Quick Answer
To reset a Worcester Bosch boiler, most Greenstar models require pressing and holding the reset button, or the up and down arrow buttons together, for 3 to 5 seconds until the display changes. Older Greenstar RI and CDi Classic models use the central heating temperature knob, turned to the reset position and held for around 5 seconds. Always note the fault code first, and never reset if the code indicates a serious fault such as D1, E9, or C1.
Before You Reset: Note the Fault Code
Take a photo or write down the fault code shown on the display before resetting. This does not affect the reset process itself, but it matters if the fault reappears and you need to contact a Gas Safe registered engineer, since the code helps them diagnose the issue faster.
Step-by-Step Reset Instructions by Model
| Model | Reset Method |
|---|---|
| Greenstar 8000, 4000, 2000, 1000 | Press and hold the up and down arrow buttons together for 3 to 5 seconds |
| Greenstar CDi Classic | Turn the central heating temperature knob to the reset position and hold for 5 seconds |
| Greenstar RI | Hold the reset button until the flashing blue light stops |
| Models with a dedicated reset button | Press and hold the reset button, usually marked with a reset icon, for 3 to 5 seconds |
If you cannot locate a reset button or the correct knob position for your specific model, check your boiler’s manual, since exact button placement varies across the Greenstar range.
What to Check Before Resetting
- Confirm the fault code is not one requiring immediate professional attention, such as D1 (sensor or overheat issue), E9 (heat exchanger problem), or C1 (fan problem)
- If the code relates to low pressure (often shown as A1 or code 2971), top up the system using the filling loop before resetting, since resetting alone will not fix a genuine low pressure fault
- Check whether the issue followed a recent power cut, which is one of the most common, and easiest to resolve, reasons a reset is needed
What Happens During the Reset
Once you release the reset button or return the knob to its normal position, the boiler should attempt to reignite within a minute or two. Listen for a clicking sound as it tries to relight. Give it this time before assuming the reset has failed.
When Resetting Doesn’t Work
A reset is not a repair. If the underlying cause of the lockout, such as a genuine gas supply issue, a persistent low pressure leak, or a component fault, has not been addressed, the boiler will detect the same problem and shut down again after resetting. If the fault code reappears immediately or repeatedly after resetting, stop attempting further resets and book a Gas Safe registered engineer rather than continuing to retry.
Preventing Future Lockouts
Having your Worcester Bosch boiler serviced annually by a qualified engineer catches many developing issues before they cause a full lockout, and is also required to keep most Worcester Bosch warranties valid. Keeping system pressure topped up and bleeding radiators when needed also reduces how often pressure-related resets are needed.
Frequently Asked Questions
How do I know if my Worcester Bosch boiler needs a reset?
Signs include a flashing blue light, a fault code on the display, no heating or hot water, or a sudden shutdown, often following a power cut or lockout.
Is it safe to reset a Worcester Bosch boiler myself?
Yes, for most fault codes a reset is safe to attempt yourself, though codes indicating a serious internal fault, such as D1, E9, or C1, should be left to a Gas Safe registered engineer.
Why does my Worcester Bosch boiler keep locking out after I reset it?
This means the underlying cause has not been resolved, since a reset only clears the fault display rather than fixing the fault itself.
Do all Worcester Bosch models reset the same way?
No, the method varies by model, from a dedicated reset button on newer Greenstar models to a temperature knob on older CDi Classic and RI models.
How long should I wait after resetting before calling an engineer?
Give the boiler a minute or two to attempt reignition; if the fault code reappears immediately or after a short period, it is time to call a Gas Safe registered engineer.