Worcester Bosch CE 207 Error Code: Meaning and How to Fix It

On a Worcester Bosch boiler, CE 207 means the water pressure in the central heating system has fallen too low for the boiler to run safely, so it has stopped. This Worcester Bosch CE 207 error code guide explains the pressure figures Worcester uses, how to top the system up through the filling loop, and what it means when the pressure keeps dropping.

Quick answer: CE 207 on a Worcester Bosch boiler means low system pressure. With the boiler cold, top the system up to between 1 and 1.5 bar using the filling loop, close the valves, then reset. This is a safe homeowner job. If the pressure falls again within days, there is probably a leak, so call a Gas Safe registered engineer.

What Does the Worcester Bosch CE 207 Error Code Mean?

CE 207 means the system pressure is too low. In the Worcester GB162 boiler user instructions, fault code 207 is listed as “the system pressure is too low (less than 0.2 bar)”, and the same manual shows a separate low pressure warning when pressure drops below 1.0 bar.

Worcester boilers with a text display show a two part code: letters for the type of fault and a number for the cause. Independent Worcester code lists we checked give the same low pressure meaning for CE 207 on domestic Greenstar boilers, including the 8000 range, but Worcester’s user manuals for those models do not print a full code table. Treat CE 207 as low pressure, and check the manual for your exact model if the advice below does not clear it.

Pressure matters because a sealed heating system needs enough water to circulate safely. When it drops too far, the boiler locks out rather than risk overheating. That is why the fix is usually simple: put the water back.

What Causes the CE 207 Error?

• Bleeding radiators. Letting air out also lets a little water out, and pressure falls each time.
• Slow loss over months. Sealed systems can lose small amounts of water over time, which is why Worcester asks you to check the gauge regularly.
• A leak. A weeping radiator valve, a joint under the floor or a fault inside the boiler can let water escape.
• Water escaping through the pressure relief discharge pipe. This short copper pipe usually runs from the boiler to outside. Water dripping from it is a job for an engineer.
• A faulty pressure sensor or other internal part. If the gauge reads normal but CE 207 shows, the boiler may be misreading the pressure.

How Do You Fix the CE 207 Error Yourself?

Topping up the pressure is a homeowner task that Worcester describes in its user manuals. Your boiler will have one of three filling loop types, so follow the steps for yours.

1. Let the system cool. Switch the heating off and wait until the radiators are cold, as Worcester’s 1 to 1.5 bar figure is a cold reading.
2. Find the gauge and filling loop. The gauge is on the boiler front or on the display. The filling loop is under the boiler.
3. Keyless filling link: pull the blue lever down and release it when the needle reaches 1 to 1.5 bar.
4. Keyed filling link: insert the key as your manual shows, open the valve slowly and close it when the needle reaches 1 to 1.5 bar.
5. External filling loop: unscrew the blanking caps, attach the braided hose hand tight, turn both valves 90 degrees to open, fill to 1 to 1.5 bar, close the valves, then remove the hose and refit the caps. Worcester notes that water regulations require you to disconnect an external loop after use.
6. If you overfill, bleed one radiator until the gauge is back between 1 and 1.5 bar, as Worcester’s Greenstar 8000 manual advises.
7. Reset the boiler. Greenstar i and Si models have a reset button. Greenstar 8000 models are reset by pressing two keys together until the fault clears, as shown in the user manual.

For more detail on each loop type, see our step by step guide on how to repressurise a combi boiler.

Safety: Only use the filling loop and the controls on the front of the boiler. Do not remove the casing, adjust the pressure relief valve or try to recharge the expansion vessel. If the pressure drops again soon after topping up, if water drips from the discharge pipe outside, or if CE 207 stays on with a normal gauge reading, call a Gas Safe registered engineer.

When Should You Call an Engineer?

Call an engineer if you need to top up more than once in a short period, because a healthy sealed system should hold its pressure. The HSE domestic gas safety FAQs state that anyone employed to work on gas appliances in homes must be Gas Safe registered, so choose a registered engineer and check their ID card.

• The pressure falls back below 1 bar within days or weeks.
• You see damp patches, stained ceilings or wet floors near pipes or radiators.
• Water is dripping from the copper discharge pipe outside.
• The gauge reads 1 to 1.5 bar but CE 207 does not clear.
• You cannot find or operate the filling loop.

Worcester does not publish standard repair prices for low pressure faults, as the cost depends on what is causing the loss. Ask for a quote once the engineer has found the cause.

What Do Worcester Pressure Readings Mean?

On Greenstar 8000 boilers the display shows pressure in coloured zones: green is normal, yellow is slightly low or high, and red is too low or too high.

How Can You Stop the CE 207 Error Coming Back?

• Check the pressure gauge regularly, as Worcester advises, and top up before it falls below 1 bar.
• Check the gauge after bleeding radiators and top up straight away if it has dropped.
• Fix small leaks quickly, as even a slow drip lowers the pressure over time.
• Have the boiler serviced every year by a Gas Safe registered engineer, as HSE advises, and ask them to check the expansion vessel.
• Keep an eye on running costs too: our gas bill calculator shows what your heating costs each month.

Worcester Bosch CE 207 Error Code FAQs

Checked October 2026. Sources: Worcester GB162 boiler user instructions (fault code table), Worcester Greenstar i System Compact user instructions, Worcester Greenstar Si Compact user instructions, Worcester Greenstar 8000 user instructions, HSE domestic gas safety FAQs.