BoilerFaultCodes 1 green flash
Your boiler has reached the correct temperature and is simply taking a normal break until more heat is needed.
Baxi Suprima 100 Fault codes & diagnostics
129 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Regular Natural Gas 29.3 kW 1998-2010 Discontinued
Replaced by: Baxi 600 Heat
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 1 Emergency
117 High
4 Medium
7 Low
Just want the most common Baxi Suprima 100 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 129 documented codes
Tap any card for details
LED / flash-pattern codes
1 red flash Your boiler has sensed that it is getting too hot or that water isn't moving through the system properly, causing it to shut down for safety.
Your boiler has sensed that it is getting too hot or that water isn't moving through the system properly, causing it to shut down for safety.
What to check first
- Check that all radiator valves are fully open
- Ensure your system water pressure is between 1 and 1.5 bar
- Press the reset button firmly for 5 seconds
Parts commonly replaced
- Temperature thermistor (NTC sensor)
- Circulating pump
- Overheat thermostat
Related codes
2 red flashes Your boiler has become too hot and has automatically shut down for safety.
Your boiler has become too hot and has automatically shut down for safety.
What to check first
- Wait for the boiler to cool down for at least 20 minutes
- Press the 'Reset' button on the control panel
- Check that your radiator valves are open and that your pump is running
Parts commonly replaced
- Overheat Thermostat
- Circulation Pump
- PCB (Printed Circuit Board)
Related codes
3 green flashes Your boiler is temporarily losing its flame and is currently trying to fix the problem by restarting itself.
Your boiler is temporarily losing its flame and is currently trying to fix the problem by restarting itself.
Parts commonly replaced
- Flame rectification probe
- Ignition lead
- PCB (Control board)
- Gas valve
Related codes
3 red flashes Your boiler is failing to light the burner after several attempts, which means your heating and hot water will not work.
Your boiler is failing to light the burner after several attempts, which means your heating and hot water will not work.
What to check first
- Check that your gas emergency control valve is in the 'on' position
- If you have a pre-payment meter, ensure you have credit and the meter is active
- Press the reset button once to see if the boiler initiates a successful ignition cycle
Parts commonly replaced
- Ignition Electrode
- Gas Valve
- PCB (Printed Circuit Board)
Related codes
4 green flashes Your boiler's internal computer parts are temporarily struggling to talk to each other, but the system should usually fix itself automatically.
Your boiler's internal computer parts are temporarily struggling to talk to each other, but the system should usually fix itself automatically.
What to check first
- Wait up to 15 minutes for the boiler to self-reset
- Press the reset button briefly if the light continues to flash
- Turn the boiler power off and back on at the fused spur switch
Parts commonly replaced
- Printed Circuit Board (PCB)
- Wiring harness
4 red flashes Your boiler has stopped working because the internal component responsible for clearing waste gases safely out of the flue is not spinning correctly or has failed.
Your boiler has stopped working because the internal component responsible for clearing waste gases safely out of the flue is not spinning correctly or has failed.
Parts commonly replaced
- Fan assembly
- Air pressure switch
- Printed Circuit Board (PCB)
Related codes
5 green flashes Your boiler has experienced a temporary computer glitch that it is currently trying to fix itself.
Your boiler has experienced a temporary computer glitch that it is currently trying to fix itself.
What to check first
- Wait for the boiler to automatically reset itself
- If the flashing continues for more than 10 minutes, turn the control knob to 'Reset' and then back to the desired temperature
- Monitor the boiler to see if the green light returns to a steady state
Parts commonly replaced
- No parts usually required
- Printed Circuit Board (PCB) if fault persists
5 red flashes Your boiler's internal memory chip has developed a communication fault, meaning it can no longer remember how to operate correctly.
Your boiler's internal memory chip has developed a communication fault, meaning it can no longer remember how to operate correctly.
Parts commonly replaced
- Parameter storage unit (PSU)
- Printed Circuit Board (PCB)
Related codes
6 green flashes Your boiler has experienced a brief internal glitch and is currently trying to restart itself automatically.
Your boiler has experienced a brief internal glitch and is currently trying to restart itself automatically.
What to check first
- Wait for the boiler to complete its self-reset process
- If the flashing continues for more than 15 minutes, press the 'Reset' button once
- Ensure your electricity supply is stable and not fluctuating
Parts commonly replaced
- Control PCB
- Ignition Electrode
Related codes
Showing 11–20 of 129
6 red flashes Your boiler has encountered an internal technical error and has safely shut itself down to prevent damage.
Your boiler has encountered an internal technical error and has safely shut itself down to prevent damage.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Ignition Lead
- Main Cable Harness
FLASH FLASH ON Your boiler has stopped working because the internal fan used to clear out waste gases is not spinning correctly.
Your boiler has stopped working because the internal fan used to clear out waste gases is not spinning correctly.
Parts commonly replaced
- Fan Assembly
- Air Pressure Switch
- PCB
Related codes
FLASH OFF FLASH Your boiler has detected that the electrical supply coming into the unit is too low for it to operate safely.
Your boiler has detected that the electrical supply coming into the unit is too low for it to operate safely.
Parts commonly replaced
- Printed Circuit Board (PCB)
- External Voltage Regulator
FLASH OFF ON Your boiler has become too hot and has automatically shut down to protect itself.
Your boiler has become too hot and has automatically shut down to protect itself.
What to check first
- Locate the reset button on the front control panel.
- Press and hold the reset button for at least 5 seconds.
- Ensure your radiator valves are open and your system pressure is adequate if a gauge is visible.
Parts commonly replaced
- Circulating Pump
- Overheat Thermostat
- Main PCB
- Thermistor
FLASH ON FLASH Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Parts commonly replaced
- Printed Circuit Board (PCB)
- PCB Ignition Lead
FLASH ON ON Your boiler's internal computer has failed and can no longer control the heating process safely.
Your boiler's internal computer has failed and can no longer control the heating process safely.
Parts commonly replaced
- Printed Circuit Board (PCB)
- PCB Ignition Lead
Related codes
ON FLASH FLASH Your boiler has detected that water isn't moving through the system properly or there isn't enough water inside, causing it to overheat quickly.
