Worcester Bosch Greenstar 8000 Life Fault codes & diagnostics

53 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

CombiSystem Natural GasLPG 30-50 kW 2019-present

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2 Emergency 39 High 12 Low

All 53 documented codes

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1-A2

Your boiler has detected an internal communication error between its internal components, meaning it cannot operate safely and has shut itself down.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
1-d4

Your boiler is reporting an issue with your home's solar water heating system, which is keeping it from communicating with the main heating unit.

Low Engineer only £120-250

Parts commonly replaced

  • Solar module
  • Solar sensor
  • Wiring harness

Related codes

1-E1

Your boiler's computer is reporting a configuration mismatch between its internal components, meaning it has paused operation to prevent incorrect performance.

High Engineer only £150-300

Parts commonly replaced

  • Control Unit
  • Main PCB
1-E2

Your boiler is displaying a status check of its internal control software, which is usually a temporary communication glitch rather than a mechanical failure.

Low DIY-safe

What to check first

  1. Switch off the power supply to the boiler at the electrical spur or fuse box
  2. Wait for 60 seconds to allow the internal electronics to fully reset
  3. Switch the power back on and check if the display returns to normal

Parts commonly replaced

  • Key interface PCB
  • Programmer module

Related codes

1-E3

Your boiler is failing to recognise its internal settings chip, which means it cannot operate correctly until the electronic data connection is restored.

High Engineer only £150-350

Parts commonly replaced

  • Coding plug
  • Main Printed Circuit Board - PCB
1-E4

Your boiler's electronic brain is unable to read or recognise the specific configuration key that tells it how to operate your heating system.

High Engineer only £120-250

Parts commonly replaced

  • Coding plug
  • Main control board

Related codes

1-EA

Your boiler's internal computer is experiencing a communication or software error, causing it to shut down for safety.

High Engineer only £150-300

Parts commonly replaced

  • Main Control Board (PCB)
1-Eb

Your boiler's internal computer is reporting an issue with its software configuration that prevents it from starting up correctly.

High Engineer only £120-250

Parts commonly replaced

  • Control unit
  • Main PCB
Showing 11–20 of 53
202

Your boiler is temporarily pausing to wait for the system temperature to drop, which is a normal protective feature to prevent frequent switching on and off.

Low Engineer only
203

Your boiler is perfectly healthy and is simply waiting for you to turn on a tap or adjust your heating.

Low DIY-safe

What to check first

  1. Check your thermostat or programmer settings to ensure there is a demand for heat
  2. Turn on a hot water tap to see if the boiler activates for hot water
  3. No further action is required as this is a normal status code

Related codes

204

Your boiler has detected that the water inside the unit is getting hotter than it should be and has switched itself off to prevent overheating.

High Engineer only £150-300

Parts commonly replaced

  • Central Heating Pump
  • Plate Heat Exchanger
  • NTC Temperature Sensor

Related codes

208

Your boiler has been accidentally switched into a testing mode used by engineers to check emissions, rather than a sign of a mechanical breakdown.

Low DIY-safe

What to check first

  1. Locate the chimney sweep button on the boiler control panel, often marked with a chimney or flue symbol.
  2. Press and hold the button for 5 seconds to exit the test mode.
  3. Restart the boiler if it does not automatically return to its normal display screen.
224

Your boiler has detected that it has become too hot and has automatically shut down to prevent any internal damage.

High Engineer only £150-300

Parts commonly replaced

  • High limit thermostat
  • Pump
  • Diverter valve
  • Heat exchanger

Related codes

227

Your boiler is trying to start but cannot detect the flame needed to produce heat.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

228

Your boiler has detected an internal error where it believes a flame is present when it should be off, which is a safety lockout preventing the unit from starting.

Emergency Engineer only £150-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Flame rectification electrode
  • Wiring harness

Related codes

306

Your boiler has detected that a flame is still present even though it has tried to shut off the gas supply, which could indicate a safety issue.

Emergency Engineer only £150-350

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
  • Flame rectification electrode

Related codes

Showing 21–30 of 53
360

Your boiler's internal computer chip does not match the specific model settings, meaning it cannot communicate correctly to start the heating process.

