Worcester Bosch 2925 Fault Code: Causes, Fixes & Repair Costs
What does the Worcester Bosch 2925 fault code mean?
Fault code 2925 appears on the Worcester Bosch Greenstar 2000 range and indicates that the boiler's internal diagnostics have detected a problem with either the gas valve or the appliance control electronics (PCB). When this code is triggered, the boiler enters a hard lockout — it will not attempt to fire again until the fault has been investigated and cleared. Because both the gas valve and the PCB are safety-critical components, this fault almost always requires attention from a Gas Safe registered engineer. Note: code 2926 is closely related and points to the same two components; if your display shows 2926, the same diagnostic and repair process applies.
General guidance only — not a substitute for professional advice. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Faulty gas valve Common
The gas valve controls precisely how much gas enters the burner. Over time, internal components can wear, corrode, or seize, preventing the valve from opening, closing, or modulating correctly. When the boiler's control system detects that the valve is not responding as expected, it locks out and displays code 2925 as a safety measure.
- Faulty PCB (appliance electronics) Common
The printed circuit board acts as the boiler's central controller, sending and receiving signals to every component. PCBs are vulnerable to moisture ingress — even condensation inside the casing can cause short-circuits or component failure. A damaged PCB may misread signals from the gas valve or fail to send correct commands, triggering a 2925 lockout even if the gas valve itself is functioning normally.
- Wiring fault between gas valve and PCB Sometimes
Loose terminals, chafed cables, or corroded connectors on the wiring loom that links the gas valve to the PCB can cause intermittent signal failures. The boiler may interpret these as a component fault and lock out with code 2925, even though neither the valve nor the board is actually defective.
How to fix it
- Check that your gas supply is working DIY safe
Before anything else, confirm that other gas appliances in your home (hob, gas fire) are working normally. If there is no gas supply to the property, contact your gas supplier rather than investigating the boiler further.
- Attempt a single boiler reset DIY safe
Locate the reset button on your Greenstar 2000 — it is usually a flame symbol on the control panel. Press and hold for approximately 3 seconds. If the boiler fires up and runs normally, monitor it closely over the next hour. If code 2925 returns, do not keep resetting — repeated resets without resolving the underlying fault can mask a genuine safety issue.
- Do not open the boiler casing or touch internal components Gas Safe engineer
Even with the boiler switched off at the programmer, live voltage and gas-carrying components are present inside the casing. Removing the case or probing wiring without the correct equipment is dangerous and will void any remaining warranty. Leave all internal investigation to a qualified engineer.
- Contact a Gas Safe registered engineer for diagnosis Gas Safe engineer
A Gas Safe engineer will carry out a systematic check: testing the gas valve for correct electrical resistance and mechanical operation, inspecting the PCB for signs of water damage or burnt components, and checking the wiring loom between the two. This diagnosis usually takes 30–60 minutes and will confirm which component needs replacing.
- Gas valve replacement (engineer only) Gas Safe engineer
If the gas valve is found to be defective, the engineer will isolate the gas supply, remove the faulty valve, fit a manufacturer-approved replacement, and carry out a gas-tightness test before recommissioning the boiler. This work must only be performed by a Gas Safe registered engineer.
- PCB replacement or repair (engineer only) Gas Safe engineer
If the PCB is at fault, the engineer may be able to have it repaired by a specialist electronics company, which can be more cost-effective than a full replacement. If repair is not viable, a new PCB will be sourced and fitted. After replacement, the boiler's settings and parameters will need to be verified and recommissioned.
Parts you may need
- Gas valve (Greenstar 2000 compatible) · from £120
- PCB / control unit (Greenstar 2000) · from £180
- Gas valve wiring harness · from £35
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £200–£450, depending on the underlying cause.
Frequently asked questions
Can I reset a Worcester Bosch 2925 fault myself?
Yes, one reset attempt is fine and costs nothing. Hold the reset button for about 3 seconds and see if the boiler runs normally. If code 2925 comes back — especially after two or three resets — stop resetting and call a Gas Safe engineer. Continuously resetting a lockout fault without finding the cause can be unsafe.
How much does it cost to fix a Worcester Bosch 2925 fault?
For most people, the repair bill falls between £200 and £450 including parts, labour, and any call-out charge. A gas valve replacement typically costs £150–£300 all-in, while a PCB replacement usually sits between £200–£400. If both components need attention, or if the job involves awkward access, costs can rise above this range. A Gas Safe engineer will give you a firm quote after diagnosis.
Is fault code 2926 the same as 2925?
They are very closely related. Both codes on the Greenstar 2000 point to the gas valve and appliance electronics as the suspected cause, and the diagnostic and repair process is identical. If your boiler is displaying 2926, follow the same steps as for 2925 and have a Gas Safe engineer investigate both components.
My Greenstar 2000 is over 10 years old — is it worth repairing?
As a rough rule of thumb, if your boiler is 12 or more years old and the repair quote exceeds around £600, it is often more economical to replace it with a new, more efficient model. Boilers of that age are also more likely to develop further faults in the near future. Speak to your Gas Safe engineer — a reputable one will give you an honest assessment of whether repair or replacement makes better financial sense.