Your boiler is displaying a status report of the most recent error it encountered, rather than a single specific active problem.
Worcester Bosch Ri 25 HE Fault codes & diagnostics
35 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar i Regular
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify.All 35 documented codes
Tap any card for details
Your boiler is currently operating normally and does not have an active fault; if there was a previous issue, this code is simply showing it has been resolved.
Your boiler is currently running through its normal internal start-up or status checks and is not reporting a specific fault at this moment.
Your boiler is simply taking a short, programmed break to prevent excessive wear and tear before it restarts your heating.
2.5 Your boiler has detected that the water inside the unit is getting too hot and has automatically shut down to prevent damage.
Your boiler has detected that the water inside the unit is getting too hot and has automatically shut down to prevent damage.
Parts commonly replaced
- NTC Temperature Sensor
- Primary Heat Exchanger
- Pump
Related codes
2.6 Your boiler is struggling to control exactly how much heat it produces, causing it to cycle on and off more frequently than it should.
Your boiler is struggling to control exactly how much heat it produces, causing it to cycle on and off more frequently than it should.
Parts commonly replaced
- NTC sensor
- Printed Circuit Board
- Main heat exchanger
Your boiler is currently operating at its maximum heating capacity and is functioning normally, rather than indicating a fault.
5.2 Your boiler's main control computer is struggling to communicate or process information correctly, which has caused it to stop heating your home as a safety precaution.
Your boiler's main control computer is struggling to communicate or process information correctly, which has caused it to stop heating your home as a safety precaution.
Parts commonly replaced
- Gas Fire Assembly (GFA) unit
- Printed Circuit Board (PCB)
Related codes
6.8 Your boiler is struggling to reach or maintain the correct temperature because it has been running in its hot water cycle for too long, suggesting it cannot satisfy the thermostat's demand.
Your boiler is struggling to reach or maintain the correct temperature because it has been running in its hot water cycle for too long, suggesting it cannot satisfy the thermostat's demand.
Parts commonly replaced
- NTC Temperature Sensor
- Diverter Valve
- Domestic Hot Water Thermistor
9.3 Your boiler has detected an internal computer error that prevents it from starting up correctly.
Your boiler has detected an internal computer error that prevents it from starting up correctly.
Parts commonly replaced
- Gas Fire Automator (GFA)
- Main PCB
A1 Your boiler has detected that the water pump is not moving water correctly, which often happens because there is air trapped in the system or the pressure is too low.
Your boiler has detected that the water pump is not moving water correctly, which often happens because there is air trapped in the system or the pressure is too low.
What to check first
- Check your boiler's pressure gauge and ensure it reads between 1 and 1.5 bar
- If the pressure is below 1 bar, use the external filling loop to top up the system
- Bleed your radiators to remove any trapped air that might be preventing water circulation
Parts commonly replaced
- Central heating pump
- Pressure relief valve
- Expansion vessel
A5 Your boiler is struggling to accurately detect the temperature of the water used for your heating and hot water, which may cause it to stop working correctly as a precaution.
Your boiler is struggling to accurately detect the temperature of the water used for your heating and hot water, which may cause it to stop working correctly as a precaution.
Parts commonly replaced
- NTC temperature sensor
- Wiring harness
A7 Your boiler is struggling to accurately detect the temperature of the water being used, which will likely prevent you from having hot water until it is fixed.
Your boiler is struggling to accurately detect the temperature of the water being used, which will likely prevent you from having hot water until it is fixed.
Parts commonly replaced
- NTC Temperature Sensor
Related codes
A8 Your boiler's electronic brains are struggling to talk to each other, so the system has shut down to prevent incorrect operation.
Your boiler's electronic brains are struggling to talk to each other, so the system has shut down to prevent incorrect operation.
Parts commonly replaced
- Printed circuit board (PCB)
- Wiring harness
Related codes
AC Your boiler's internal computer is unable to communicate with its control panel, meaning the unit cannot safely start or regulate your heating and hot water.
Your boiler's internal computer is unable to communicate with its control panel, meaning the unit cannot safely start or regulate your heating and hot water.
Parts commonly replaced
- Main electronic control board
- Wiring harness
Related codes
Ad Your boiler has detected that the water temperature has risen too quickly, leading it to shut down for safety to prevent overheating.
Your boiler has detected that the water temperature has risen too quickly, leading it to shut down for safety to prevent overheating.
Parts commonly replaced
- NTC Sensor
- Heat Exchanger
- Pump
Related codes
b1 Your boiler's internal control unit is struggling to recognise a crucial electrical connection, which is preventing the system from starting up.
Your boiler's internal control unit is struggling to recognise a crucial electrical connection, which is preventing the system from starting up.
Parts commonly replaced
- Keyed plug
- PCB (Printed Circuit Board)
- Wiring harness
Related codes
C1 Your boiler is struggling to push air through the system to burn fuel safely, so it has stopped working to protect itself.
Your boiler is struggling to push air through the system to burn fuel safely, so it has stopped working to protect itself.
