Worcester Bosch Greenstar 8000 Life/Style Fault codes & diagnostics

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

CombiSystemRegular Natural GasLPG 30-50 kW 2019-present
GC Numbers 47-108-9447-108-9547-108-9647-108-9747-108-9847-108-9947-114-1647-114-1747-114-1847-114-1947-114-2047-114-2141-611-3041-611-3141-611-3241-611-3341-611-3441-611-3541-611-3641-611-3741-611-3841-611-3944-108-4144-108-4244-108-4344-108-4444-108-4544-108-46

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Severity at a glance

Each cell = one fault code. Hover to identify.
2 Emergency 110 High 11 Medium 40 Low
Just want the most common Worcester Bosch Greenstar 8000 Life/Style faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 163 documented codes

Tap any card for details

1-A1

Your boiler is currently stuck in a temporary startup phase and is waiting for everything to be ready before it begins heating.

Low DIY-safe £0-90

What to check first

  1. Wait 15 minutes to see if the boiler clears the code automatically
  2. Ensure your thermostat is calling for heat or hot water
  3. Restart the boiler using the power button if the code persists for more than 30 minutes

Parts commonly replaced

  • No parts usually required
  • Control PCB (if code persists indefinitely)

Related codes

Full explanation for 1-A1
1-A2

Your boiler has detected an internal communication error or a software glitch that is preventing the system from starting up safely.

High Engineer only £120-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 1-A2
1-A3

Your boiler's heating power has been manually limited to a lower setting, which might prevent your home from reaching your desired temperature properly.

Low DIY-safe £0-80

What to check first

  1. Navigate to the boiler's service menu using the touchscreen or buttons.
  2. Locate 'Service Function 3-b1' in the settings.
  3. Check if the percentage value is set lower than required and adjust upward if more heat is needed.

Related codes

Full explanation for 1-A3
1-A5

Your boiler has detected that the internal water temperature is higher than it should be, causing the system to shut down to prevent damage.

High Engineer only £120-£280

Parts commonly replaced

  • Flow temperature sensor (NTC)
  • Circulation pump
  • Main heat exchanger

Related codes

Full explanation for 1-A5
1-A6

Your boiler is receiving a command from your smart thermostat or heating controller that it cannot currently process, often due to a communication glitch or a sensor reading incompatibility.

Low DIY-safe £0-120

What to check first

  1. Check that your room thermostat or smart hub is powered on and has batteries
  2. Turn your boiler off and on again using the power button to reset the communication link
  3. Ensure your smart heating schedule is not requesting an impossibly high temperature

Parts commonly replaced

  • RF Receiver
  • Smart Thermostat
  • Flow Temperature Sensor

Related codes

Full explanation for 1-A6
1-A7

Your boiler has detected an issue with a temperature sensor normally used in more complex heating systems, often meaning a sensor is faulty or incorrectly configured.

Medium Engineer only £90-180

Parts commonly replaced

  • Hydraulic header temperature sensor
  • NTC thermistor
  • Wiring harness
Full explanation for 1-A7
1-b2

Your boiler has detected that hot water is being drawn through the system, often serving as an advisory notification rather than a breakdown.

Low DIY-safe £0-120

What to check first

  1. Check that all hot water taps in the property are fully closed
  2. Inspect for any dripping taps or leaking shower heads
  3. Monitor the display to see if the code clears once water usage stops

Parts commonly replaced

  • DHW Flow Turbine
  • Flow Sensor

Related codes

Full explanation for 1-b2
1-b3

Your boiler has detected that the hot water is getting too hot, likely due to a sensor measurement issue or a temporary building of heat in the system.

Medium DIY-safe £90-180

What to check first

  1. Turn off the hot water tap and wait for the boiler to cool down
  2. Press the 'Reset' button on the boiler display panel
  3. Monitor the boiler to see if the hot water temperature stabilises

Parts commonly replaced

  • DHW Temperature Sensor (NTC thermistor)
  • Wiring harness pins

Related codes

Full explanation for 1-b3
1-b4

Your boiler is struggling to accurately measure the temperature of the water going to your taps, which might result in the water being too hot or too cold.

Medium Engineer only £100-£220

Parts commonly replaced

  • Domestic Hot Water (DHW) Temperature Sensor
  • Wiring harness
  • NTC Thermistor

Related codes

Full explanation for 1-b4
1-b7

Your boiler is receiving an incorrect or unusual temperature request for your hot water from the external heating controls.

Low DIY-safe £0-120

What to check first

  1. Check your thermostat or heating app to ensure the hot water temperature is set to a normal level (typically 50-60°C).
  2. Turn the boiler off and back on at the main isolation switch to reset the communication between the controller and the boiler.
  3. Ensure any smart home batteries in your thermostat are not low, as this can cause communication errors.

Parts commonly replaced

  • External Heating Controller
  • RF Receiver
  • Communication Cable

Related codes

Full explanation for 1-b7
Showing 11–20 of 163
1-b8

Your boiler is struggling to control its power level correctly, which may lead to it shutting down to prevent damage.

High Engineer only £120-350

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)
  • Burner Control Unit
Full explanation for 1-b8
1-C1

Your boiler has detected that the flame has gone out or isn't burning correctly during operation, causing the system to shut down for safety.

High Engineer only £120-£350

Parts commonly replaced

  • Ionisation Electrode
  • Ignition Lead
  • Gas Valve
  • PCB

Related codes

Full explanation for 1-C1
1-C2

Your boiler's internal pump is running at an incorrect speed, which could lead to your heating or hot water not working effectively.

Medium DIY-safe £220-450

What to check first

  1. Turn the boiler off at the fused spur switch for 30 seconds and turn it back on to reset the electronics.
  2. Check that all radiator valves are fully open to ensure water can flow freely.
  3. Listen for any unusual grinding or humming noises coming from the boiler casing.

Parts commonly replaced

  • Internal circulation pump
  • PCB (Printed Circuit Board)
Full explanation for 1-C2
1-C4

Your boiler is displaying the current outdoor temperature because an external weather sensor is connected, which is a normal status reading rather than a breakdown.

Low DIY-safe

What to check first

  1. Check if the display returns to the normal temperature screen automatically
  2. Press the 'Back' or 'Reset' button once to clear the informational message
  3. Ensure the external sensor is not obstructed by snow or debris
Full explanation for 1-C4
1-C6

Your boiler has detected that the water pressure in the system is outside of the normal operating range, which often means it needs topping up or has been overfilled.

Low DIY-safe £0-120

What to check first

  1. Locate the internal or external filling link (often a blue lever or braided hose under the boiler).
  2. Slowly open the valve(s) until the pressure gauge on the display shows between 1.0 and 1.5 bar.
  3. Ensure both valves are closed tightly once the correct pressure is reached.

