Worcester Bosch CE fault codes — what the number means and what to do

What does the Worcester Bosch CE fault mean?

The Worcester Bosch CE fault means your boiler has read a value that's out of range or lost a signal from one of its sensors — it's a sensor, communication or pressure error. The three-digit number that flashes alongside the "CE" is the bit that matters: it tells you exactly which sensor or condition tripped the fault, and whether it's something you can sort yourself or one for a Gas Safe registered engineer.

So "CE" alone isn't enough to act on — you need the number. CE 207, CE 201, CE 224 and the rest are all different faults that happen to share the same "CE" family label. Find your number in the lookup table below and it'll point you straight to what's going on.

Good news first: a CE code is not a gas emergency on its own. The National Gas Emergency line, 0800 111 999, is only for when you can smell gas or your carbon monoxide alarm is going off — not for a CE fault. CE codes can vary by Greenstar model, so it's always worth checking the number against your boiler's manual.

Worcester Bosch CE code lookup

How to read your CE number

Once you know how the code is built, it's simple to decode.

1. The letters tell you the family. CE means a communication, sensor or pressure error — the boiler's control board has read something it doesn't like.

2. The three-digit number tells you the exact fault. That's the bit to match in the lookup table above.

3. If your boiler is newer and shows an E- or F-code instead — like E2, E9 or F7 — look up the same number. A newer display and an older CE display usually mean the same thing for the same number.

4. The fastest no-cost check is the pressure gauge. Anything in the low-pressure family (the CE 207 low-pressure variant, H07, D5) is usually a homeowner fix. Sensor and flame numbers (201, 203, 222, 224, 228) are engineer jobs.

On most newer Greenstar boilers the fault doesn't sit still — it alternates between the "CE" prefix and its number, which is why the number is so easy to miss. Watch the display through a full cycle and write the number down before you do anything else.

CE faults at a glance — the key facts

What can I safely do myself, and when do I call a Gas Safe registered engineer?

This is the most useful split with CE codes, because the answer changes depending on your number. Here's the honest line on each.

The one you can usually fix yourself — CE 207 (low pressure)

If your CE 207 is the low-pressure kind — the pressure gauge is sitting below about 1 bar — you can sort this yourself by topping the system back up. It's the same fix as an H07 or a D5 low-pressure code. The steps are below.

The catch: if the pressure drops again within a few days, don't just keep topping it up. A repeated drop means you've got a small leak somewhere, and that needs finding. Stop topping up and book an engineer to trace it.

The ones that need a Gas Safe registered engineer

Every CE code that points at a sensor or combustion needs a registered engineer — they're not DIY jobs. CE 201, CE 203, the sensor version of CE 207 and CE 222 are all temperature or flow-sensor faults that need proper diagnosis and a replacement part. CE 224 is an overheat / high-limit trip — once water and a single reset don't clear it, it's an engineer job, because something is making the boiler run too hot. CE 228 is a false-flame fault tied to the flame-sensing circuit and the gas valve, so it's strictly Gas Safe only.

The rule that covers all of them: it's illegal for anyone who isn't Gas Safe registered to work on the gas side of a boiler, and opening the casing isn't worth the risk. You can check an engineer is registered on the Gas Safe Register. While you wait, you can book a one-off repair with us and one of our Gas Safe registered engineers will come and fix it for you.

How do I fix a low-pressure CE 207 myself?

If your gauge shows low pressure, re-pressurising is a genuine homeowner job. You don't open the boiler or touch anything to do with gas — you just let a little mains water back into the heating system through the filling loop.

1. Turn the boiler off and let it cool. You'll get a more accurate reading and it's safer to work near.

2. Find the filling loop. It's usually a silver braided hose with a valve at each end under the boiler. Some models have an internal key-operated filling link instead — a little key or lever you turn anticlockwise. Check your manual if you can't see a braided hose.

3. Open both valves slowly. You'll hear water flowing into the system. Watch the pressure gauge as it climbs.

4. Stop at 1.0–1.5 bar — the green zone on most gauges. Close both valves fully. Never push past 1.5 bar; over-pressurising can damage the internal seals.

5. Turn the boiler back on and reset once if the code is still showing. It should fire up and the CE 207 should clear.

If the pressure holds, you're done. If it drops again over the next day or two, you've likely got a leak — book an engineer rather than topping it up over and over.

