Baxi Eco Elite Fault codes & diagnostics

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

Combi Natural Gas 24-28 kW 2013-2016 Discontinued

Replaced by: Main Eco Compact

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 111 High 8 Medium 9 Low
Just want the most common Baxi Eco Elite 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 green flash

Your boiler has reached its set temperature and is temporarily pausing its operation as a normal part of its heating cycle.

Low DIY-safe

What to check first

  1. No action is necessary as this is normal behavior
  2. Wait for the water temperature to drop, and the boiler will restart automatically
  3. Check that your room thermostat is set to the desired temperature
Full explanation for 1 green flash
1 red flash

Your boiler has likely overheated or a sensor has detected an issue with how water is flowing through the system.

High DIY-safe £90-220

What to check first

  1. Check that your radiator valves are open
  2. Ensure there are no blockages in the system
  3. Turn the selector switch to the reset position for five seconds and then back to the desired mode

Parts commonly replaced

  • Temperature Sensor (NTC)
  • Water Pressure Switch
  • Circulation Pump

Related codes

Full explanation for 1 red flash
2 red flashes

Your boiler has become too hot and has shut itself down for safety reasons.

High DIY-safe £100-350

What to check first

  1. Ensure all radiator valves (TRVs) are open to allow water to circulate
  2. Check that your system pressure is between 1.0 and 1.5 bar on the gauge
  3. Wait for the boiler to cool down and then turn the selector switch to 'R' for five seconds to reset

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Heat Exchanger

Related codes

Full explanation for 2 red flashes
3 green flashes

Your boiler is struggling to keep its flame lit and is currently trying to fix itself automatically before shutting down.

Medium Engineer only £90-280

Parts commonly replaced

  • Ignition electrode
  • Flame sensing probe
  • Gas valve
  • Condensate trap

Related codes

Full explanation for 3 green flashes
3 red flashes

Your boiler has failed to light several times and has now locked itself out for safety.

High DIY-safe £100-£250

What to check first

  1. Check that your gas supply is turned on at the meter
  2. Check if other gas appliances in your home are working
  3. Press and hold the selector switch in the 'reset' position for 5 seconds

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Spark Generator

Related codes

Full explanation for 3 red flashes
4 green flashes

Your boiler is having a temporary 'handshake' problem between its internal computers and will usually try to fix itself automatically.

Low DIY-safe £0-280

What to check first

  1. Wait for 30 minutes to see if the error clears itself as it is a temporary communication fault
  2. Turn the selector switch to the reset position for five seconds
  3. Switch the main electrical power to the boiler off and back on again

Parts commonly replaced

  • None (usually self-resets)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 4 green flashes
4 red flashes

Your boiler's internal fan, which safely removes waste gases, is not spinning or starting correctly, causing the system to shut down for safety.

High Engineer only £200-£450

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Air pressure switch

Related codes

Full explanation for 4 red flashes
5 green flashes

Your boiler is experiencing a temporary computer glitch while trying to read its internal settings and will attempt to fix itself shortly.

Low DIY-safe £0-280

What to check first

  1. Wait for the boiler to automatically reset itself
  2. If the flashing continues, turn the selector switch to the reset position for 5 seconds
  3. Monitor the boiler to ensure it returns to normal operation

Parts commonly replaced

  • No parts usually required
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 5 green flashes
5 red flashes

Your boiler's internal memory chip has developed a communication fault, meaning the control board can no longer remember its specific operating settings.

High Engineer only £180-350

Parts commonly replaced

  • Parameter Storage Unit (PSU)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 5 red flashes
6 green flashes

Your boiler has encountered a minor, temporary glitch and is currently pausing before trying to restart itself automatically.

Low DIY-safe £0-80

What to check first

  1. Wait for the boiler to complete its self-reset process
  2. If the flashing continues for more than 10 minutes, turn the selector switch to the reset position for five seconds
  3. Check that your credit or prepaid gas meter has sufficient funds

Parts commonly replaced

  • No parts usually required
  • Flame sensing electrode

Related codes

Full explanation for 6 green flashes
Showing 11–20 of 129
6 red flashes

Your boiler has likely experienced a flame failure or ignition problem, meaning it cannot detect the fire required to heat your water.