Parts commonly replaced

  • Filling link
  • Pressure sensor
  • Expansion vessel recharge

Related codes

Full explanation for 1-C6
1-d1

Your boiler is reporting an issue with the solar panel temperature sensor, which usually means the system is detecting an unusual reading from your solar thermal panels.

Low Engineer only £90-180

Parts commonly replaced

  • Solar collector temperature sensor
  • Solar module wiring
  • Control PCB
Full explanation for 1-d1
1-d2

Your boiler is reporting a minor sensor issue related to your solar hot water system, but it is not a breakdown of the central heating itself.

Low Engineer only £90-180

Parts commonly replaced

  • Solar cylinder temperature sensor
  • NTC thermistor
  • Wiring harness
Full explanation for 1-d2
1-d3

Your boiler is reporting an issue with the pump that circulates fluid between your solar panels and the water tank.

Medium Engineer only £180-350

Parts commonly replaced

  • Solar pump station
  • Solar temperature sensor
  • Solar control module
Full explanation for 1-d3
1-d4

Your boiler is reporting a communication problem or a technical fault with your solar heating system, though your central heating should continue to work.

Low DIY-safe £90-250

What to check first

  1. Locate the solar control module or pump station.
  2. Check if any cables connecting the solar system to the boiler have come loose.
  3. Restart the boiler using the reset button on the display.

Parts commonly replaced

  • Solar module (MS100/MS200)
  • Wiring harness
  • Solar temperature sensor
Full explanation for 1-d4
1-d5

Your boiler is letting you know it is currently in the process of automatically topping up the water pressure in the system.

Low DIY-safe

What to check first

  1. No action is required as this is an advisory message, not a fault
  2. Wait for the boiler to complete the filling cycle
  3. Monitor the display to ensure the code clears once the correct pressure is reached

Related codes

Full explanation for 1-d5
Showing 21–30 of 163
1-E1

Your boiler's internal computer is reporting an error with its software version or internal memory communication.

High Engineer only £250-550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Code Plug

Related codes

Full explanation for 1-E1
1-E2

Your boiler's internal computer is reporting an issue with its software version, which may lead to communication problems between the controls and the boiler.

High Engineer only £90-250

Parts commonly replaced

  • Display PCB
  • Main Control Board (Heatronic)

Related codes

Full explanation for 1-E2
1-E3

Your boiler's internal electronic computer chip is either missing, loose, or incompatible with the unit's software.

High Engineer only £120-250

Parts commonly replaced

  • Code Plug
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 1-E3
1-E4

Your boiler has detected an internal software conflict or an incorrect configuration chip, preventing it from operating correctly.

High Engineer only £120-280

Parts commonly replaced

  • Coding Plug
  • Main PCB

Related codes

Full explanation for 1-E4
1-EA

Your boiler's internal computer has identified a mismatch or issue with its software version, which prevents it from operating correctly.

High Engineer only £120-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Code Plug
Full explanation for 1-EA
1-Eb

Your boiler's internal computer components are having trouble communicating because their software versions do not match.

Low DIY-safe £0-120

What to check first

  1. Press the 'Reset' button on the front display panel and wait for the boiler to restart.
  2. Switch the boiler off at the main electrical spur, wait 30 seconds, and switch it back on.
  3. Check if any external smart controls or accessories have recently been updated or replaced.

Parts commonly replaced

  • Control Box (PCB)
  • HMI Display Module

Related codes

Full explanation for 1-Eb
200

Your boiler is not currently experiencing a fault; it is simply indicating that it is actively running to provide central heating for your home.

Low DIY-safe

What to check first

  1. Check your thermostat to ensure the target temperature is set correctly.
  2. Wait for the house to reach temperature; the code will change once the heating demand is met.
  3. No action is required as this is an operational status code, not an error.

Related codes

Full explanation for 200
201

Your boiler is simply letting you know that it is currently busy heating up water for your taps or shower.

Low DIY-safe

What to check first

  1. No action is required as this is an operational status message rather than a breakdown.
  2. Check that your hot water taps are fully turned off.
  3. Wait for the boiler to finish its current cycle, after which the code should disappear.

Related codes

Full explanation for 201
Showing 31–40 of 163
202

Your boiler is temporarily resting to prevent it from turning on and off too frequently, which helps protect the internal components from unnecessary wear.

Low DIY-safe

What to check first

  1. Check that your room thermostat is set higher than the current room temperature
  2. Ensure all radiator valves (TRVs) are turned open to allow heat to circulate
  3. Wait up to 15 minutes for the anti-cycle timer to expire and the boiler to restart automatically

Related codes

Full explanation for 202
202 O

Your boiler is taking a short, programmed break to prevent itself from turning on and off too frequently, which helps protect the internal components and improve efficiency.

Low DIY-safe

What to check first

  1. Wait 15 to 30 minutes for the timer to finish automatically
  2. Ensure all radiator valves are fully open to allow heat to dissipate
  3. Check that your room thermostat is set higher than the current room temperature

Related codes

Full explanation for 202 O
203

Your boiler is working correctly and is simply waiting for a signal from your thermostat or timer to start heating.

Low DIY-safe

What to check first

  1. Check that your room thermostat is turned up higher than the current room temperature.
  2. Ensure your heating programmer or app is set to an 'On' period.
  3. Check if your wireless thermostat has run out of batteries.

Related codes

Full explanation for 203
203 0

Your boiler is working correctly but currently has no request from your thermostat or taps to provide heating or hot water.

Low DIY-safe

What to check first

  1. Check that your room thermostat is turned up higher than the current room temperature
  2. Ensure your heating programmer or timer is set to 'On'
  3. Check if the batteries in your wireless thermostat need replacing

Related codes

Full explanation for 203 0
204

Your boiler has sensed that the water temperature has risen above the level it was set to reach, leading it to shut down for safety.

High DIY-safe £120-£350

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure there is enough water pressure in the system by checking the digital gauge.
  3. Restart the boiler using the reset button on the touch screen.

Parts commonly replaced

  • Circulation Pump
  • Flow Temperature Sensor (NTC)
  • Main Heat Exchanger (Cleaning)

Related codes

Full explanation for 204
204 O

Your boiler has stopped running because the water inside it has become hotter than the temperature you have requested.

High DIY-safe £100-280

What to check first

  1. Check that your radiator valves are open to allow water to circulate
  2. Ensure there is no air trapped in your radiators by bleeding them
  3. Check that the boiler pressure gauge is between 1 and 1.5 bar
  4. Reset the boiler to see if the fault clears

Parts commonly replaced

  • Circulation Pump
  • Temperature Sensor (NTC Thermistor)
  • Diverter Valve

Related codes

Full explanation for 204 O
208

Your boiler is currently set to a manual testing mode used by engineers to check emissions, which prevents it from operating normally.

Low DIY-safe

What to check first

  1. Locate the 'Chimney Sweep' button (icon looks like a brush) on the touch screen display.
  2. Press and hold the button for approximately 3 to 5 seconds.
  3. The display should return to the standard temperature screen once the mode is deactivated.