Your boiler has detected that water isn't moving through the system properly or there isn't enough water inside, causing it to overheat quickly.
What to check first
- Check if your system pressure gauge is too low and top it up if needed
- Ensure all radiator valves and boiler isolation valves are fully open
- Gently bleed your radiators to remove any trapped air pockets
Parts commonly replaced
- Circulating Pump
- Overheat Thermostat
- Printed Circuit Board (PCB)
Related codes
ON FLASH ON Your boiler has stopped working because its internal temperature sensor is reporting an error and needs attention.
Your boiler has stopped working because its internal temperature sensor is reporting an error and needs attention.
Parts commonly replaced
- Thermistor (NTC Sensor)
- Wiring harness
Related codes
ON OFF FLASH Your boiler has detected an electrical wiring error where the power supply cables are connected to the wrong terminals.
Your boiler has detected an electrical wiring error where the power supply cables are connected to the wrong terminals.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Internal Wiring Harness
ON ON FLASH Your boiler's internal computer brain has developed a critical fault and is unable to control the heating process safely.
Your boiler's internal computer brain has developed a critical fault and is unable to control the heating process safely.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring Harness
Related codes
Digital codes
110 Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
What to check first
- Check that all radiator valves are fully open
- Bleed your radiators to remove trapped air using a radiator key
- Wait for the boiler to cool down and press the reset button
Parts commonly replaced
- Overheat Thermostat
- Circulating Pump
- NTC Temperature Sensor
Related codes
117 Your boiler has too much water inside it, which is putting excess pressure on the system and has caused it to shut down for safety.
Your boiler has too much water inside it, which is putting excess pressure on the system and has caused it to shut down for safety.
What to check first
- Check that the silver filling loop valves under the boiler are fully closed
- Bleed water from a radiator via the bleed valve into a basin to reduce pressure
- Monitor the pressure gauge until it returns to between 1.0 and 1.5 bar
- Press the reset button once the pressure is at the correct level
Parts commonly replaced
- Filling loop valve
- Expansion vessel
- Pressure relief valve
Related codes
118 Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
What to check first
- Locate the filling loop (usually a silver flexible hose) underneath or near the boiler
- Slowly open the small valves at either end of the hose until you hear water flowing
- Close the valves tightly once the pressure gauge reaches 1.5 bar
Parts commonly replaced
- Filling loop
- Expansion vessel
- Pressure relief valve
Related codes
119 Your boiler has stopped working because the water pressure in the system has dropped too low to operate safely.
Your boiler has stopped working because the water pressure in the system has dropped too low to operate safely.
What to check first
- Locate the filling loop (usually a silver flexible hose) under or near the boiler.
- Slowly open both valves on the filling loop until you hear water entering the system.
- Close both valves when the pressure gauge reaches between 1 and 1.5 bar.
Parts commonly replaced
- Filling loop
- Pressure sensor
- Expansion vessel
Related codes
125 Your boiler has likely overheated because water isn't moving through the system properly, causing the unit to shut down for safety.
Your boiler has likely overheated because water isn't moving through the system properly, causing the unit to shut down for safety.
What to check first
- Check that your radiator valves and isolation valves are fully open
- Bleed your radiators to remove trapped air from the system
- Gently press the reset button on the front of the boiler panel
Parts commonly replaced
- Central heating pump
- Overheat thermostat
- Flow temperature sensor
Related codes
127 Your boiler has failed to heat the water storage tank to a high enough temperature to kill off potentially harmful bacteria.
Your boiler has failed to heat the water storage tank to a high enough temperature to kill off potentially harmful bacteria.
What to check first
- Check that your hot water cylinder thermostat is not set too low (it should be around 60°C).
- Ensure your hot water heating timings are long enough to allow the tank to reach full temperature.
- Reset the boiler by pressing the reset button to see if the cycle completes on the next attempt.
Parts commonly replaced
- Cylinder thermostat
- Water temperature sensor (NTC thermistor)
- PCB (Control board)
Related codes
128 Your boiler was working but suddenly lost its flame, causing it to stop providing heating or hot water for safety.
Your boiler was working but suddenly lost its flame, causing it to stop providing heating or hot water for safety.
Parts commonly replaced
- Flame Sensing Electrode
- Gas Valve
- PCB (Printed Circuit Board)
Related codes
133 Your boiler has tried to light several times but has been unable to create a steady flame, causing it to shut down for safety.
Your boiler has tried to light several times but has been unable to create a steady flame, causing it to shut down for safety.
What to check first
- Check if your gas supply is active (e.g., check if a gas hob lights or if there is credit on your meter)
- Press and hold the reset button for at least 5 seconds
- Check that the condensate pipe (outside white plastic pipe) isn't frozen if the weather is very cold
Parts commonly replaced
- Ignition Electrode
- Flame Sensing Lead
- Gas Valve
- Printed Circuit Board (PCB)
Related codes
153 Your boiler's internal electronic control board has detected a memory error or has been reset too many times, meaning it can no longer safely manage the heating process without a professional inspection.
Your boiler's internal electronic control board has detected a memory error or has been reset too many times, meaning it can no longer safely manage the heating process without a professional inspection.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Internal Reset Button Mechanism
160 Your boiler has stopped working because the internal fan, which safely exhausts gases, is not spinning at the correct speed or has failed completely.
Your boiler has stopped working because the internal fan, which safely exhausts gases, is not spinning at the correct speed or has failed completely.
Parts commonly replaced
- Fan Assembly
- PCB (Printed Circuit Board)
- Air Pressure Switch
Related codes
Showing 31–40 of 129
162 Your boiler has stopped working because it cannot confirm that the fan is safely moving air and waste gases through the system.
Your boiler has stopped working because it cannot confirm that the fan is safely moving air and waste gases through the system.
Parts commonly replaced
- Air Pressure Switch
- Fan Assembly
- Venting Tubes
Related codes
164 Your boiler has stopped working because it cannot detect the correct flow of water required to operate safely.
Your boiler has stopped working because it cannot detect the correct flow of water required to operate safely.
Parts commonly replaced
- Flow sensor
- Circulation pump
- Pressure switch
Related codes
166 Your boiler has stopped working because it cannot confirm that the fan is safely moving air and exhaust gases through the system.
