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Worcester Bosch Boiler CE 207 / H07 Error Code

Heating system water pressure too low on Worcester Bosch boilers.

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CE 207 / H07
Easy DIY fix

There isn't enough water pressure in the sealed heating circuit for the boiler to run. Pressure usually drops after radiators have been bled, through a small leak on a valve or joint, or when the relief valve has discharged. On Greenstar models Worcester asks you to recharge once the gauge falls below 1 bar (0.8 bar on the Greenstar 2000).

Compatible models

The code itself appears only in Worcester's operating instructions for GB162 V2 commercial boilers (GB162-50 to GB162-100 V2). Domestic Greenstar i, 2000, 8000 Life and 8000+ manuals give the low-pressure limits and top-up method without this code, so check your own manual for what your boiler displays.

Also shown as

Worcester's GB162 V2 commercial boiler manual lists both CE207 and H07 for low water pressure. Domestic Greenstar manuals describe the warning as a low reading on the gauge or display rather than a code; the Greenstar 8000 Life alternates LoPr with the reading and stops working at or below 0.2 bar.

Difficulty

Most people can clear this one at home with simple checks.

Not sure you are reading the code right? See how to read Worcester Bosch boiler codes.

Safety first: never take the casing off a gas boiler. If you smell gas, open windows, don't use light switches, turn the gas off at the meter if you can and call your gas emergency number from outside. A carbon monoxide alarm going off means the same: switch the boiler off, get fresh air and call.

How to fix Worcester Bosch CE 207 / H07

  1. Read the gauge with the heating off

    Let the system cool, then check the pressure gauge or the reading on the display. Worcester's target on the Greenstar i is between 1 and 1.5 bar when cold.

  2. Top up through your filling link

    Use whichever filling method your boiler has, exactly as the user manual shows. With a keyless filling link you pull the blue lever down and let go at 1 to 1.5 bar. A keyed link needs the filling key turned first, then you open the white knob and close it again at the right reading. An external filling loop has a hose and two valves that you open a quarter turn, close at 1 to 1.5 bar, and then disconnect before refitting the caps.

  3. Let some out if you overshoot

    Gone past 1.5 bar? Bleed one radiator with a radiator key until the gauge falls back into the 1 to 1.5 bar band.

  4. Reset and keep an eye on it

    Press reset if the boiler hasn't restarted on its own, then check the gauge every day or two. Look for damp under radiator valves and around visible pipework.

When to call a technician

Having to top up again and again usually means a leak or corrosion somewhere in the system, according to Worcester's Greenstar 8000+ manual. Ask your installer or a Gas Safe engineer to track it down rather than keep refilling.

Parts linked to CE 207 / H07

These are the parts an engineer usually checks for this code. They sit inside the sealed casing, so leave them to a Gas Safe registered engineer.

Frequently asked questions

Which Worcester Bosch models show the CE 207 / H07 code?

The code itself appears only in Worcester's operating instructions for GB162 V2 commercial boilers (GB162-50 to GB162-100 V2). Domestic Greenstar i, 2000, 8000 Life and 8000+ manuals give the low-pressure limits and top-up method without this code, so check your own manual for what your boiler displays.

Can I fix Worcester Bosch CE 207 / H07 myself?

Usually, yes. Most CE 207 / H07 problems clear with simple checks you can do at home. Start with the first step above: read the gauge with the heating off.

Other Worcester Bosch boiler codes

Last reviewed 2026-10-21. Codes and steps can vary by model; check your owner's manual.

Sources we checked