Related codes

Full explanation for 208
208 0

Your boiler is currently in a manual testing mode used by engineers to check emissions, which means it is running at a fixed output rather than following your thermostat.

Low DIY-safe

What to check first

  1. Locate the 'Exit' or 'Back' button on the boiler control panel.
  2. Press and hold the button for a few seconds to cancel the test mode.
  3. The display should return to the standard temperature or status screen.

Related codes

Full explanation for 208 0
214

Your boiler has detected an issue with the air fan system and has safely shut down to prevent the appliance from starting incorrectly.

High Engineer only £180-450

Parts commonly replaced

  • Fan Assembly
  • Main PCB
  • Wiring Harness
Full explanation for 214
224

Your boiler has shut down because a safety sensor has detected that it is getting far too hot, likely due to a blockage or a pump failure.

High Engineer only £120-£350

Parts commonly replaced

  • Overheat Thermostat
  • Circulating Pump
  • Heat Exchanger

Related codes

Full explanation for 224
Showing 41–50 of 163
224 V

Your boiler has switched itself off because it has detected it is getting too hot, usually caused by the water pressure being too low.

High DIY-safe £0-140

What to check first

  1. Check the pressure gauge on the front of the boiler or the digital display.
  2. Locate the filling link (usually a blue lever underneath the boiler or a white plastic key).
  3. Slowly top up the water pressure until it reaches between 1.0 and 1.5 bar.
  4. Press the 'Reset' button on the boiler display to clear the fault.

Parts commonly replaced

  • External Filling Loop
  • Overheat Thermostat
  • System Pump

Related codes

Full explanation for 224 V
227

Your boiler is failing to light the gas even though it is trying to, which prevents your heating and hot water from working.

High DIY-safe £120-350

What to check first

  1. Check if other gas appliances (like a hob) are working to ensure gas is reaching the property
  2. Check if your gas meter has credit (if using a pre-payment meter)
  3. Hold the 'Reset' button on the front of the boiler for 3 seconds

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
  • Ignition Lead

Related codes

Full explanation for 227
227 V

Your boiler is failing to light the flame properly, meaning you will not have any heating or hot water until the issue is resolved.

High DIY-safe £120-450

What to check first

  1. Check if your gas supply is working by testing other gas appliances like a hob
  2. Ensure your gas meter has credit if you use a pre-payment meter
  3. Press the Reset button on the boiler display panel once to attempt a restart

Parts commonly replaced

  • Flame Sensing Electrode
  • Ignition Lead
  • Gas Valve
  • Burner Control Unit (PCB)

Related codes

Full explanation for 227 V
228

Your boiler thinks a flame is burning even though it hasn't actually sparked or started, causing it to shut down for safety.

High Engineer only £120-£280

Parts commonly replaced

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

Related codes

Full explanation for 228
228 V

Your boiler thinks it can see a flame even though it hasn't started the ignition process yet, which prevents it from running for safety reasons.

High Engineer only £180-350

Parts commonly replaced

  • Ionisation electrode
  • Gas valve
  • Detection cable

Related codes

Full explanation for 228 V
229

Your boiler started to heat up but the flame went out unexpectedly, causing the system to shut down for safety.

High DIY-safe £100-£350

What to check first

  1. Check if other gas appliances (like a hob) are working to confirm gas supply
  2. Ensure your gas meter has credit if you use a pre-payment meter
  3. Check that the condensate pipe (the plastic pipe leading outside) isn't frozen if it is very cold

Parts commonly replaced

  • Ionisation Probe
  • Ignition Electrode
  • Gas Valve

Related codes

Full explanation for 229
232

Your boiler has been turned off by an external control, such as a smart thermostat, a safety switch, or a heating zone controller.

Medium DIY-safe £0-120

What to check first

  1. Check that your room thermostat is turned up higher than the current room temperature.
  2. Ensure your smart heating hub and internet router are both powered on and connected.
  3. Replace the batteries in your wireless room thermostat or wall controller.
  4. Check if a safety device, like a condensation pump, has overflowed and tripped the switch.

Parts commonly replaced

  • Thermostat batteries
  • Room thermostat
  • Condensate pump
  • Wiring center

Related codes

Full explanation for 232
233

Your boiler's computer has lost the ability to identify itself and requires a professional reset or part replacement.

High Engineer only £180-450

Parts commonly replaced

  • Boiler Identification Module (KIM)
  • Main PCB

Related codes

Full explanation for 233
234

Your boiler has detected an electrical problem with the component that controls the gas supply, meaning it cannot safely light the burner to provide heat or hot water.

High Engineer only £220-380

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • PCB

Related codes

Full explanation for 234
235

Your boiler's internal computer parts are having trouble communicating because they don't recognise each other's software versions.

High Engineer only £120-£450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Boiler Chip Card (KCM)

Related codes

Full explanation for 235
Showing 51–60 of 163
237

Your boiler's computer has detected an internal communication error and has shut down as a safety precaution.

High Engineer only £150-£450

Parts commonly replaced

  • Main PCB
  • Internal Wiring Harness
  • Control Unit

Related codes

Full explanation for 237
238

Your boiler's internal computer has encountered a critical error and can no longer communicate with the rest of the system.

High Engineer only £350-£650

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 238
242

Your boiler has experienced an internal electrical error that is preventing it from firing up to provide heating or hot water.

High Engineer only £180-£450

Parts commonly replaced

  • Flame sensing electrode
  • Ignition lead
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 242
244

Your boiler's internal computer has encountered a communication error or logic conflict, causing the system to stop working for safety.

High DIY-safe £180-450

What to check first

  1. Press the Reset button on the front control panel once
  2. Turn the power switch to the boiler off, wait 30 seconds, and turn it back on
  3. Ensure there are no external electrical interference sources near the boiler control panel

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Display Interface Module
  • Wiring Loom

Related codes

Full explanation for 244
245

Your boiler’s internal computer has encountered a critical communication error and can no longer process instructions.

High Engineer only £350-£550

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 245
249

Your boiler’s internal computer has encountered a communication error or internal glitch that is preventing it from running properly.

High DIY-safe £250-£550

What to check first

  1. Locate the Reset button on the front control panel
  2. Press and hold the Reset button for three seconds until the boiler restarts
  3. Wait up to 10 minutes for the boiler to complete its startup sequence

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
  • Display interface module

Related codes

Full explanation for 249
250

Your boiler's main internal computer has encountered a communication error and needs a reset to try and clear the glitch.

High DIY-safe £280-550

What to check first

  1. Locate the reset button on the boiler's front control panel
  2. Press and hold the reset button for five seconds
  3. Wait for the boiler to restart and check if the error code has cleared

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring harness

Related codes

Full explanation for 250
251

Your boiler's internal computer is experiencing a software or logic error, preventing it from processing information correctly.

