What it means
Ideal's Logic Code Combi ESP1 page calls it Low Mains Voltage.
What to do
- Have the electrics checked
Ideal recommends contacting a qualified electrician or your electricity provider.
When to call a Gas Safe engineer
Ideal points you to an electrician or your electricity provider rather than a gas engineer.
A repair visit will usually check the supply at the socket, the plug and the machine's power input.
- Note the model and serial number. They're on a label on the data badge, usually under the boiler or behind the front cover.
- Write down the exact code, and what the appliance was doing when it appeared.
- Check whether it's still under warranty. If it is, the repair may cost you nothing.
Quick answers
What does the Ideal F7 fault code mean?
The boiler isn't getting enough voltage from your electricity supply. It's a problem with the electrics, not the gas. Ideal's Logic Code Combi ESP1 page calls it Low Mains Voltage.
Can I fix Ideal F7 myself?
Engineer only (electrician visit). Start with: have the electrics checked. Ideal points you to an electrician or your electricity provider rather than a gas engineer.
Is Ideal F7 worth repairing?
Get a quote first. The boiler itself is probably fine. Get an electrician to check the supply.
Checked against
- Ideal Heating: Logic Code Combi ESP1 troubleshooting manual
- Ideal Heating: what does my boiler fault code mean
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.