High DIY-safe £120-280

What to check first

  1. Check that your gas prepay meter has credit
  2. Ensure other gas appliances in your home, like a hob, are working correctly
  3. Turn the selector switch to the reset position for five seconds and then back to 'On'

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve

Related codes

Full explanation for 6 red flashes
FLASH FLASH ON

Your boiler's fan, which safely pushes exhaust fumes outside, has stopped working or is not spinning at the correct speed.

High Engineer only £250-450

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Main PCB

Related codes

Full explanation for FLASH FLASH ON
FLASH OFF FLASH

Your boiler has stopped working because the electricity supply reaching it is too low to run the internal components safely.

High DIY-safe £100-350

What to check first

  1. Check if there is a regional power cut or if other appliances in your home are flickering.
  2. Ensure the boiler's fused spur switch is fully turned on and the plug is pushed in properly.
  3. If you use a prepaid electric meter, check that you have sufficient credit remaining.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Voltage Stabiliser
  • Electrical Wiring

Related codes

Full explanation for FLASH OFF FLASH
FLASH OFF ON

Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.

High DIY-safe £100-280

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate
  2. Ensure your system pressure is topped up to between 1 and 1.5 bar
  3. Turn the selector switch to the reset position for five seconds and then back to heat/hot water

Parts commonly replaced

  • Overheat Thermostat
  • Circulating Pump
  • Main Heat Exchanger
  • Temperature Sensors (NTC)

Related codes

Full explanation for FLASH OFF ON
FLASH ON FLASH

Your boiler's internal computer has developed a fault and can no longer control the heating system correctly.

High Engineer only £280-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for FLASH ON FLASH
FLASH ON ON

Your boiler’s internal control computer has developed a fault and can no longer manage the heating system safely.

High Engineer only £250-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for FLASH ON ON
ON FLASH FLASH

Your boiler has detected that water is not moving through the system correctly or there isn't enough water inside the unit to operate safely.

High DIY-safe £120-350

What to check first

  1. Check the pressure gauge on the front of the boiler; if it is below 1.0 bar, use the filling loop to top it up to 1.5 bar.
  2. Ensure all radiator valves and isolation valves under the boiler are fully open.
  3. Gently bleed your radiators to remove any trapped air that might be blocking water flow.

Parts commonly replaced

  • Circulation pump
  • Water pressure switch
  • Heat exchanger

Related codes

Full explanation for ON FLASH FLASH
ON FLASH ON

Your boiler's internal temperature sensors are giving an incorrect reading, which means the system cannot safely heat your water.

High Engineer only £90-160

Parts commonly replaced

  • NTC Thermistor
  • Temperature Sensor
  • Wiring Harness

Related codes

Full explanation for ON FLASH ON
ON OFF FLASH

Your boiler has detected that the electrical wiring coming from your home’s power supply is connected the wrong way around.

High Engineer only £80-130

Parts commonly replaced

  • External wiring connection
  • Printed Circuit Board (PCB)

Related codes

Full explanation for ON OFF FLASH
ON ON FLASH

Your boiler's internal computer has encountered a critical error and needs a professional electronic inspection.

High Engineer only £280-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for ON ON FLASH
Digital codes
110

Your boiler has switched itself off because it has gotten too hot, likely due to trapped air or a blockage stopping water from circulating properly.

High DIY-safe £100-280

What to check first

  1. Turn off the boiler and allow it to cool down completely.
  2. Use a radiator key to bleed all radiators and remove trapped air.
  3. Check the boiler pressure gauge and top it up to 1.5 bar if it has dropped.
  4. Press the 'Reset' button on the boiler control panel.

Parts commonly replaced

  • Circulation Pump
  • Overheat Thermostat
  • NTC Temperature Sensor

Related codes

Full explanation for 110
117

Your boiler has too much water inside, which is putting too much pressure on the system.

Medium DIY-safe £0-120

What to check first

  1. Check that the filling loop valves are tightly closed
  2. Bleed water from a radiator using a bleed key into a container
  3. Monitor the pressure gauge until it returns to the green zone (approx 1.5 bar)
  4. Reset the boiler to clear the fault code

Parts commonly replaced

  • Filling loop valve
  • Pressure relief valve (PRV)
  • Expansion vessel

Related codes

Full explanation for 117
118

Your boiler has detected that the water pressure is too low for the system to operate safely, which has caused it to shut down temporarily.

