Worcester Bosch Ri 25 HE Fault codes & diagnostics

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

Regular Natural Gas 25 kW 2006-2012 Discontinued

Replaced by: Greenstar i Regular

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Severity at a glance

Each cell = one fault code. Hover to identify.
2 Emergency 22 High 4 Medium 7 Low

All 35 documented codes

Tap any card for details

2.5

Your boiler has detected that the water inside the unit is getting too hot and has automatically shut down to prevent damage.

High Engineer only £120-250

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.

Medium Engineer only £150-250

Parts commonly replaced

  • NTC sensor
  • Printed Circuit Board
  • Main heat exchanger
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.

High Engineer only £200-450

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.

Medium Engineer only £120-250

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.

High Engineer only £250-450

Parts commonly replaced

  • Gas Fire Automator (GFA)
  • Main PCB
Showing 11–20 of 35
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.

High DIY-safe £120-250

What to check first

  1. Check your boiler's pressure gauge and ensure it reads between 1 and 1.5 bar
  2. If the pressure is below 1 bar, use the external filling loop to top up the system
  3. 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.

Medium Engineer only £120-220

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.

High Engineer only £120-220

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.

High Engineer only £150-300

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.

High Engineer only £150-350

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.

High Engineer only £150-300

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.

High Engineer only £120-200

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.

High Engineer only £180-350

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.

High Engineer only £150-350

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.

High Engineer only £150-300

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)

Related codes

Showing 21–30 of 35
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.

High Engineer only £150-250

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.

Medium Engineer only £120-250

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.

High Engineer only £250-450

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.

High Engineer only £120-220

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.

High Engineer only £150-350

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.

High Engineer only £150-300

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.

High Engineer only £250-450

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.

Emergency Engineer only £150-300

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.

Emergency Engineer only £180-350

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.

High Engineer only £180-350

Parts commonly replaced

  • Main PCB
  • Display interface cable
  • User control unit

Related codes

Showing 31–35 of 35
Fd

Your boiler has entered a temporary safety mode because the reset button was held down for too long, essentially causing a software lock.

Low DIY-safe

What to check first

  1. Switch the boiler off at the fused spur or mains power supply.
  2. Wait for 60 seconds to allow the internal memory to reset.
  3. 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.

High Engineer only £120-220

Parts commonly replaced

  • 1.6A T fuse
  • Control board

Related codes

P2

Your boiler is currently unable to start up because a small internal safety fuse has blown, preventing the electrical system from powering on.

High Engineer only £120-220

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.

High Engineer only £100-180

Parts commonly replaced

  • Internal 24V fuse
  • Main printed circuit board (PCB)

Related codes