F6 on an Ideal boiler is an outside sensor fault. The external sensor used for weather compensation is not giving a usable reading.

This is one of the least disruptive codes on the list. In most cases the boiler carries on heating, just without weather compensation.

What F6 actually means

Weather compensation uses an outdoor sensor to adjust the flow temperature to the weather, which makes the system more efficient and more comfortable.

If that sensor fails, the boiler loses the compensation function. It flags the fault so you know the efficiency benefit has gone.

What you can safely check yourself

If you know where the outdoor sensor is, usually on a north facing external wall, check it has not been knocked, damaged or painted over.

Beyond a visual look, the wiring and the sensor itself need testing.

When to stop, and why

What causes it beyond the simple checks

A failed sensor, damaged or water ingressed wiring between the sensor and the boiler, a poor connection at the terminal, or a PCB input fault. Outdoor sensors live outside, so weather related failure is common.

How Vantage can help

We are Gas Safe registered under 956889 and cover Hertfordshire, Bedfordshire and Cambridgeshire, with an emergency line answered 24 hours a day. Call us on 01462 506374. See also boiler repair and boiler servicing.

Frequently asked questions

Will my heating still work with F6?

Usually yes. You lose weather compensation, which means slightly higher running costs, but the boiler generally keeps heating.

Is it worth fixing?

If you paid for weather compensation, yes. It is a real efficiency feature and the sensor is not expensive.

Could it just be the wiring?

Frequently, given the sensor is outdoors. That gets checked before the sensor is replaced.

Related fault codes

Other Ideal codes: L1 · L2 · LC · L6 · F1 · F2 · F3 · F4 · F5 · F7 · F8 · F9 · all boiler advice. See also boiler repair.

In Ideal’s own words

Ideal use different code sets across their ranges and generations. The definition above comes from The Ideal installation and servicing guide. If your boiler is a different model and the code behaves differently, check the manual for your appliance or ring us and we will tell you what it means on your unit.

When to call an engineer

If the checks above have not cleared it, the next steps are engineer work and the boiler should not be reset repeatedly in the meantime. Call Vantage Plumbing and Heating on 01462 506374. We are Gas Safe registered under 956889, the line is answered by a person at any hour of any day, and you get a price before anyone starts.

Need help today?

Call and speak to a person, any hour, any day of the year. Get a fixed price quote or call 01462 506374.