High DIY-safe £180-450

What to check first

  1. Press the Reset button on the front control panel once.
  2. If the code persists, turn the boiler's power switch off for 30 seconds and then back on.
  3. Ensure there has not been a recent power cut or surge in the home.

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Harness

Related codes

Full explanation for 251
252

Your boiler’s internal computer has encountered a communication error or an internal glitch and cannot operate until it is reset or repaired.

High DIY-safe £250-£450

What to check first

  1. Locate the 'Reset' button on the boiler control panel
  2. Press and hold the button for 3 to 5 seconds
  3. Wait for the boiler to restart and monitor if the code clears

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 252
253

Your boiler's internal computer has encountered a software or hardware communication error, preventing it from starting up correctly.

High DIY-safe £350-£600

What to check first

  1. Press the 'Reset' button on the boiler control panel once
  2. Switch the main electrical power to the boiler off and back on again after 30 seconds
  3. Check if the error clears and the boiler restarts its ignition sequence

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Display Control Unit
  • Wiring Loom

Related codes

Full explanation for 253
Showing 61–70 of 163
254

Your boiler's internal computer brain is experiencing a critical communication error or software glitch that is preventing it from running.

High Engineer only £180-450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Display PCB
  • Wiring Harness

Related codes

Full explanation for 254
257

Your boiler's internal computer has encountered a software or communication error and cannot operate properly.

High DIY-safe £250-500

What to check first

  1. Locate the reset button on the front control panel.
  2. Press and hold the reset button for several seconds.
  3. Wait for the boiler to restart and monitor if the code clears.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 257
258

Your boiler's internal computer has encountered a software or hardware communication error and has stopped working to protect itself.

High Engineer only £250-£550

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Display Control Unit

Related codes

Full explanation for 258
259

Your boiler's internal computer has encountered a software or communication error and can no longer control the heating process.

High DIY-safe £250-450

What to check first

  1. Locate the reset button on the boiler's front control panel.
  2. Press and hold the reset button for three seconds until the display changes.
  3. Wait for the boiler to complete its restart sequence to see if the error clears.

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Display Control Unit

Related codes

Full explanation for 259
262

Your boiler's internal computer has encountered a communication error or a software fault and cannot operate correctly.

High DIY-safe £300-£650

What to check first

  1. Press the Reset button on the boiler's front display panel
  2. Turn off the power to the boiler at the fused spur switch, wait 30 seconds, and turn it back on
  3. Check if any recent electrical work in the home might have caused a power surge

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Display Key
  • Wiring Harness

Related codes

Full explanation for 262
263

Your boiler’s internal computer has encountered a software or hardware error and can no longer communicate with the rest of the system.

High Engineer only £250-£550

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wire Loom

Related codes

Full explanation for 263
265

Your boiler is temporarily pausing because it is producing more heat than your radiators or hot water system can currently use or circulate.

Low DIY-safe £0-120

What to check first

  1. Ensure at least two or three radiators have their thermostatic valves (TRVs) turned up to maximum.
  2. Check that all radiator valves are open and not stuck closed.
  3. Verify that your room thermostat is set to a temperature higher than the current room temperature.

Parts commonly replaced

  • None (Adjustment only)
  • Bypass Valve
  • Circulation Pump

Related codes

Full explanation for 265
268

Your boiler is performing a routine self-diagnostic test on its internal electrical switches and should return to normal operation shortly.

Low DIY-safe £0-80

What to check first

  1. Wait for 5-10 minutes for the automated test sequence to complete
  2. If the code persists, press the 'Reset' button on the front display panel once
  3. Ensure there is power to the boiler and no recent power cuts have occurred

Parts commonly replaced

  • No parts usually required
  • Printed Circuit Board (PCB) if test fails repeatedly

Related codes

Full explanation for 268
269

Your boiler is struggling to detect a flame when it tries to start, which means it cannot fire up to provide heating or hot water.

High DIY-safe £120-350

What to check first

  1. Check if other gas appliances, like a hob, are working to ensure a gas supply.
  2. Check that your gas pre-payment meter (if you have one) has credit.
  3. Press the Reset button on the boiler display panel and wait for it to restart.

Parts commonly replaced

  • Ionisation electrode
  • Ignition lead
  • Gas valve

Related codes

Full explanation for 269
273

Your boiler has paused its operation because it has been running continuously for 24 hours and needs to perform a brief internal safety check.

Low DIY-safe

What to check first

  1. Wait for several minutes as the boiler usually restarts itself automatically after the safety check.
  2. If the code persists, turn the power to the boiler off and back on again to reset the timer.
  3. Ensure your thermostat is not set to an unusually high temperature that prevents the boiler from ever reaching its target.

Related codes

Full explanation for 273
Showing 71–80 of 163
281

Your boiler's internal pump is unable to move water because it is jammed or contains trapped air, stopping your heating from working.

High DIY-safe £180-450

What to check first

  1. Check that your radiator valves are open
  2. Ensure the boiler pressure is between 1 and 1.5 bar on the front display
  3. Gently bleed your radiators to remove any trapped air
  4. Reset the boiler to see if the pump clears the blockage

Parts commonly replaced

  • Circulating Pump
  • Automatic Air Vent
  • Expansion Vessel

Related codes

Full explanation for 281
283

Your boiler is currently transitioning between modes or performing a safety check while the burner gets ready to fire up.

Low DIY-safe

What to check first

  1. Wait a few minutes for the code to clear automatically
  2. Check if there is a demand for heating or hot water
  3. Reset the boiler only if the code remains frozen for more than 5 minutes

Related codes

Full explanation for 283
284

Your boiler is struggling to deliver the correct mix of air and gas required to light the burner safely.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Electronic control board (PCB)
  • Wire harness

Related codes

Full explanation for 284
305

Your boiler is temporarily pausing the hot water production to prevent itself from overheating or cycling on and off too frequently.

Low DIY-safe

What to check first

  1. Wait up to 15 minutes for the anti-cycle timer to expire
  2. Ensure hot water taps are fully closed
  3. Check that the hot water temperature setting on the control panel is not set excessively high

Related codes

Full explanation for 305
305 0

Your boiler has temporarily stopped heating water to prevent it from overheating and will automatically restart once it has cooled down.

Low DIY-safe

What to check first

  1. Wait up to 15 minutes for the anti-cycle timer to finish
  2. Ensure your hot water taps are fully closed
  3. Check that the hot water temperature setting on the boiler display is not set unnecessarily high

Related codes

Full explanation for 305 0
306

Your boiler is still detecting a flame even though it has tried to shut off the gas supply, which is a safety conflict.

Emergency Engineer only £180-450

Parts commonly replaced

  • Gas Valve
  • Ionisation Electrode
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 306
306 V

Your boiler is still detecting a flame even after it has tried to shut off the gas, which is a safety conflict that requires a professional inspection.