Your boiler has stopped working because it cannot confirm that the fan is safely moving air and exhaust gases through the system.
Parts commonly replaced
- Air Pressure Switch
- Fan Assembly
- Venture Tube
Related codes
270 Your boiler has detected that it is firing without enough water inside it, causing it to overheat rapidly to prevent damage.
Your boiler has detected that it is firing without enough water inside it, causing it to overheat rapidly to prevent damage.
What to check first
- Check the pressure gauge on your heating system (it should be between 1.0 and 1.5 bar).
- If the pressure is low, use the filling loop valves to top the water up.
- Ensure all radiator valves and isolation valves under the boiler are fully open.
- Press the reset button once the pressure is corrected.
Parts commonly replaced
- Circulation pump
- Overheat thermostat
- Automatic air vent
Related codes
432 Your boiler has detected an electrical grounding issue which is preventing it from starting up safely.
Your boiler has detected an electrical grounding issue which is preventing it from starting up safely.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring harness
- Earth bonding connections
Related codes
433 Your boiler has shut down because it has become dangerously hot and is sensing that water is not moving through the system properly.
Your boiler has shut down because it has become dangerously hot and is sensing that water is not moving through the system properly.
What to check first
- Check that your pump is running and hasn't seized
- Ensure all radiator valves are open to allow water flow
- Bleed all radiators to remove trapped air locks
- Check that the system pressure is within the normal range
Parts commonly replaced
- Circulating Pump
- Overheat Thermostat
- Thermistor (NTC Sensor)
Related codes
E.00 – .04 Your boiler has stopped working because it cannot correctly read the temperature of the water returning to the unit.
Your boiler has stopped working because it cannot correctly read the temperature of the water returning to the unit.
Parts commonly replaced
- Return Temperature Sensor (NTC thermistor)
- Wiring harness
- Control PCB
E.00 – .05 Your boiler has detected a problem with the internal sensor that monitors the temperature of the water returning to the unit, causing it to shut down for safety.
Your boiler has detected a problem with the internal sensor that monitors the temperature of the water returning to the unit, causing it to shut down for safety.
Parts commonly replaced
- Return temperature sensor (NTC thermistor)
- Sensor wiring harness
- Main PCB
E.01 – .02 Your boiler is confused because it thinks the water returning from your radiators is hotter than the water it just sent out, which usually means there is a flow problem or a faulty sensor.
Your boiler is confused because it thinks the water returning from your radiators is hotter than the water it just sent out, which usually means there is a flow problem or a faulty sensor.
Parts commonly replaced
- Flow/Return NTC Thermistors
- Central Heating Pump
- PCB
E.01 – .04 Your boiler is repeatedly losing its flame, which means it cannot stay lit long enough to provide steady heating and hot water.
Your boiler is repeatedly losing its flame, which means it cannot stay lit long enough to provide steady heating and hot water.
Parts commonly replaced
- Ionisation Probe
- Gas Valve
- Ignition Lead
- PCB
Showing 41–50 of 129
E.01 – .11 Your boiler's fan isn't spinning at the correct speed to safely move air through the system, often caused by a mechanical failure or a strong gust of wind blocking the flue.
Your boiler's fan isn't spinning at the correct speed to safely move air through the system, often caused by a mechanical failure or a strong gust of wind blocking the flue.
Parts commonly replaced
- Fan assembly
- Printed Circuit Board (PCB)
- Air pressure switch
E.01 – .12 Your boiler has stopped running because it thinks the water returning to the unit is hotter than the water leaving it, which usually indicates a circulation problem.
Your boiler has stopped running because it thinks the water returning to the unit is hotter than the water leaving it, which usually indicates a circulation problem.
What to check first
- Press the reset button on the front of the boiler once
- Ensure all radiator valves are fully open
- Check that your central heating pump is running and not stuck
Parts commonly replaced
- Temperature Sensor (NTC Thermistor)
- Central Heating Pump
- PCB (Control Board)
E.01 – .17 Your boiler has likely stopped heating because water isn't moving through the system properly or a sensor has lost its connection.
Your boiler has likely stopped heating because water isn't moving through the system properly or a sensor has lost its connection.
What to check first
- Press the 'Reset' button on the boiler control panel for 5 seconds
- Check that all radiator valves and isolation valves under the boiler are fully open
- Ensure your system pressure is topped up to roughly 1.5 bar
Parts commonly replaced
- Circulation pump
- Thermistor (NTC sensor)
- Wiring harness
E.01 – .20 Your boiler has shut down because a sensor detected the internal gases are getting too hot, usually because water isn't moving through the system properly.
Your boiler has shut down because a sensor detected the internal gases are getting too hot, usually because water isn't moving through the system properly.
What to check first
- Check that all radiator valves are fully open
- Ensure the boiler pressure is between 1 and 1.5 bar on the gauge
- Reset the boiler by turning the control knob to 'R' or pressing the reset button
Parts commonly replaced
- Circulation Pump
- Flue Gas Sensor
- Main Heat Exchanger (Cleaning or Replacement)
E.02 – .00 Your boiler is simply confirming that the reset button has been pressed and is now attempting to restart its normal operation.
Your boiler is simply confirming that the reset button has been pressed and is now attempting to restart its normal operation.
What to check first
- Wait up to 30 seconds for the boiler to complete its internal check.
- Monitor the display to see if the message clears and the boiler starts firing.
- If the code persists or changes to a fault, check that your gas supply is turned on.
E.02 – .07 Your boiler has detected that there is not enough water in the heating system to operate safely, causing it to shut down to prevent damage.
Your boiler has detected that there is not enough water in the heating system to operate safely, causing it to shut down to prevent damage.
What to check first
- Locate the external filling loop beneath or near the boiler.
- Slowly open the valves to let water into the system while watching the pressure gauge.
- Close the valves once the pressure reaches between 1.0 and 1.5 bar, then reset the boiler.
Parts commonly replaced
- Filling loop hose
- Pressure sensor/switch
- Expansion vessel
E.02 – .16 Your boiler's internal computer brain has developed a critical error or is no longer communicating properly with its internal systems.