Safe checks before you call anyone out

The only things worth trying yourself with a CE code. If your number isn't the low-pressure CE 207, the next step is a Gas Safe registered engineer.

• Read the full code. Watch the display cycle and write down the three-digit number after CE — that's the part that decides everything.
• Check the pressure gauge first. It should sit around 1.0 to 1.5 bar when cold. Low pressure points to a CE 207 you can fix yourself.
• If pressure's low, top up via the filling loop to 1.0–1.5 bar, then close the valves fully. Never go past 1.5 bar.
• Reset the boiler once — just once. Don't keep resetting if the code returns, and don't keep resetting an overheat (CE 224).
• If pressure drops again within days, stop topping up — that's a leak for an engineer to trace.
• Never open the casing or touch sensors, the flame circuit, the gas valve or wiring — that's a Gas Safe registered engineer's job.
• If you ever smell gas or your CO alarm sounds, stop. Call 0800 111 999, open windows, turn off the gas at the meter, don't touch electrical switches, and leave the house.

Is a CE fault dangerous?

No — a CE fault isn't dangerous in itself. It's the boiler doing its job: it spotted a reading it couldn't trust, or pressure outside its safe range, and stopped rather than carry on. That fault-out is a safety feature, not a hazard.

It is not a 999 or gas emergency. You only need the National Gas Emergency line, 0800 111 999, if you can smell gas or your carbon monoxide alarm goes off — and that's true whatever code is showing. If that happens, leave the gas alone, open the windows, turn the gas off at the meter, don't touch electrical switches, and get everyone out, then call 0800 111 999.

The one thing not to do is keep resetting it. A code clearing for a few minutes doesn't mean it's fixed — it means the fault hasn't shown itself again yet. Reset once, and if it returns, hand it to an engineer. This matters most with CE 224, an overheat trip, where repeated resetting can add wear to the boiler.

How much does it cost to fix a CE fault?

It depends entirely on the number, so the honest answer is a range. The figures below are typical UK industry costs to give you a feel for it — they are not Smart Plan's prices, and your own quote will depend on your boiler and where you live.

Re-pressurising a low-pressure CE 207 costs nothing if you do it yourself — it's just a few minutes with the filling loop and no parts. If a leak has to be traced and repaired, that's typically £120–£300. A temperature or NTC sensor — the likely fix for CE 201, CE 203, CE 222 and the sensor version of CE 207 — sits in the sensor and controls band, often around £90–£200 fitted once diagnosis and labour are added, even though the part itself is cheap. The dear one is a PCB (control board), typically £180–£400, which is often the "is it worth it?" moment on an older boiler. A standalone diagnostic visit on its own is usually around £75–£120 in the wider trade.

Should you repair or replace the boiler?

A sensor or a re-pressurise is worth doing at almost any age. But if you're looking at a PCB on a boiler that's already 10–15 years old and faulting repeatedly, it's worth getting a view on a replacement. As a rough rule, once a repair creeps toward a third or more of the cost of a new boiler, replacing it often makes more sense than stacking up repairs. A Gas Safe registered engineer can tell you which way to lean.

Smart Plan is a service plan, not insurance. If you'd rather not face a surprise repair bill next time, an ongoing boiler module covers parts and labour up to your cover limit, so a fault like this is sorted for you. Cover is modular — you only pick what you want, so you don't pay for what you don't use. Boiler cover runs up to £500 per year if your boiler's under 7 years old, or up to £200 if it's older. A £95 call-out fee applies. We've looked after over 15,000 customers, we're from UK Boiler Company Ltd, trading since 2014, and we're rated on Trustpilot.

Worcester Bosch CE fault FAQs

Seeing a CE code? We'll come and fix it for you.

Book a one-off repair and a Gas Safe registered engineer will sort it, or set up an ongoing Smart Plan boiler module so the next fault's covered. A service plan, not insurance — parts and labour included up to your cover limit.

Helpful links

• All Worcester Bosch fault codes
• EA / 227 fault — no flame & low pressure fix
• No heating? Book a repair
• Boiler & central heating cover
• More boiler guides on the blog
• Check an engineer on the Gas Safe Register