Emergency Engineer only £220-£450

Parts commonly replaced

  • Gas valve
  • Ionisation electrode
  • Control PCB

Related codes

Full explanation for 306 V
357

Your boiler is currently running a self-cleaning sequence to remove air bubbles from the internal heating circuit, which usually happens when it is first turned on or after maintenance.

Low DIY-safe

What to check first

  1. Wait approximately 10 to 15 minutes for the automated program to finish
  2. Ensure your radiator valves are open to help move air through the system
  3. Once the countdown or message disappears, the boiler should return to normal operation automatically

Related codes

Full explanation for 357
358

Your boiler is performing a routine self-cleaning cycle to prevent internal parts from getting stuck during periods of inactivity.

Low DIY-safe

What to check first

  1. Wait for 30 to 60 seconds for the operation to complete
  2. Ensure the boiler power remains switched on
  3. Monitor the display to confirm the code clears automatically
Full explanation for 358
360

Your boiler’s internal computer has encountered a memory error or is having trouble communicating with its own control board.

High Engineer only £250-£450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Codework plug

Related codes

Full explanation for 360
Showing 81–90 of 163
360 V

Your boiler's internal computer has lost communication with its identification chip or the chip installed is the wrong model for this unit.

High Engineer only £120-280

Parts commonly replaced

  • HCM Code Plug
  • Boiler Control Board (PCB)

Related codes

Full explanation for 360 V
362

Your boiler has developed a serious internal electronic failure that means it can no longer recognize its own control system.

High Engineer only £280-550

Parts commonly replaced

  • Boiler Identification Module (KIM)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 362
363

Your boiler has encountered an internal communication error between its main electronic control boards, meaning it cannot currently function or heat your home.

High DIY-safe £280-550

What to check first

  1. Locate the power switch or fused spur for the boiler
  2. Turn the power off, wait for 30 seconds, and turn it back on
  3. Press the 'Reset' button on the boiler display once it restarts

Parts commonly replaced

  • Primary PCB (Main Circuit Board)
  • Display PCB Hub
  • Wiring Loom

Related codes

Full explanation for 363
604

Your boiler has stopped working because its internal computer has detected a communication error with the burner control system.

High Engineer only £280-£550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness
Full explanation for 604
815

Your boiler is receiving incorrect temperature readings from a secondary part of your heating system, which may be preventing your home from heating up efficiently.

Medium Engineer only £120-£190

Parts commonly replaced

  • Low loss header temperature sensor (NTC)
  • Wiring harness
Full explanation for 815
815 W/B

Your boiler's temperature sensors are receiving conflicting or incorrect readings, causing the system to stop working correctly to protect itself.

High Engineer only £120-190

Parts commonly replaced

  • Low loss header temperature sensor
  • NTC thermistor
  • Wiring harness
Full explanation for 815 W/B
1010

Your boiler's internal computer system has lost communication with its external controls or smart thermostat, meaning it cannot receive instructions to turn on.

High DIY-safe £90-250

What to check first

  1. Check that your smart thermostat gateway or hub is plugged in and powered on
  2. Ensure your Wi-Fi router is working correctly
  3. Turn the boiler power off and back on at the fused spur switch to reboot the system

Parts commonly replaced

  • EMS Bus wiring
  • Worcester Bosch EasyControl Adapter
  • Internal PCB

Related codes

Full explanation for 1010
1010 O

Your boiler's internal computer has lost its connection to its main controls, meaning it cannot receive the instructions it needs to provide heating or hot water.

High Engineer only £100-£250

Parts commonly replaced

  • EMS Bus Wiring Harness
  • PCB Fuse
  • Main Control Board (PCB)
Full explanation for 1010 O
1013

Your boiler has reached its maximum power limit while trying to heat your water, and it has stopped for a short time to prevent overheating.

Medium DIY-safe £100-250

What to check first

  1. Check that all your radiator valves are fully open
  2. Ensure your system pressure is topped up to between 1.0 and 1.5 bar
  3. Press the 'Reset' button on the front of the screen to clear the temporary lockout

Parts commonly replaced

  • Circulation pump
  • Main heat exchanger (flushing)
  • Flow and return sensors

Related codes

Full explanation for 1013
1017

Your boiler has stopped working because the water pressure inside the system has dropped below the minimum level required to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the internal or external filling link (often blue levers or a braided hose under the boiler).
  2. Slowly open the valves until you hear water entering the system.
  3. Watch the digital display or pressure gauge until it reaches between 1.0 and 1.5 bar, then close the valves completely.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel
Full explanation for 1017
Showing 91–100 of 163
1017 W

Your boiler has stopped working because the water pressure is too low and needs to be topped up.

High DIY-safe £0-180

What to check first

  1. Locate the integrated filling link (blue levers) or the external filling loop underneath the boiler
  2. Slowly open the valves until you hear water moving and watch the digital display or pressure gauge
  3. Close the valves firmly once the pressure reaches between 1.0 and 1.5 bar

Parts commonly replaced

  • Pressure sensor
  • Auto air vent

Related codes

Full explanation for 1017 W
1018

Your boiler is simply reminding you that its scheduled annual service is now due to ensure it continues running safely and efficiently.

Low Engineer only £80-120

Parts commonly replaced

  • Service kit (seals and electrodes)
  • Burner gasket

Related codes

Full explanation for 1018
1019

Your boiler's computer cannot communicate properly with the internal pump, usually because it doesn't recognize the specific model or there is a software mismatch.

High Engineer only £250-£450

Parts commonly replaced

  • Circulation Pump
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 1019
1021

Your boiler is struggling to accurately measure the temperature of your hot water, which usually means your taps aren't getting hot enough or stay cold.

High Engineer only £110-180

Parts commonly replaced

  • Cylinder temperature sensor (NTC thermistor)
  • DHW temperature sensor
  • Wiring harness

Related codes

Full explanation for 1021
1021 B

Your boiler is unable to provide hot water because it cannot accurately measure how hot the water is.

High Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) Temperature Sensor
  • Wiring harness connector

Related codes

Full explanation for 1021 B
1022 B

Your boiler is unable to read the temperature of your hot water tank, which means your taps and showers may not get hot.

High Engineer only £90-180

Parts commonly replaced

  • Hot water storage temperature sensor (NTC)
  • Sensor wiring harness

Related codes

Full explanation for 1022 B
1023

Your boiler has been running for a long continuous period and needs to be reset to ensure its internal monitors can perform a safety self-check.

Low DIY-safe

What to check first

  1. Locate the 'Reset' button on the boiler control panel.
  2. Press the reset button once.
  3. The boiler should restart and resume normal operation.

Related codes

Full explanation for 1023
1025

Your boiler's internal thermometer that measures the water returning from your radiators has developed a fault and can no longer read the temperature correctly.

High Engineer only £120-190

Parts commonly replaced

  • Return Water Temperature Sensor (NTC Thermistor)
  • Wiring Harness
Full explanation for 1025
1037

Your boiler has lost contact with its outdoor thermometer, so it is running at a pre-set steady temperature to keep your home warm while it ignores external weather changes.

