Eco Happy (Solar Expert)

Published February 23, 2024

If your Worcester boiler gives up on the coldest winter’s day, you may have a huge problem. Not to mention, your family will not be too pleased, either. However, the problem might not be as bad as it seems. It may be a simple reset fault condition. But then you need to know how to reset a Worcester boiler.

You may need to reset a Worcester boiler if there is low water pressure, after a power outage, or if there is a glitch in the boiler’s control panel. Other times, it could be because of frozen pipes, the system overheating, an airlock, or maybe even loose wires.

Don’t worry, though, because Eco Happy has a comprehensive DIY Worcester boiler troubleshooting guide to help you understand how to reset a Worcester boiler.

When To Reset Your Worcester Boiler

To understand abnormal boiler system behaviour, you first need to understand indications of normal operation. During normal operation, your boiler keeps your home warm and gives you hot water when you need it. Your Worcester boiler should have a low, humming sound, the pressure gauge should be in the green zone, and there should be no visible smoke.

Signs necessitating a reset

There are times, though, that require that you reset a Worcester boiler to get it fully operational again. These are some of those times:

  • Fault indicator
  • When the boiler system shuts down
  • Inconsistent heating
  • Fluctuations on the pressure gauge
  • Loss of hot water (specifically on a combi boiler)

How To Reset A Worcester Boiler

Remember to be safe before all else, but here is how to do a DIY boiler reset on a Worcester Bosch boiler.

Safety precautions

Safety comes first, so always take precautions when you reset your boiler. If there are any signs that you’re dealing with a broken boiler – like if there’s excessive heat or if the fault persists – you need to call in a Gas Safe-registered engineer. Sometimes, it’s better to err on the side of caution and call for help.

Reset button method

To reset a Worcester Bosch boiler is fairly simple:

  1. Locate the display panel. On most Worcester Bosch boilers, this round display is near the bottom of the boiler control panel’s front.
  2. Locate the up and down arrows on the right side of the display.
  3. Press and hold both arrows simultaneously for 5 seconds until the display blinks off.
  4. Release the arrows and wait for the reset process to complete.

Model-specific reset instructions

To reset a Worcester boiler, you simply need to press the boiler reset button. Hold it for five seconds, and the light will go off and the boiler will reset. This applies to the following boilers: Greenstar 8000 Life Combi, Greenstar 8000 Life System, Greenstar 8000 Life Regular, Greenstar 2000 Combi, Greenstar 2000 System, and the Greenstar 2000 Regular.

However, if you have a Greenstar CDi Classic Combi, a Greenstar CDi Classic System, or a Greenstar CDi Classic Regular, the boiler reset process is a little different. You need to turn the central heating temperature knob anticlockwise to the “Reset” position. Hold it in this position for five seconds and release it for your Worcester boiler to reset.

On the Greenstar Heatslave boilers, the boiler reset button is situated behind the front panel. You need to remove the front panel by pulling the bottom of the panel out and lifting it to remove it and access the Burner Reset Button. If the burner reset button doesn’t resolve the issue, you may need to try the alternate reset buttons, but it’s best to refer to your user manual for full details.

For a Worcester Greenstar SI boiler reset and a Worcester CDi Compact boiler reset, you would press the boiler reset button for around five seconds. If there is a fault, the Worcester Greenstar SI boiler reset button will flash once every second, and there will be a blue flashing light (the main indicator light). After the reset, everything should return to normal operation.

If you need to do a Junior boiler reset, the red reset light flashes. Press the red reset light for a couple of seconds, and the light will stop. Then, run your hot water tap for a few moments, and your Junior boiler reset will be complete.

Decoding Worcester Boiler Error Codes

Let’s look at the most common Worcester Bosch boiler fault codes next so we can quickly resolve the issue and get the heat back on for a happier family. The sooner you get to the source of the problem, the sooner it can be fixed. That is why the alert code is displayed as a fault code to help you quickly find the problem. After a reset, if the alert code is still displayed or the reset fails, call in a professional.