Parts commonly replaced
- Fan assembly
- Air pressure switch
- Wiring harness
- Printed Circuit Board
Related codes
C4 Your boiler's internal fan is stuck running continuously, which prevents the system from starting up correctly or shutting down as it should.
Your boiler's internal fan is stuck running continuously, which prevents the system from starting up correctly or shutting down as it should.
Parts commonly replaced
- Fan assembly
- Printed Circuit Board (PCB)
Related codes
C6 Your boiler has detected that the internal fan responsible for moving air and burnt gases is spinning faster than it should, causing the system to stop working for safety reasons.
Your boiler has detected that the internal fan responsible for moving air and burnt gases is spinning faster than it should, causing the system to stop working for safety reasons.
Parts commonly replaced
- Fan assembly
- Printed Circuit Board (PCB)
Related codes
d1 Your boiler has stopped working because it is unable to accurately measure the temperature of the water returning to it, so it has shut down as a precaution.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water returning to it, so it has shut down as a precaution.
Parts commonly replaced
- Return temperature sensor
- Wiring harness
Related codes
d3 Your boiler has automatically shut down because an external safety device, typically linked to your underfloor heating, has detected that the water temperature is too high.
Your boiler has automatically shut down because an external safety device, typically linked to your underfloor heating, has detected that the water temperature is too high.
Parts commonly replaced
- External temperature limit thermostat
- Underfloor heating pump
- Mixing valve
Related codes
E0 Your boiler's main computer chip has encountered an internal error and cannot communicate properly to start the heating process.
Your boiler's main computer chip has encountered an internal error and cannot communicate properly to start the heating process.
Parts commonly replaced
- Main PCB
Related codes
E2 Your boiler has lost the ability to accurately measure the temperature of the water flowing through it, so it has shut down as a precaution to prevent overheating.
Your boiler has lost the ability to accurately measure the temperature of the water flowing through it, so it has shut down as a precaution to prevent overheating.
Parts commonly replaced
- NTC Temperature Sensor
- Wiring Harness
Related codes
E9 Your boiler has detected that it is dangerously overheating and has automatically shut itself down to prevent internal damage.
Your boiler has detected that it is dangerously overheating and has automatically shut itself down to prevent internal damage.
Parts commonly replaced
- Pump
- NTC thermistor
- Primary heat exchanger
- PCB
Related codes
EA Your boiler is failing to light the internal flame, which means it cannot provide you with any heating or hot water.
Your boiler is failing to light the internal flame, which means it cannot provide you with any heating or hot water.
Parts commonly replaced
- Ignition electrode
- Gas valve
- Printed Circuit Board
Related codes
F0 Your boiler has detected an internal software or electronic communication error that prevents it from starting up safely.
Your boiler has detected an internal software or electronic communication error that prevents it from starting up safely.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Wiring harness
Related codes
F7 Your boiler is detects a flame when it should be turned off, which is a safety concern that requires an immediate professional inspection.
Your boiler is detects a flame when it should be turned off, which is a safety concern that requires an immediate professional inspection.
Parts commonly replaced
- Gas valve
- Printed Circuit Board (PCB)
- Flame detection electrode
Related codes
FA Your boiler has detected that a flame is still burning inside even though it has commanded the gas supply to turn off, which is a potential safety concern.
Your boiler has detected that a flame is still burning inside even though it has commanded the gas supply to turn off, which is a potential safety concern.
Parts commonly replaced
- Gas valve
- Printed Circuit Board (PCB)
- Flame rectification electrode
Related codes
FC Your boiler's electronic control system is failing to communicate with the display screen, meaning the unit cannot show status information or process commands.
Your boiler's electronic control system is failing to communicate with the display screen, meaning the unit cannot show status information or process commands.
Parts commonly replaced
- Main PCB
- Display interface cable
- User control unit
Related codes
Fd Your boiler has entered a temporary safety mode because the reset button was held down for too long, essentially causing a software lock.
Your boiler has entered a temporary safety mode because the reset button was held down for too long, essentially causing a software lock.
What to check first
- Switch the boiler off at the fused spur or mains power supply.
- Wait for 60 seconds to allow the internal memory to reset.
- Switch the power back on and, if necessary, press the reset button once briefly.
P1 Your boiler is currently unable to start because a small protective fuse inside the control unit has failed, preventing the system from powering up.
Your boiler is currently unable to start because a small protective fuse inside the control unit has failed, preventing the system from powering up.
Parts commonly replaced
- 1.6A T fuse
- Control board
Related codes
Your boiler is simply performing a routine internal check during its startup process and will be ready to provide heat and hot water as soon as this sequence finishes.
P2 Your boiler is currently unable to start up because a small internal safety fuse has blown, preventing the electrical system from powering on.
Your boiler is currently unable to start up because a small internal safety fuse has blown, preventing the electrical system from powering on.
Parts commonly replaced
- Control board fuse
- Main control unit
Related codes
P3 Your boiler is currently unable to start its control systems because a small internal protective fuse has failed and needs to be swapped for a new one.
Your boiler is currently unable to start its control systems because a small internal protective fuse has failed and needs to be swapped for a new one.
Parts commonly replaced
- Internal 24V fuse
- Main printed circuit board (PCB)