Low Engineer only £90-160

Parts commonly replaced

  • Outdoor weather compensation sensor
  • Sensor wiring

Related codes

Full explanation for 1037
1037 W

Your boiler has lost connection with its outdoor thermometer, meaning it might not adjust its heating efficiently based on the weather outside.

Low Engineer only £90-160

Parts commonly replaced

  • Outdoor weather compensation sensor
  • Sensor wiring
Full explanation for 1037 W
Showing 101–110 of 163
1065

Your boiler has detected an issue with the sensor that monitors internal water pressure, meaning it cannot confirm if there is enough water to operate safely.

High Engineer only £140-£220

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness

Related codes

Full explanation for 1065
1065 B

Your boiler's internal water pressure sensor is not communicating properly with the control board, preventing the system from operating safely.

High Engineer only £140-£220

Parts commonly replaced

  • Water Pressure Sensor
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for 1065 B
1068

Your boiler's internal sensor system is confused about the air quality or external temperature, which may hinder its efficiency or ability to run.

Medium Engineer only £140-280

Parts commonly replaced

  • Lambda sensor
  • Outside temperature sensor
  • Wiring harness

Related codes

Full explanation for 1068
1068 W

Your boiler is struggling to work out how hard it needs to fire because the sensor that monitors the weather outside has stopped sending a signal.

Low Engineer only £90-160

Parts commonly replaced

  • Outside weather compensation sensor
  • Sensor wiring
Full explanation for 1068 W
1070

Your boiler is simply reminding you that its annual service is due soon to keep it running safely and efficiently.

Low Engineer only £80-£130

Parts commonly replaced

  • Service kit (seals and gaskets)
  • Spark electrode

Related codes

Full explanation for 1070
1071

Your boiler is reminding you that its annual service is now due to keep it running safely and efficiently.

Low Engineer only £80-130

Parts commonly replaced

  • Service kit (seals/washers)
  • Electrode (if worn)

Related codes

Full explanation for 1071
1072

Your boiler is simply reminding you that it is time for its routine annual service to keep it running safely and efficiently.

Low Engineer only £80-130

Parts commonly replaced

  • Service kit (seals and electrodes)

Related codes

Full explanation for 1072
1073 W

Your boiler has detected an electrical fault with its main temperature sensor, which means it cannot safely monitor how hot the water is and has stopped working as a precaution.

High Engineer only £90-160

Parts commonly replaced

  • Flow temperature NTC sensor
  • Connecting wiring harness

Related codes

Full explanation for 1073 W
1074 W

Your boiler has lost communication with its internal thermometer, meaning it cannot safely monitor the temperature of the water circulating through your radiators.

High Engineer only £90-160

Parts commonly replaced

  • Flow temperature NTC sensor
  • Wiring harness connector

Related codes

Full explanation for 1074 W
1075

Your boiler has stopped working because it thinks the internal heat sensor is damaged or has an electrical fault, preventing it from monitoring temperature safely.

High Engineer only £120-190

Parts commonly replaced

  • Heat exchanger temperature sensor (NTC thermistor)
  • Wiring harness connector

Related codes

Full explanation for 1075
Showing 111–120 of 163
1075 W

Your boiler has detected an electrical fault with an internal temperature sensor, preventing the system from monitoring heat levels safely.

High Engineer only £120-£190

Parts commonly replaced

  • Flow temperature sensor
  • NTC sensor wiring harness

Related codes

Full explanation for 1075 W
1076

Your boiler has stopped working because it can no longer communicate with the sensor that monitors the temperature of the main heating unit.

High Engineer only £100-£220

Parts commonly replaced

  • Primary heat exchanger NTC sensor
  • Sensor wiring harness

Related codes

Full explanation for 1076
1076 W

Your boiler has lost communication with its internal temperature sensor, meaning it cannot monitor heat levels and has shut down as a safety precaution.

High Engineer only £140-£260

Parts commonly replaced

  • NTC Temperature Sensor
  • Sensor Wiring Harness
  • Main PCB (Control Unit)

Related codes

Full explanation for 1076 W
2085

Your boiler has encountered an internal software or communication error that is preventing it from heating your home.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 2085
2908

Your boiler's internal computer has encountered a communication error or internal electronic glitch that is preventing it from working correctly.

High DIY-safe £250-£550

What to check first

  1. Press the Reset button on the front of the boiler display.
  2. If the code persists, turn the main power supply to the boiler off at the fused spur switch, wait 30 seconds, and turn it back on.
  3. If the code returns immediately, you will need to book a Gas Safe registered engineer.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 2908
2910

Your boiler is struggling to safely expel exhaust gases, which has caused the system to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Flue fan
  • Air pressure switch
  • Flue seals

Related codes

Full explanation for 2910
2914

Your boiler's internal computer has detected a general electrical communication error and is unable to operate correctly.

High Engineer only £250-550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 2914
2915

Your boiler's main internal computer has encountered a memory or communication error, preventing the system from running safely.

High Engineer only £250-550

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • HMI (Display Interface Panel)

Related codes

Full explanation for 2915
2916

Your boiler has detected an internal electrical communication error, meaning it cannot properly coordinate its functions to provide heat and hot water.

High Engineer only £250-£650

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Harness
  • Display Module

Related codes

Full explanation for 2916
2920

Your boiler has detected a problem with how it tracks its own flame, causing it to shut down for safety purposes.

High Engineer only £120-350

Parts commonly replaced

  • Ionisation electrode
  • Flame sensing lead
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 2920
Showing 121–130 of 163
2920 V

Your boiler has stopped working because it cannot confirm that the flame is properly lit, causing the system to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Ionisation Electrode
  • Flame Sensing Lead
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 2920 V
2923

Your boiler has detected an internal electrical communication error, which means it has stopped running to prevent damage to its electronic components.

High DIY-safe £280-550

What to check first

  1. Press the 'Reset' button on the front display panel and hold for three seconds.
  2. Wait up to 10 minutes for the boiler to complete its restart sequence.
  3. Ensure your household electricity supply is stable and you have not recently had a power cut.

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 2923
2924

Your boiler has detected an internal electrical problem that is preventing it from starting up safely.

High Engineer only £250-£550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 2924
2924 V

Your boiler has detected an internal electrical communication error between the control board and the gas valve, preventing the burner from lighting safely.

High Engineer only £250-£450

Parts commonly replaced

  • Gas Valve
  • PCB (Internal Control Board)

Related codes

Full explanation for 2924 V
2925

Your boiler has experienced an internal electrical error that has caused it to stop working for safety.

High DIY-safe £250-550

What to check first

  1. Press the 'Reset' button on the front control panel once.
  2. Wait up to 10 minutes to see if the boiler restarts normally.
  3. If the code persists or returns immediately, do not attempt further repairs and contact a Gas Safe engineer.