Your boiler's internal computer brain has developed a critical error or is no longer communicating properly with its internal systems.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring harness
E.02 – .17 Your boiler has lost the internal connection between its main control board and the gas system, meaning it cannot safely fire up to provide heat.
Your boiler has lost the internal connection between its main control board and the gas system, meaning it cannot safely fire up to provide heat.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Gas Valve
- Wiring Loom
E.02 – .19 Your boiler’s internal control board has detected an incorrect configuration setting, essentially getting confused about its own identity.
Your boiler’s internal control board has detected an incorrect configuration setting, essentially getting confused about its own identity.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Jumper Link
E.02 – .20 Your boiler's main control board has detected a configuration setting error, likely caused by a hardware connection issue inside the unit.
Your boiler's main control board has detected a configuration setting error, likely caused by a hardware connection issue inside the unit.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Jumper Link
Showing 51–60 of 129
E.02 – .21 Your boiler's electronic control board configuration has been disturbed or was set up incorrectly during a repair.
Your boiler's electronic control board configuration has been disturbed or was set up incorrectly during a repair.
Parts commonly replaced
- PCB (Printed Circuit Board)
- Control Board Interface
E.02 – .47 Your boiler is having trouble communicating with external controls like your thermostat or programmer due to a potential wiring issue.
Your boiler is having trouble communicating with external controls like your thermostat or programmer due to a potential wiring issue.
Parts commonly replaced
- External programmer
- Thermostat wiring
- PCB connectors
E.02 – .48 Your boiler is having trouble communicating with your thermostat or external programmer, meaning it cannot receive the signal to turn on.
Your boiler is having trouble communicating with your thermostat or external programmer, meaning it cannot receive the signal to turn on.
What to check first
- Check that your wireless thermostat has fresh batteries installed
- Ensure the external receiver (the box near the boiler) has power and no tripped switches
- Try re-pairing the thermostat to the receiver following the manufacturer's manual
Parts commonly replaced
- Remote Thermostat
- Wireless Receiver
- PCB (if communication port is faulty)
E.04 – .00 Your boiler's electronic control board has lost communication with the gas valve, meaning it cannot safely ignite to provide heat or hot water.
Your boiler's electronic control board has lost communication with the gas valve, meaning it cannot safely ignite to provide heat or hot water.
Parts commonly replaced
- Gas Valve
- Printed Circuit Board (PCB)
- Wiring Harness
E.04 – .01 Your boiler has stopped working because it cannot correctly measure the temperature of the water flowing through the system due to a faulty sensor or a loose connection.
Your boiler has stopped working because it cannot correctly measure the temperature of the water flowing through the system due to a faulty sensor or a loose connection.
Parts commonly replaced
- NTC Flow Temperature Sensor
- Wiring Harness
E.04 – .02 Your boiler has stopped working because it cannot accurately tell how hot the water is due to a faulty or disconnected sensor.
Your boiler has stopped working because it cannot accurately tell how hot the water is due to a faulty or disconnected sensor.
Parts commonly replaced
- Flow Temperature Sensor (NTC Thermistor)
- Wiring Harness
- Main PCB
E.04 – .03 Your boiler has overheated because water isn't moving through the system properly, causing it to shut down for safety.
Your boiler has overheated because water isn't moving through the system properly, causing it to shut down for safety.
What to check first
- Check that all radiator valves are fully open
- Ensure the central heating bypass valve is open
- Check if the pump is making a humming sound or feels stuck
- Reset the boiler using the reset button once the system has cooled down
Parts commonly replaced
- Circulating Pump
- Overheat Thermostat
- Flow Temperature Sensor
E.04 – .04 Your boiler has detected an issue with the sensor that monitors exhaust gases, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors exhaust gases, causing it to shut down for safety.
Parts commonly replaced
- Flue temperature sensor (NTC)
- Wiring harness
- Printed Circuit Board (PCB)
E.04 – .05 Your boiler has detected a problem with the sensor that monitors exhaust gases, causing it to shut down for safety.
Your boiler has detected a problem with the sensor that monitors exhaust gases, causing it to shut down for safety.
Parts commonly replaced
- Flue Temperature Sensor (NTC)
- Wiring Harness
- PCB
E.04 – .06 Your boiler has switched itself off to prevent overheating because the internal exhaust gases are too hot or water is not moving through the system properly.
Your boiler has switched itself off to prevent overheating because the internal exhaust gases are too hot or water is not moving through the system properly.
Parts commonly replaced
- Circulation pump
- Flue gas temperature sensor (NTC)
- Main heat exchanger (de-scaling)
- Printed Circuit Board (PCB)
Showing 61–70 of 129
E.04 – .08 Your boiler has shut down because it has detected a dangerous level of overheating or a critical failure in the temperature sensors.
Your boiler has shut down because it has detected a dangerous level of overheating or a critical failure in the temperature sensors.
Parts commonly replaced
- Overheat Thermostat
- NTC Temperature Sensor
- Central Heating Pump
- PCB
E.04 – .10 Your boiler is failing to start up because it cannot detect a flame or is struggling to get a steady supply of gas.
Your boiler is failing to start up because it cannot detect a flame or is struggling to get a steady supply of gas.
What to check first
- Check that your gas emergency control valve is in the 'On' position
- If you have a prepayment meter, verify that you have credit available
- Press the Reset button on the front of the boiler for a few seconds
Parts commonly replaced
- Ignition Electrode
- Gas Valve
- Printed Circuit Board (PCB)
E.04 – .12 Your boiler thinks a flame is burning when it shouldn't be, or it is getting too hot, causing it to shut down for safety.
Your boiler thinks a flame is burning when it shouldn't be, or it is getting too hot, causing it to shut down for safety.
Parts commonly replaced
- Ionization Probe
- Gas Valve
- Printed Circuit Board (PCB)
- Burner
E.04 – .13 Your boiler has detected that the fan, which safely removes exhaust fumes, is unable to spin correctly or has a faulty electrical connection.
Your boiler has detected that the fan, which safely removes exhaust fumes, is unable to spin correctly or has a faulty electrical connection.
Parts commonly replaced
- Fan assembly
- Wiring harness
- Printed Circuit Board (PCB)
E.04 – .17 Your boiler has detected a internal failure in the gas control system and has shut down as a safety precaution.
