F7 High

Ideal F7 Fault Code

The Ideal F7 fault code means: your boiler has stopped working because the electricity supply coming into your home is currently too weak to power the internal electronics safely.. It appears on 17 Ideal models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Low mains voltage – contact electricity provider.

What causes the Ideal F7 fault?

This fault occurs when the electrical voltage reaching the boiler drops below the minimum level required for its sensitive electronic components to function. While it can occasionally be caused by a failing internal control board, it is most often the result of an external issue with the local power grid or a temporary 'brownout' in your area. The boiler shuts down as a safety precaution because it cannot guarantee the correct operation of the gas valve and fan at such low power levels.

This fault is slightly more common during winter or extreme hot spells when the national grid is under heavy load, leading to a temporary drop in local supply voltage.

Typical repair cost £0-250 (including labour)

DIY fix possible

Check if other appliances or lights in your home are flickering or dimmingSwitch the boiler off and back on at the fused spur switch to see if the error clearsContact your regional electricity distribution network operator (DNO) to report a local supply issue

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Ideal models that show the F7 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal F7 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