Parts commonly replaced

  • Internal Wiring Harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 2925
2925 V

Your boiler has stopped working because it cannot properly communicate with the internal valve that controls the gas flow.

High Engineer only £180-£350

Parts commonly replaced

  • Modulating gas valve
  • Wiring harness
  • Main PCB (Control board)

Related codes

Full explanation for 2925 V
2926

Your boiler's internal computer has detected a general electrical communication error and has shut down as a safety precaution.

High Engineer only £180-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 2926
2927 B

Your boiler has lost its flame while running and has shut down for safety because it can no longer detect the fire needed to heat your water.

High Engineer only £120-£350

Parts commonly replaced

  • Ionisation Electrode
  • Gas Valve
  • Burner Control Unit
  • Ignition Lead

Related codes

Full explanation for 2927 B
2928

Your boiler's internal computer has encountered a software or hardware error that is preventing it from running properly.

High DIY-safe £180-450

What to check first

  1. Locate the Reset button on the boiler's front control panel.
  2. Press and hold Reset for three seconds.
  3. Wait for the boiler to complete its restart sequence to see if the error clears.

Parts commonly replaced

  • Main Heatronic Circuit Board (PCB)
  • Display Interface Module

Related codes

Full explanation for 2928
2931

Your boiler's main internal computer has encountered a processing error and cannot communicate correctly with the system.

High DIY-safe £350-£650

What to check first

  1. Press the 'Reset' button on the front display once
  2. Switch the main electrical power to the boiler off at the fused spur switch
  3. Wait 60 seconds and switch the power back on to see if the error clears

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Display Control Unit
Full explanation for 2931
Showing 131–140 of 163
2940

Your boiler has detected an internal communication error or hardware fault within its main control system, preventing it from firing up safely.

High Engineer only £250-550

Parts commonly replaced

  • Burner Control Unit
  • Main PCB
  • Wiring Harness

Related codes

Full explanation for 2940
2946

Your boiler's computer memory chip is not being recognised or is mismatched, which prevents the system from starting up.

High Engineer only £120-280

Parts commonly replaced

  • HCM code plug
  • PCB (Control board)

Related codes

Full explanation for 2946
2946 V

Your boiler's internal computer chip is either missing or has failed, meaning the system doesn't know which specific model it's supposed to be.

High Engineer only £120-£220

Parts commonly replaced

  • Coding Plug (KCM)
  • Main PCB
Full explanation for 2946 V
2948

Your boiler is struggling to stay lit when it is running at its lowest power level, often causing it to shut down for safety.

High Engineer only £120-280

Parts commonly replaced

  • Ionisation Probe
  • Gas Valve
  • Electrode Set

Related codes

Full explanation for 2948
2948 B

Your boiler is struggling to keep its flame lit during operation, which is causing it to stop and restart frequently.

High Engineer only £120-300

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Ignition lead

Related codes

Full explanation for 2948 B
2949

Your boiler is failing to detect a flame when it tries to work at a high power level, causing it to shut down for safety.

High Engineer only £120-£350

Parts commonly replaced

  • Gas valve
  • Ionisation electrode
  • Burner gasket
  • Fan assembly

Related codes

Full explanation for 2949
2950

Your boiler has tried to start up but cannot detect a flame, meaning it cannot provide heating or hot water.

High DIY-safe £100-£350

What to check first

  1. Check if other gas appliances (like a hob) are working to ensure gas is reaching the property
  2. Check that your prepaid gas meter has credit
  3. Try resetting the boiler using the reset button on the touchscreen

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
  • Ignition Lead

Related codes

Full explanation for 2950
2950 B

Your boiler is trying to light itself but cannot detect a flame, meaning your heating and hot water will likely stop working.

High Engineer only £120-350

Parts commonly replaced

  • Flame sensing electrode
  • Ignition lead
  • Gas valve
  • Spark electrode

Related codes

Full explanation for 2950 B
2951

Your boiler is struggling to keep its burner lit and has turned itself off for safety after several failed attempts to maintain a steady flame.

High DIY-safe £100-280

What to check first

  1. Check that your gas prepayment meter has credit (if applicable)
  2. Verify that other gas appliances, like a hob, are working correctly to ensure gas supply
  3. Press the 'Reset' button on the boiler display panel once
  4. Check that the condensate pipe outside is not frozen or blocked

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
  • Condensate Trap

Related codes

Full explanation for 2951
2952

Your boiler has detected an internal error while trying to check if the flame is burning safely, causing the system to shut down for safety.

High Engineer only £180-450

Parts commonly replaced

  • Ionisation Electrode
  • Ignition Lead
  • Circuit Board (PCB)

Related codes

Full explanation for 2952
Showing 141–150 of 163
2955

Your boiler’s internal computer has been given instructions that it doesn't recognize or that don't match how the unit is physically built.

High Engineer only £80-160

Parts commonly replaced

  • None (Software reconfiguration required)
  • PCB (if memory is corrupted)

Related codes

Full explanation for 2955
2956

Your boiler has detected that a specific accessory or additional part has been connected and needs to be set up through the control panel.

Low DIY-safe £0-80

What to check first

  1. Navigate to the 'Settings' menu on the boiler screen
  2. Select 'Hydraulic Configuration' and confirm the installed setup
  3. Press and hold 'Reset' to clear the message once the settings are saved

Related codes

Full explanation for 2956
2957

Your boiler has detected an internal electrical communication error, which means it has stopped working as a safety precaution.

High Engineer only £280-550

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wiring Harness
Full explanation for 2957
2961

Your boiler has stopped working because the internal computer cannot communicate with the fan that safely clears away exhaust fumes.

High Engineer only £250-£450

Parts commonly replaced

  • Fan motor
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 2961
2962

Your boiler has stopped working because the internal computer cannot communicate with the fan that safely clears away used gases.

High Engineer only £250-450

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 2962
2963

Your boiler has detected that the sensors monitoring its internal temperature are giving incorrect readings or have failed, causing the system to shut down for safety.

High Engineer only £140-£240

Parts commonly replaced

  • Heat exchanger temperature sensor
  • Flow temperature sensor
  • Wiring harness

Related codes

Full explanation for 2963
2963 B

Your boiler has detected an unusual temperature reading because a sensor or its wiring is not communicating correctly with the main control unit.

High Engineer only £90-180

Parts commonly replaced

  • Temperature sensor (NTC thermistor)
  • Wiring harness
  • Heat exchanger sensor clip

Related codes

Full explanation for 2963 B
2964 B

Your boiler has detected that water is not moving through its internal heating unit fast enough, which can cause the system to overheat and shut down.

High DIY-safe £120-£450

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the front display
  2. Ensure all radiator valves are fully open to allow water to circulate
  3. Inspect the magnetic system filter, if fitted, to see if it needs cleaning

Parts commonly replaced

  • Internal pump
  • Plate heat exchanger
  • Flow temperature sensor

Related codes

Full explanation for 2964 B
2965

Your boiler has sensed that the water inside is getting much hotter than it should be and has shut down as a safety precaution.

