service mode, which is an intentional setting used by engineers to test the system and not a mechanical breakdown.. It appears on 5 Ideal models in our database.
Technical description: Service Mode / Sequence indicator following SL
What causes the Ideal SH fault?
This code appears because the boiler has been manually placed into a high or low fire test mode, typically by an engineer during an annual service or safety check. It is not a mechanical failure, but rather a temporary override that allows a technician to measure gas pressures and performance. Once the technician finishes their tests or exits the menu, the boiler will return to its normal heating settings.
This code is more frequent during the summer or autumn months when homeowners typically book their annual boiler service or gas safety record inspections.
DIY fix possible
Locate the mode dial on the front of the boiler control panel.Turn the dial away from the 'Service' or 'Spanner' icon back to 'Auto', 'On', or your desired temperature setting.Restart the boiler by pressing the reset button if the display does not clear immediately.
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Gas Safe Register →Ideal models that show the SH fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal SH 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