Your boiler has detected a internal failure in the gas control system and has shut down as a safety precaution.
Parts commonly replaced
- Gas Valve
- Printed Circuit Board (PCB)
- Wiring Harness
E0 Your boiler's internal thermometer has stopped working correctly, meaning the system can no longer tell how hot the water is and has shut down as a safety precaution.
Your boiler's internal thermometer has stopped working correctly, meaning the system can no longer tell how hot the water is and has shut down as a safety precaution.
Parts commonly replaced
- NTC Temperature Sensor
- Wiring Harness
- PCB
Related codes
E1 Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
What to check first
- Turn off the boiler and allow it to cool down for at least 20 minutes.
- Check all radiator valves are open and bleed any trapped air from your radiators using a radiator key.
- Press the reset button on the boiler control panel to see if it restarts.
Parts commonly replaced
- Circulation Pump
- Overheat Thermostat
- Thermistor
Related codes
E2 Your boiler is struggling to push water around the system, often caused by trapped air or a blockage stopping the heat from escaping.
Your boiler is struggling to push water around the system, often caused by trapped air or a blockage stopping the heat from escaping.
What to check first
- Turn off the boiler and wait for the radiators to cool.
- Use a radiator key to bleed air from all radiators, starting with the lowest floor.
- Check that all radiator valves (TRVs) are fully open.
- Reset the boiler using the reset button once the system is vented.
Parts commonly replaced
- Circulating Pump
- Auto Air Vent
- System Filter (cleaning)
Related codes
E3 Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring Harness
Related codes
E4 Your boiler is struggling to light its flame, which could be due to trapped air in the system or an issue with the gas supply.
Your boiler is struggling to light its flame, which could be due to trapped air in the system or an issue with the gas supply.
What to check first
- Turn the boiler off and wait for it to cool down
- Use a radiator key to bleed all radiators and remove trapped air
- Check that your gas pre-pay meter is in credit, if applicable
- Press the Reset button on the boiler control panel
Parts commonly replaced
- Ignition Electrode
- Gas Valve
- PCB (Control Board)
Related codes
Showing 71–80 of 129
E09 Your boiler has lost its electrical connection to the gas control valve, meaning it cannot safely ignite to provide heat or hot water.
Your boiler has lost its electrical connection to the gas control valve, meaning it cannot safely ignite to provide heat or hot water.
Parts commonly replaced
- Gas valve wiring harness
- Gas control valve
- Printed Circuit Board (PCB)
E10 Your boiler has lost communication with the sensor that measures the temperature outside, which helps it run more efficiently.
Your boiler has lost communication with the sensor that measures the temperature outside, which helps it run more efficiently.
Parts commonly replaced
- Outdoor weather compensation sensor
- Sensor wiring/cabling
Related codes
E12 Your boiler has detected that water isn't moving through the system correctly, which is preventing it from firing up for safety.
Your boiler has detected that water isn't moving through the system correctly, which is preventing it from firing up for safety.
What to check first
- Check that all radiator valves are fully open
- Ensure the external central heating pump is running and not stuck
- Inspect the system for air locks and bleed radiators if necessary
Parts commonly replaced
- External Circulation Pump
- Differential Pressure Switch
- Diaphragm
Related codes
E13 Your boiler has detected that a internal safety switch is stuck in the 'on' position, preventing the system from starting its normal cycle.
Your boiler has detected that a internal safety switch is stuck in the 'on' position, preventing the system from starting its normal cycle.
Parts commonly replaced
- Differential Water Pressure Switch
- Circulating Pump
- Pcb
Related codes
E15 Your boiler's internal computer has lost control of the gas supply, causing the system to shut down for safety.
Your boiler's internal computer has lost control of the gas supply, causing the system to shut down for safety.
Parts commonly replaced
- Gas Valve
- Printed Circuit Board (PCB)
- Wiring Harness
E20 Your boiler has lost its ability to accurately measure the temperature of the water used for heating, which is preventing the system from running safely.
Your boiler has lost its ability to accurately measure the temperature of the water used for heating, which is preventing the system from running safely.
Parts commonly replaced
- Central Heating NTC Thermistor
- Wiring Harness
Related codes
E28 Your boiler has detected a problem with how it clears exhaust fumes or a faulty sensor, causing it to shut down for safety.
Your boiler has detected a problem with how it clears exhaust fumes or a faulty sensor, causing it to shut down for safety.
Parts commonly replaced
- Flue NTC Sensor
- Air Pressure Switch
- Condensate Trap
Related codes
E40 Your boiler's internal sensor that monitors the temperature of the water returning from your radiators has developed a fault and can no longer read the temperature correctly.
Your boiler's internal sensor that monitors the temperature of the water returning from your radiators has developed a fault and can no longer read the temperature correctly.
Parts commonly replaced
- Central Heating Return NTC Sensor
- Wiring Harness
- PCB (if sensor signals are not being processed)
Related codes
E50 Your boiler has lost its connection to the sensor that monitors the temperature of your hot water, meaning it cannot heat your water safely.
Your boiler has lost its connection to the sensor that monitors the temperature of your hot water, meaning it cannot heat your water safely.
Parts commonly replaced
- Hot water NTC thermistor
- Wiring harness
- Control PCB
Related codes
E53 Your boiler is not getting enough air to burn gas safely and has shut down to prevent a build-up of harmful fumes.
Your boiler is not getting enough air to burn gas safely and has shut down to prevent a build-up of harmful fumes.
Parts commonly replaced
- Fan
- Air Pressure Switch
- Flue terminal seals
Related codes
Showing 81–90 of 129
E54 Your boiler is struggling to detect when you turn on the hot water tap, meaning you may experience cold showers or inconsistent water temperatures.
Your boiler is struggling to detect when you turn on the hot water tap, meaning you may experience cold showers or inconsistent water temperatures.
Parts commonly replaced
- DHW Flow Sensor
- Wiring Harness
- Turbine Sensor
Related codes
E55 Your boiler's internal computer has lost its timing settings and needs to be professionally reconfigured to ensure the gas burns correctly.
Your boiler's internal computer has lost its timing settings and needs to be professionally reconfigured to ensure the gas burns correctly.