High Engineer only £150-250

Parts commonly replaced

  • Code Plug
  • PCB (Main Control Board)
815

Your boiler is struggling to accurately read the temperature of the water circulating through your heating system, so it has stopped working as a safety precaution to prevent overheating.

High Engineer only £150-250

Parts commonly replaced

  • Low loss header sensor
  • Wiring harness
1010

Your boiler's electronic control panel has lost its connection, meaning the main brain cannot communicate with the rest of the system to turn on your heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • EMS-Bus wiring harness
  • Control unit PCB
  • Key interface
1017

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

High DIY-safe £80-120

What to check first

  1. Locate the external filling link or key under the boiler casing.
  2. Open the filling valve slowly to allow mains water to enter the system.
  3. Monitor the pressure gauge on the front display until it reaches the green zone, typically between 1.0 and 1.5 bar.
  4. Close the valve securely.

Parts commonly replaced

  • Filling link
  • Pressure relief valve
  • Pressure sensor

Related codes

1018

Your boiler is simply reminding you that it is due for its regular annual safety inspection and service.

Low Engineer only £90-140
1021

Your boiler is struggling to accurately detect the temperature of your hot water, which means it will likely stop producing hot water until the faulty sensor is replaced.

High Engineer only £120-220

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC temperature sensor
1037

Your boiler is struggling to detect the current temperature outside, so it is using a default setting to keep your home warm.

Low Engineer only £100-200

Parts commonly replaced

  • Outside temperature sensor
  • Wiring harness
1065

Your boiler is currently unable to accurately read the water pressure within the system, so it has safely stopped working to prevent potential damage.

High Engineer only £150-250

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness
1068

Your boiler has lost signal from the sensor outside your home that measures the temperature, so it is defaulting to a standard operating mode.

Low Engineer only £120-200

Parts commonly replaced

  • Outside temperature sensor
1073

Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside it, likely due to a loose wire or a faulty sensor connection.

High Engineer only £120-220

Parts commonly replaced

  • Flow temperature sensor
  • Wiring harness

Related codes

Showing 31–40 of 53
1074

Your boiler has lost the connection to a sensor responsible for monitoring the temperature of the water inside, causing it to stop heating your home to prevent potential damage.

High Engineer only £150-250

Parts commonly replaced

  • NTC flow temperature sensor
  • Wiring harness
  • PCB

Related codes

1075

Your boiler has stopped working because one of its internal temperature sensors is giving a faulty reading that suggests a short circuit.

High Engineer only £150-250

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness

Related codes

1076

Your boiler has lost its connection to an internal temperature sensor, so it has safely shut down to prevent overheating.

High Engineer only £150-250

Parts commonly replaced

  • NTC temperature sensor
  • Wiring harness
2920

Your boiler has detected that the internal ignition system is staying on longer than it should while the flame is lit, which is causing it to shut down for safety.

High Engineer only £150-£300

Parts commonly replaced

  • Ionisation electrode
  • Ignition lead
  • PCB (Printed Circuit Board)

Related codes

2924

Your boiler has detected an internal communication failure within its gas control system, meaning it cannot safely regulate the fuel supply to heating components.

High Engineer only £250-400

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

2925

Your boiler is struggling to control the gas supply it needs to heat your home, so it has stopped working for safety reasons.

High Engineer only £250-450

Parts commonly replaced

  • Gas valve
  • Main PCB

Related codes

2927

Your boiler has stopped because the internal flame went out unexpectedly while it was trying to heat your water or home.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe

Related codes

2946

Your boiler's computer chip is not communicating correctly with the main control board, preventing it from starting up safely.

High Engineer only £150-300

Parts commonly replaced

  • Code plug
  • PCB (Main control board)
2948

Your boiler is struggling to stay lit at a low power setting, which stops it from providing heating or hot water effectively.

High Engineer only £180-350

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification sensor

Related codes

2950

Your boiler is trying to start but the flame is failing to establish, which means it cannot produce heat or hot water.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe

Related codes

Showing 41–50 of 53
2963

Your boiler has detected that the water temperature readings inside the system are conflicting or missing, causing it to shut down for safety.

High Engineer only £150-250

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness
  • PCB

Related codes

2964

Your boiler has detected that water is not flowing through its internal heating system fast enough to operate safely.