High DIY-safe £120-280

What to check first

  1. Ensure all radiator valves (TRVs) are turned to the highest setting
  2. Check that the boiler pressure gauge is between 1 and 1.5 bar
  3. Reset the boiler using the display panel to see if the fault clears

Parts commonly replaced

  • Circulation Pump
  • Flow Temperature Sensor (NTC)
  • Main Heat Exchanger (Flushing)

Related codes

Full explanation for 2965
2965 B

Your boiler has shut down because the water inside is getting much hotter than it should be, which is often caused by a blockage or a pump failure preventing the heat from moving away.

High DIY-safe £120-£350

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure your boiler pressure gauge is between 1 and 1.5 bar; top up if necessary.
  3. Check if any external bypass valves or magnetic system filters are blocked.

Parts commonly replaced

  • Circulation Pump
  • Flow Temperature Sensor (NTC)
  • Main Heat Exchanger (Flushing required)

Related codes

Full explanation for 2965 B
Showing 151–160 of 163
2966

Your boiler is overheating too quickly because water isn't moving through the system fast enough.

High DIY-safe £120-£350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the system pressure is between 1.0 and 1.5 bar
  3. Bleed your radiators to remove any trapped air

Parts commonly replaced

  • Circulating pump
  • Main heat exchanger (flushing required)
  • Temperature sensors

Related codes

Full explanation for 2966
2966 B

Your boiler is heating up too quickly and has shut down to prevent damage, usually because water isn't flowing through the system fast enough.

High DIY-safe £120-£350

What to check first

  1. Check that your radiator valves (TRVs) are fully open and not stuck.
  2. Ensure the blue filling loop handle is closed and the system pressure is between 1 and 1.5 bar.
  3. Restart the boiler using the reset button on the display panel.

Parts commonly replaced

  • Circulating pump
  • Main heat exchanger (flushing)
  • Flow/Return thermistors

Related codes

Full explanation for 2966 B
2967 B

Your boiler has detected that water is heating up too quickly or unevenly, causing it to shut down for safety to prevent overheating.

High DIY-safe £120-350

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the front display
  2. Ensure all radiator valves are fully open to allow water to flow
  3. Check for any visible leaks around the boiler or radiators

Parts commonly replaced

  • Circulation Pump
  • Flow Temperature Sensor
  • Heat Exchanger (Flush/Clean)

Related codes

Full explanation for 2967 B
2968

Your boiler has detected that the water pressure is too low and it is currently trying to top itself up automatically.

Low DIY-safe £0-120

What to check first

  1. Wait a few minutes to see if the 'Intelligent Filling System' completes the top-up automatically.
  2. If it does not stop, check the display for a prompt to manual override the filling valve.
  3. Check visible pipework and radiators for any signs of water leaks.

Parts commonly replaced

  • None (Software notification)
  • Automatic Filling Link (if faulty)

Related codes

Full explanation for 2968
2969

Your boiler's automatic filling system has topped up the water pressure too many times in a short period, suggesting there may be a leak in your heating system.

High Engineer only £100-350

Parts commonly replaced

  • Automatic filling valve
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for 2969
2970

Your boiler has detected that the water pressure in your heating system is falling much faster than normal, which usually indicates a significant leak or a fault with the pressure sensor.

High DIY-safe £90-250

What to check first

  1. Check all visible radiators and pipes for signs of water leaks
  2. Top up the system pressure using the internal filling link to between 1 and 1.5 bar
  3. Monitor the pressure gauge to see if it drops rapidly again after refilling

Parts commonly replaced

  • Pressure Sensor
  • Expansion Vessel
  • PRV (Pressure Relief Valve)

Related codes

Full explanation for 2970
2970 B

Your boiler has detected that the water pressure in your radiators is falling much faster than expected, which could indicate a significant leak.

High DIY-safe £100-350

What to check first

  1. Check all visible radiator valves and pipework for signs of water leaking
  2. Top up the system pressure to between 1 and 1.5 bar using the internal filling link
  3. Restart the boiler to see if the code clears and the pressure remains stable

Parts commonly replaced

  • Expansion Vessel
  • Pressure Relief Valve
  • Auto Air Vent

Related codes

Full explanation for 2970 B
2971

Your boiler has detected that the water pressure in the system has dropped below the minimum level required to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the integrated filling link handle underneath the boiler (on some models) or the external braided filling loop.
  2. Slowly pull the lever or open the valves to allow water into the system while watching the digital display or pressure gauge.
  3. Close the valves firmly once the pressure reaches 1.5 bar and the fault code disappears.

Parts commonly replaced

  • Intelligent Filling Link
  • Expansion Vessel
  • Pressure Sensor

Related codes

Full explanation for 2971
2971 B

Your boiler has detected that the water pressure in your heating system is too low to operate safely and effectively.

High DIY-safe £0-180

What to check first

  1. Check the pressure gauge on the front of the boiler; it will likely be in the red zone.
  2. Locate the filling link (either a built-in lever or a flexible silver hose) and slowly turn it to add water.
  3. Monitor the gauge and stop once it reaches between 1 and 1.5 bar, then ensure the filling link is fully closed.

Parts commonly replaced

  • External Filling Link
  • Water Pressure Sensor
  • Pressure Sensor Wiring Harness

Related codes

Full explanation for 2971 B
2972

Your boiler has detected that the electricity supply coming from your home's mains or the local grid is too low for it to operate safely.

High Engineer only £100-£350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Voltage Regulator
  • Wiring Harness

Related codes

Full explanation for 2972
Showing 161–163 of 163
A-A5

Your boiler has detected that the water temperature has risen too quickly or reached an unusually high level, causing it to shut down to prevent overheating.

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open to allow water to flow.
  2. Ensure the system pressure gauge is between 1.0 and 1.5 bar.
  3. Try resetting the boiler via the display panel to see if the fault clears.

Parts commonly replaced

  • Circulating pump
  • Flow temperature sensor (NTC thermistor)
  • Main heat exchanger (flushing/cleaning)

Related codes

Full explanation for A-A5
A-b2

Your boiler has detected an issue with how quickly hot water is moving through the system, which may result in inconsistent water temperatures.

Medium Engineer only £90-180

Parts commonly replaced

  • DHW Flow Turbine
  • Flow Sensor Board
  • Heat Exchanger

Related codes

Full explanation for A-b2
A-b4

Your boiler has detected an issue with the sensor that monitors the temperature of the hot water leaving the unit, which may result in inconsistent water temperatures.

Medium Engineer only £120-£220

Parts commonly replaced

  • Domestic Hot Water (DHW) Temperature Sensor
  • NTC Thermistor
  • Wiring Harness

Related codes

Full explanation for A-b4