Parts commonly replaced
- PCB (Printed Circuit Board)
- Gas Valve
Related codes
E78 Your boiler is having trouble detecting the system's water pressure, which prevents it from firing up to provide heating or hot water.
Your boiler is having trouble detecting the system's water pressure, which prevents it from firing up to provide heating or hot water.
Parts commonly replaced
- Water Pressure Sensor
- Wiring Harness
- PCB (Printed Circuit Board)
Related codes
E83/E84/E85/E86/E87 Your boiler's internal computer has lost its connection with the control systems, meaning the unit cannot receive instructions to provide heating or hot water.
Your boiler's internal computer has lost its connection with the control systems, meaning the unit cannot receive instructions to provide heating or hot water.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Internal Wiring Harness
- External Control Interface
Related codes
E92 Your boiler has failed to calibrate its internal settings correctly while checking the burner's efficiency.
Your boiler has failed to calibrate its internal settings correctly while checking the burner's efficiency.
Parts commonly replaced
- Gas valve
- Electrode set
- Printed Circuit Board (PCB)
Related codes
E100 Your boiler’s internal computer has lost track of the time or date, which is preventing it from running your heating schedule correctly.
Your boiler’s internal computer has lost track of the time or date, which is preventing it from running your heating schedule correctly.
What to check first
- Locate the control panel on the front of the boiler
- Access the menu settings to find the 'Time and Date' section
- Reset the clock to the current time and see if the error clears
Parts commonly replaced
- Printed Circuit Board (PCB)
Related codes
E109 Your boiler is overheating because the heated water cannot flow properly through the pipes or radiators.
Your boiler is overheating because the heated water cannot flow properly through the pipes or radiators.
What to check first
- Check that all radiator valves are fully open
- Ensure the boiler pressure gauge is between 1.0 and 1.5 bar
- Bleed all radiators to remove trapped air pockets
Parts commonly replaced
- Circulation Pump
- Primary Heat Exchanger
- Flow/Return Thermistors
Related codes
E110 Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
What to check first
- Check that your radiator valves are open
- Ensure there is enough water pressure in the system
- Wait for the boiler to cool down and press the reset button
Parts commonly replaced
- Overheat Thermostat
- Circulation Pump
- Thermistor
Related codes
E117 Your boiler has stopped working because there is too much water pressure in the central heating system.
Your boiler has stopped working because there is too much water pressure in the central heating system.
What to check first
- Turn off the boiler and wait for the radiators to cool down.
- Locate a radiator bleed valve and use a key to release water into a container.
- Monitor the boiler pressure gauge until it drops back into the green zone (typically 1.0 to 1.5 bar).
Parts commonly replaced
- Filling loop valve
- Expansion vessel
- Pressure relief valve
Related codes
E118 Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
What to check first
- Locate the filling loop, which is usually a flexible silver hose under or near the boiler.
- Slowly open the one or two small valves on the hose until you hear water running.
- Watch the pressure gauge and close the valves tightly once the needle reaches between 1 and 1.5 bar.
Parts commonly replaced
- Filling loop valve
- Pressure sensor
- Expansion vessel
Related codes
Showing 91–100 of 129
E119 Your boiler has detected that the water pressure in the system is too low to operate safely.
Your boiler has detected that the water pressure in the system is too low to operate safely.
What to check first
- Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.
- Slowly open the valve(s) to allow water into the system while watching the pressure gauge.
- Close the valves once the needle reaches between 1.0 and 1.5 bar, then reset the boiler.
Parts commonly replaced
- Water Pressure Switch
- Filling Loop Valve
- Expansion Vessel
Related codes
E125 Your boiler is struggling to move hot water around your heating system, causing it to overheat and shut down for safety.
Your boiler is struggling to move hot water around your heating system, causing it to overheat and shut down for safety.
What to check first
- Check that your radiator valves and any external isolation valves are fully open
- Bleed all radiators to remove trapped air that might be blocking water flow
- Gently restart the boiler using the reset button
Parts commonly replaced
- Central heating pump
- Internal pipework (de-sludging)
- Flow/Return thermistors
Related codes
E128 Your boiler is repeatedly losing its flame during operation, which has caused it to lock out for safety reasons.
Your boiler is repeatedly losing its flame during operation, which has caused it to lock out for safety reasons.
What to check first
- Press the reset button for five seconds and release
- Check that your gas meter has credit and the isolation valve is open
- Ensure there are no external obstructions to the flue pipe outside
Parts commonly replaced
- Flame sensing electrode
- Ignition lead
- Gas valve
Related codes
E129 Your boiler is struggling to keep a flame lit while it tries to automatically adjust its settings, causing the system to shut down for safety.
Your boiler is struggling to keep a flame lit while it tries to automatically adjust its settings, causing the system to shut down for safety.
Parts commonly replaced
- Flame sensing electrode
- Ignition lead
- Gas valve
- PCB
Related codes
E130 Your boiler has shut down because a sensor has detected that the exhaust gases are becoming too hot, which could indicate a safety issue or a blockage.
Your boiler has shut down because a sensor has detected that the exhaust gases are becoming too hot, which could indicate a safety issue or a blockage.
Parts commonly replaced
- Flue NTC Sensor
- Main PCB
- Heat Exchanger
Related codes
E131 Your boiler has shut down because it detected that the exhaust gases have become dangerously hot, which points to a potential safety issue or an internal blockage.
Your boiler has shut down because it detected that the exhaust gases have become dangerously hot, which points to a potential safety issue or an internal blockage.
Parts commonly replaced
- Flue Thermistor
- Heat Exchanger
- Main PCB
Related codes
E133 Your boiler has tried to light several times but cannot establish a steady gas supply or sense a flame, causing it to shut down for safety.
Your boiler has tried to light several times but cannot establish a steady gas supply or sense a flame, causing it to shut down for safety.
What to check first
- Check if your gas meter has credit (if on a prepay meter).
- Ensure your external gas emergency control valve is in the 'on' position.
- Attempt to reset the boiler using the reset button or dial once the gas supply is confirmed.
Parts commonly replaced
- Ignition Electrode
- Flame Sensing Probe
- Gas Valve
- PCB (Printed Circuit Board)
Related codes
E134 Your boiler has failed to ignite because gas did not flow when requested, often caused by a temporary interruption in the gas supply or a component fault.
