BoilerFaultCodesIdeal OVERHEAT FAULT Fault Code
Also written as OVERHEATFAULT — same fault.
The Ideal OVERHEAT FAULT fault code means: your boiler has become too hot and has automatically shut down to prevent damage to the internal components.. It appears on 2 Ideal models in our database.
Technical description: Check system. Replace o/h stat. Press O/H reset button.
What causes the Ideal OVERHEAT FAULT fault?
This fault occurs when the water temperature inside the boiler exceeds a safe limit, causing the safety sensors to shut the unit down to prevent damage. The most common reasons include a failing system pump that isn't moving water away from the heat exchanger fast enough or a buildup of sludge and debris that has restricted the flow of water.
This fault often occurs during the first few cold days of autumn when a heating system that has been dormant all summer is suddenly forced to work at high capacity.
DIY fix possible
Locate the overheat reset button under the control box flapPress the button firmly to reset the safety thermostatCheck that all radiator valves are open and the system pressure is correct
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the OVERHEAT FAULT fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal OVERHEAT FAULT 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