Quick tip: Always keep records of any displayed fault code and when it occurred, as well as if the common fault codes were adequately resolved with a simple reset.

Error code: EA

  • Meaning and implications: There is a problem with the boiler’s ignition. The boiler cannot light a flame or keep a flame going.
  • Troubleshooting tips: Check that the gas valve is open and that there are no gas leaks. Check that there is proper ventilation.
  • DIY solutions for user-friendly codes: Reset the boiler.
  • When to seek professional assistance: If the reset fails or if the error continues, call in a boiler engineer. If there is a gas leak, call a Gas Gas engineer immediately.

Error code: D1

  • Meaning and implications: There is a water pressure problem, and the pressure is too low to operate the boiler safely.
  • Troubleshooting tips: Check that the pressure gauge is within the green zone. If not, refer to the user manual and use the filling loop to top up the pressure.
  • DIY solutions for user-friendly codes: Bleed your radiators.
  • When to seek professional assistance: If the error persists, call a Gas Safe boiler engineer to assist.

Error code: E9

  • Meaning and implications: There is a problem with the boiler’s main heat exchanger, fan, or a damaged sensor. A blocked or damaged fan will affect combustion.
  • Troubleshooting tips: Look for blockages around the fan or in the flue and remove them.
  • DIY solutions for user-friendly codes: Reset the boiler.
  • When to seek professional assistance: If the fan or sensor needs to be replaced, or if the error continues, call in a boiler engineer to assist.

Error code: C1

  • Meaning and implications: There may be a problem with the condensate pipe or pump.
  • Troubleshooting tips: Check for any blockages in the condensate pipe and clear any obstructions. If the weather is icy, the pipes may be frozen.
  • DIY solutions for user-friendly codes: Clear any blockages and thaw any iced pipes. Then reset the boiler.
  • When to seek professional assistance: If the error persists or if the condensate pump needs replacing, call a boiler engineer to assist.

Error code: A1

  • Meaning and implications: There may be a wiring fault.
  • Troubleshooting tips: Check that all wires are stable, then reset the boiler.
  • DIY solutions for user-friendly codes: Tighten loose connections and reset the boiler.
  • When to seek professional assistance: If the error continues or the wiring needs to be replaced, call in a Gas Safe-registered engineer.

Preventive Maintenance

It’s very important to service your boiler regularly. Most boiler engineers recommend services happen at least once a year. It may even be a condition of the manufacturer’s guarantee. Just like a car would break down if left unattended, a boiler also needs more than a boiler reset from time to time.

A Worcester Bosch boiler that is less than 12 years old but out of guarantee could qualify for a Worcester Bosch boiler maintenance plan. Provided by Domestic & General Services Limited, you get an annual service, regular maintenance tips, and repairs up to £1,500 if your boiler stops working.

There are also simple DIY maintenance tasks that you can perform to keep your central heating system working efficiently, such as bleeding your radiators regularly or power flushing your central heating system.

Your boiler system will build up debris, rust, and other unwanted minerals and materials over time. You could prevent this by installing a magnetic filter on the return pipe to your boiler. By keeping out all these tiny particles, your boiler system will last a lot longer and give you fewer hassles in the long run.


I cannot find the reset button on my Worcester boiler

Your reset button may be on the thermostat dial (a.k.a the temperature dial). If you turn it to the left, it enters reset mode. Hold it in this position for 5 seconds and then return it to its original temperature setting.

What does the flashing blue mains light mean on Worcester boilers?

The flashing blue light means there is a fault and usually shows a fault code. Consult your user manual for the exact error or call in a heating engineer to help you fix the problem.


Resetting your boiler can seem scary. However, modern boilers, like those from Worcester, have clear indications with an alert code and a fault indicator to tell you when it’s time to hit the reset light. And most times, your boiler will start behaving again.

Worcester boilers are well-made and can last a long time. Remember to schedule regular maintenance and call in professional Gas Safe engineers, like Eco Happy, when you need a helping hand.

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