Your boiler has failed to ignite because gas did not flow when requested, often caused by a temporary interruption in the gas supply or a component fault.
Parts commonly replaced
- Gas Valve
- Spark Electrode
- Ignition Lead
- Printed Circuit Board (PCB)
Related codes
E135 Your boiler has stopped working because the gas supply reaching the internal burner has been interrupted or cut off.
Your boiler has stopped working because the gas supply reaching the internal burner has been interrupted or cut off.
Parts commonly replaced
- Gas Valve
- Ignition Lead
- Printed Circuit Board (PCB)
Related codes
E154 Your boiler has detected that the water temperature readings are inconsistent, which usually means the water isn't flowing correctly or a sensor has failed.
Your boiler has detected that the water temperature readings are inconsistent, which usually means the water isn't flowing correctly or a sensor has failed.
Parts commonly replaced
- Flow temperature sensor
- Return temperature sensor
- Circulation pump
Related codes
Showing 101–110 of 129
E160 Your boiler has stopped working because the fan that clears away waste gases is either faulty or not starting correctly.
Your boiler has stopped working because the fan that clears away waste gases is either faulty or not starting correctly.
Parts commonly replaced
- Fan assembly
- Fan wiring harness
- External PCB
Related codes
E160 / E161 Your boiler has detected a problem with the fan that clears out exhaust gases, which is preventing the system from starting up for safety reasons.
Your boiler has detected a problem with the fan that clears out exhaust gases, which is preventing the system from starting up for safety reasons.
Parts commonly replaced
- Fan assembly
- Printed Circuit Board (PCB)
- Wiring harness
Related codes
E163 Your boiler has detected a problem with the temperature sensor that manages your hot water, meaning it cannot accurately tell how hot the water is.
Your boiler has detected a problem with the temperature sensor that manages your hot water, meaning it cannot accurately tell how hot the water is.
Parts commonly replaced
- DHW NTC thermistor sensor
- Wiring harness connection
Related codes
E164 Your boiler has detected an issue with the sensor that monitors water pressure, meaning it cannot confirm if there is enough water to operate safely.
Your boiler has detected an issue with the sensor that monitors water pressure, meaning it cannot confirm if there is enough water to operate safely.
Parts commonly replaced
- Water pressure sensor
- Pressure switch wiring
Related codes
E167 Your boiler's internal computer has developed a fault and can no longer communicate with the rest of the system.
Your boiler's internal computer has developed a fault and can no longer communicate with the rest of the system.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring Harness
Related codes
E168 Your boiler’s internal computer has encountered a memory or signal error and has stopped working to protect itself.
Your boiler’s internal computer has encountered a memory or signal error and has stopped working to protect itself.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Wiring Harness
Related codes
E193 Your boiler has detected that water is not moving through the system quickly enough before the burner ignites, often due to a blockage or a pump issue.
Your boiler has detected that water is not moving through the system quickly enough before the burner ignites, often due to a blockage or a pump issue.
What to check first
- Check that your central heating valves and radiator valves are fully open
- Ensure the system water pressure is topped up to between 1 and 1.5 bar
- Gently bleed your radiators to remove any trapped air pockets
Parts commonly replaced
- Circulation pump
- Flow temperature sensor
- Return temperature sensor
Related codes
E270 Your boiler is overheating because water isn't moving through the system properly, causing it to shut down to prevent damage.
Your boiler is overheating because water isn't moving through the system properly, causing it to shut down to prevent damage.
What to check first
- Check that the boiler pressure is between 1.0 and 1.5 bar
- Ensure all radiator valves and isolation valves are fully open
- Bleed your radiators to remove any trapped air pockets
Parts commonly replaced
- Central heating pump
- Flow/Return thermistors
- Automatic air vent
Related codes
E317 Your boiler has detected an issue with the electrical power timing coming into the unit, which means it cannot safely coordinate its internal operations.
Your boiler has detected an issue with the electrical power timing coming into the unit, which means it cannot safely coordinate its internal operations.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Voltage Stabiliser
E321 Your boiler's hot water sensor is reporting an incorrect temperature or has developed a fault, meaning the system cannot safely heat your water.
Your boiler's hot water sensor is reporting an incorrect temperature or has developed a fault, meaning the system cannot safely heat your water.
Parts commonly replaced
- Hot water NTC thermistor
- Connecting wiring harness
Related codes
Showing 111–120 of 129
E384 Your boiler thinks it is seeing a flame when it shouldn't be, causing the system to shut down for safety.
Your boiler thinks it is seeing a flame when it shouldn't be, causing the system to shut down for safety.
Parts commonly replaced
- Flame sensing electrode
- Printed Circuit Board (PCB)
- Gas valve
Related codes
E385 Your boiler is not receiving enough electrical power to run safely, likely due to a problem with the mains supply or an internal circuit board fault.
Your boiler is not receiving enough electrical power to run safely, likely due to a problem with the mains supply or an internal circuit board fault.
Parts commonly replaced
- Printed Circuit Board (PCB)
- External Power Supply Unit
Related codes
E430 Your boiler has noticed the water pressure is slightly low or fluctuating and is performing a quick check to see if it can still operate safely.
Your boiler has noticed the water pressure is slightly low or fluctuating and is performing a quick check to see if it can still operate safely.
What to check first
- Check the pressure gauge on your boiler or central heating system.
- If the pressure is below 1.0 bar, use the external filling loop to top it up to 1.5 bar.
- Ensure all radiator valves are open and bleed any trapped air from the radiators.
- Reset the boiler to see if the message clears.
Parts commonly replaced
- External filling loop
- Water pressure sensor
- Expansion vessel
Related codes
H.01 – .00 Your boiler has lost its connection to the gas control system, meaning it cannot safely light itself to provide heat or hot water.
Your boiler has lost its connection to the gas control system, meaning it cannot safely light itself to provide heat or hot water.
Parts commonly replaced
- Main PCB (Control Board)
- Gas Valve Wiring Harness
- Gas Valve
H.01 – .05 Your boiler is overheating because water isn't moving through the system quickly enough or the temperature sensors are giving conflicting readings.