High Engineer only £150-350

Parts commonly replaced

  • Diverter valve
  • System filter
  • Pump

Related codes

2964 B

Your boiler has detected that water is not circulating properly inside it, which is preventing it from heating your home or water safely.

High Engineer only £120-250

Parts commonly replaced

  • Central heating pump
  • Flow sensor
  • Flow temperature sensor

Related codes

2965

Your boiler has detected that the water inside the system is becoming dangerously hot, so it has safely shut down to prevent damage.

High Engineer only £150-350

Parts commonly replaced

  • NTC Temperature Sensor
  • Primary Heat Exchanger
  • Pump

Related codes

2965 B

Your boiler has detected that the water inside isn't moving properly, causing it to overheat and shut down for safety.

High DIY-safe £120-250

What to check first

  1. Check your boiler's pressure gauge and ensure it is between 1 and 1.5 bar; top up using the internal filling link if it is too low.
  2. Ensure all radiator valves are fully open to allow water to circulate properly.
  3. Turn the boiler off at the fused spur for 60 seconds and switch it back on to reset the system.

Parts commonly replaced

  • Central heating pump
  • Flow sensor
  • Printed Circuit Board (PCB)

Related codes

2966

Your boiler is overheating rapidly because the water inside isn't circulating properly to carry the heat away.

High Engineer only £150-350

Parts commonly replaced

  • Pump
  • Diverter valve
  • Heat exchanger

Related codes

2966 B

Your boiler is overheating because water is not circulating through your heating system fast enough, likely due to low pressure or a blockage.

High DIY-safe £120-350

What to check first

  1. Check your boiler pressure gauge; if it is below 1 bar, use the internal filling link to top it up to 1.5 bar.
  2. Ensure all radiator valves and any isolation valves around the boiler are fully open.
  3. Restart the boiler using the reset button to see if the error clears.

Parts commonly replaced

  • Central heating pump
  • Diverter valve
  • Primary flow sensor

Related codes

2967

Your boiler has detected that the water temperature is changing in a way that suggests there might be a blockage or a problem with how the water is flowing inside the unit.

High Engineer only £180-350

Parts commonly replaced

  • NTC Temperature Sensor
  • Primary Heat Exchanger
  • Central Heating Pump

Related codes

2967 B

Your boiler has detected that water is not circulating correctly through the system or is heating up unevenly, causing it to shut down for safety.

High Engineer only £150-£300

Parts commonly replaced

  • Central heating pump
  • NTC temperature sensor
  • Diverter valve
2970

Your boiler has detected that the water pressure in your heating system is dropping significantly faster than it should, which usually points to a leak somewhere in your radiators or pipework.

High Engineer only £150-350

Parts commonly replaced

  • Pressure relief valve
  • Expansion vessel
  • Heating system pipework (leak repair)

Related codes

Showing 51–53 of 53
2970 B

Your boiler has detected that the water pressure in your heating system is falling away much faster than it should, which usually points to a leak somewhere in your radiators or pipes.

High DIY-safe £120-250

What to check first

  1. Check all radiators, valves, and the boiler itself for visible signs of water leakage or damp patches
  2. Locate the external filling loop connected to your boiler pipes
  3. Open the valves on the filling loop to allow cold mains water into the system until the pressure gauge on the front display reads roughly 1.5 bar, then securely close the valves

Parts commonly replaced

  • Pressure Relief Valve (PRV)
  • Expansion Vessel
  • Heating system pipework or radiator valves

Related codes

2971

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

High DIY-safe £0-£120

What to check first

  1. Locate the external or internal filling link (a silver braided hose or a small plastic key) connected to your boiler.
  2. Gradually open the valves on the filling link until you hear water flowing.
  3. Watch the pressure gauge on the front of the boiler until it reaches 1.5 bar, then close both valves tightly.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Expansion vessel

Related codes

2971 B

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the external filling loop or internal key filling device connected to your boiler pipes
  2. Slowly open the valve to allow water to enter the system while watching the pressure gauge on the boiler front
  3. Stop filling when the needle reaches the green zone, usually between 1.0 and 1.5 bar, then tightly close the valve

Parts commonly replaced

  • Pressure relief valve
  • Expansion vessel
  • Filling loop

Related codes