What does Ideal F1 mean?

Low water pressure — the system pressure has dropped below the minimum the boiler needs to run.

How do I fix Ideal F1?

Try first: Look at the pressure gauge — if it reads under 1 bar, top it up using the filling loop (the silver braided tap) to about 1.2 bar; If it keeps dropping, you likely have a leak or a tired expansion vessel. If that doesn't clear it, the likely part is Expansion vessel.

Ideal F1 Fault — What It Means & Fix Cost

⚠ This is the likely cause from the code — a Gas Safe registered engineer confirms it on site. If you can smell gas, stop and ring 0800 111 999.

✅ Try these first — they're free

Often clears it without a callout:

Look at the pressure gauge — if it reads under 1 bar, top it up using the filling loop (the silver braided tap) to about 1.2 bar
If it keeps dropping, you likely have a leak or a tired expansion vessel

🔧 If that doesn't fix it

The likely cause is one of these — the engineer confirms which:

Pressure dropped over time
Small leak on the system
Failed expansion vessel

Most likely part: Expansion vessel

⚠ Worth knowing

If topping up only holds for a day or two, the expansion vessel is usually the real cause

Fixed repair price

£190

Part + labour, no surprise callout fee. You only pay if you go ahead.

Book a Gas Safe engineer

You pick from the 3 nearest vetted engineers. Your choice gets first refusal; if they don't take it within a few hours it moves to the next nearest automatically — and we keep you posted.

Other Ideal fault codes

Ideal L2Ignition lockout — five failed attempts to light, so the boi…

Ideal F1 — what it means

✅ Try these first — they're free

🔧 If that doesn't fix it

⚠ Worth knowing

Other Ideal fault codes