Your boiler is overheating because water isn't moving through the system quickly enough or the temperature sensors are giving conflicting readings.
What to check first
- Check that all radiator valves are fully open
- Ensure the system pressure is between 1 and 1.5 bar
- Bleed all radiators to remove trapped air
- Check that the external pump (if visible) is running
Parts commonly replaced
- Circulation pump
- Flow/Return thermistors (NTC sensors)
- Heat exchanger (flushing/cleaning)
H.01 – .08 Your boiler is overheating because water isn't moving through the system quickly enough or a sensor has detected a sudden, unsafe rise in temperature.
Your boiler is overheating because water isn't moving through the system quickly enough or a sensor has detected a sudden, unsafe rise in temperature.
What to check first
- Check that all radiator valves are fully open to allow water flow
- Ensure the central heating pump is running and hasn't seized
- Attempt to reset the boiler once the system has cooled down
Parts commonly replaced
- Temperature Sensor (NTC Thermistor)
- Central Heating Pump
- Flow Switch
H.01 – .14 Your boiler has got too hot or water isn't moving through the system quickly enough, causing it to shut down for safety.
Your boiler has got too hot or water isn't moving through the system quickly enough, causing it to shut down for safety.
What to check first
- Check that your radiator valves are open and not turned to zero.
- Ensure your external heating pump is running if accessible.
- Reset the boiler using the reset button once the system has cooled down.
Parts commonly replaced
- Central heating pump
- Flow temperature sensor (NTC thermistor)
- Main PCB
H.01 – .18 Your boiler is struggling to move water through the system, which is causing it to overheat and shut down for safety.
Your boiler is struggling to move water through the system, which is causing it to overheat and shut down for safety.
What to check first
- Check that your boiler pressure is between 1 and 1.5 bar on the gauge
- Ensure all radiator valves and the main isolation valves under the boiler are fully open
- Gently bleed your radiators to remove any trapped air pockets
Parts commonly replaced
- Circulating Pump
- Flow/Return Thermistor
- Overheat Thermostat
Related codes
H.01 – .21 Your boiler is overheating because water isn't moving through the system quickly enough when you turn on your hot taps.
Your boiler is overheating because water isn't moving through the system quickly enough when you turn on your hot taps.
Parts commonly replaced
- Circulation pump
- DHW temperature sensor (NTC thermistor)
- Plate heat exchanger
H.02 – .02 Your boiler's internal computer has lost its settings and doesn't know how to run the system correctly.
Your boiler's internal computer has lost its settings and doesn't know how to run the system correctly.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Configuration Plug
Showing 121–129 of 129
H.02 – .03 Your boiler's internal computer brain is temporarily confused because its setup settings do not match the specific model requirements.
Your boiler's internal computer brain is temporarily confused because its setup settings do not match the specific model requirements.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Configuration Key
H.02 – .04 Your boiler's computer system is confused and having trouble reading the internal settings it needs to operate properly.
Your boiler's computer system is confused and having trouble reading the internal settings it needs to operate properly.
What to check first
- Locate the reset button on the front control panel.
- Press and hold the reset button for at least 5 seconds.
- Wait for the boiler to restart; if the code persists, a professional must recalibrate the software.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Parameter Chip
H.02 – .06 Your boiler has detected that the water pressure is too low, likely caused by a leak somewhere in the system or air being trapped in the pipes.
Your boiler has detected that the water pressure is too low, likely caused by a leak somewhere in the system or air being trapped in the pipes.
What to check first
- Check the pressure gauge on your system; if it is below 1 bar, it needs topping up.
- Locate the internal or external filling loop and slowly turn the valves to increase the pressure to 1.5 bar.
- Check all visible radiator valves and pipework for damp patches or active leaks.
Parts commonly replaced
- Filling loop
- Expansion vessel
- Pressure relief valve
- Automatic air vent
H.03 -.00 Your boiler has stopped working because its internal sensors are unable to communicate correctly with the main control board.
Your boiler has stopped working because its internal sensors are unable to communicate correctly with the main control board.
Parts commonly replaced
- NTC Temperature Sensor
- Flue Sensor
- Wiring Harness
Related codes
H.03 – .01 Your boiler's internal computer has lost communication with the main control system, meaning it cannot process instructions to heat your home.
Your boiler's internal computer has lost communication with the main control system, meaning it cannot process instructions to heat your home.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Wiring Harness
- Display Interface
Related codes
H.03 – .02 Your boiler has unexpectedly lost its flame while it was running, which means it cannot heat your water or radiators.
Your boiler has unexpectedly lost its flame while it was running, which means it cannot heat your water or radiators.
What to check first
- Check if other gas appliances, like a cooker, are working to confirm gas supply
- Ensure your pre-payment gas meter has sufficient credit
- Press the reset button once to see if the boiler restarts
Parts commonly replaced
- Flame sensing electrode
- Gas valve
- Ignition lead
OFF OFF OFF Your boiler has no electricity and is not receiving any power, meaning it cannot operate at all.
Your boiler has no electricity and is not receiving any power, meaning it cannot operate at all.
What to check first
- Check if your main consumer unit (fuse box) has a tripped circuit breaker.
- Ensure the boiler's fused spur switch (usually located near the boiler) is turned on.
- Check and replace the 3-amp fuse inside the boiler's power switch if it has blown.
Parts commonly replaced
- PCB (Printed Circuit Board)
- Wiring harness
- External fuse
ON OFF ON Your boiler has failed to light after several attempts and has locked itself out for safety.
Your boiler has failed to light after several attempts and has locked itself out for safety.
What to check first
- Press the 'Reset' button on the front of the boiler control panel for 5 seconds.
- Check that your gas supply is active (e.g., check if other gas appliances like a hob are working).
- Ensure your credit is topped up if you have a pre-payment gas meter.
Parts commonly replaced
- Ignition Electrode
- Printed Circuit Board (PCB)
- Gas Valve
ON ON ON Your boiler has detected an internal electrical communication failure, meaning the control board cannot talk to the parts that fire up the heat.
Your boiler has detected an internal electrical communication failure, meaning the control board cannot talk to the parts that fire up the heat.
Parts commonly replaced
- Wiring harness
- PCB (Printed Circuit Board)
- Control board connection kit