High DIY-safe £0-160

What to check first

  1. Locate the filling loop (a flexible silver hose) underneath the boiler.
  2. Slowly open the tap or taps on the filling loop until you hear water entering the system.
  3. Watch the pressure gauge and close the taps firmly once the needle reaches between 1.0 and 1.5 bar.
  4. Restart the boiler if it does not automatically reset.

Parts commonly replaced

  • Filling loop
  • Expansion vessel re-pressurisation
  • Pressure sensor

Related codes

Full explanation for 118
119

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

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (a flexible silver hose) underneath or near the boiler.
  2. Open the one or two small taps on the filling loop until you hear water entering the system.
  3. Watch the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for 119
125

Your boiler has detected that water is failing to move through the system correctly, which could be caused by air locks, a blockage, or a pump issue.

High DIY-safe £180-450

What to check first

  1. Check if your radiator valves are open
  2. Ensure the system pressure is between 1.0 and 1.5 bar
  3. Gently bleed your radiators to remove trapped air

Parts commonly replaced

  • Circulation pump
  • Flow temperature sensor
  • Automatic air vent

Related codes

Full explanation for 125
127

Your boiler has failed to heat the water to a high enough temperature to complete its automatic routine cleaning cycle that prevents bacteria growth.

Low DIY-safe £0-120

What to check first

  1. Check that your hot water temperature dial is set to its normal operating position, not at its lowest.
  2. Ensure the boiler has been left switched on consistently so it can complete its timed weekly heat cycle.
  3. Restart the boiler using the reset button to see if the cycle completes successfully on the next attempt.

Parts commonly replaced

  • No parts usually required
  • Hot water temperature sensor (NTC thermistor)
  • Diverter valve

Related codes

Full explanation for 127
128

Your boiler started to heat up but the flame went out unexpectedly while it was running.

High Engineer only £100-£350

Parts commonly replaced

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

Related codes

Full explanation for 128
133

Your boiler has tried to light several times but cannot create a steady flame, causing it to shut down for safety.

High DIY-safe £100-280

What to check first

  1. Check that your gas pre-payment meter (if applicable) has credit.
  2. Ensure your external gas emergency control valve is in the 'on' position.
  3. Hold the selector switch to 'R' for five seconds to attempt a reset.
  4. If it is freezing outside, check that your white plastic condensate pipe hasn't frozen.

Parts commonly replaced

  • Spark electrode
  • Gas valve
  • Ignition lead
  • PCB

Related codes

Full explanation for 133
153

Your boiler has been manually reset too many times in a short period and has temporarily locked itself for safety.

Medium DIY-safe £0-120

What to check first

  1. Locate the selector switch on the front of the boiler.
  2. Turn the switch to the 'R' (Reset) position and hold it for at least 5 seconds.
  3. Release the switch and wait for the boiler to attempt to restart.

Parts commonly replaced

  • No parts usually required
  • Printed Circuit Board (PCB) if fault persists

Related codes

Full explanation for 153
160

Your boiler has stopped working because the internal fan, which safely pushes exhaust gases out of the flue, is not running at the correct speed.

High Engineer only £220-£450

Parts commonly replaced

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

Related codes

Full explanation for 160
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.

High Engineer only £120-280

Parts commonly replaced

  • Air Pressure Switch
  • Venturi Tube
  • Fan

Related codes

Full explanation for 162
164

Your boiler is struggling to detect the correct water pressure or movement, causing it to stop running for safety.

High DIY-safe £120-240

What to check first

  1. Check the pressure gauge on the front of the boiler
  2. If the pressure is below 1.0 bar, use the filling loop to top it up to 1.5 bar
  3. Reset the boiler by turning the selector knob to 'R' for five seconds

Parts commonly replaced

  • Water pressure sensor
  • Flow switch
  • Wiring harness

Related codes

Full explanation for 164
166

Your boiler has detected an issue with how it clears exhaust gases, preventing it from firing up safely to provide heating and hot water.

High Engineer only £120-220

Parts commonly replaced

  • Air Pressure Switch
  • Venturi Tube
  • Fan

Related codes

Full explanation for 166
270

Your boiler has detected that there is no water circulating through the heat exchanger, which is causing it to overheat rapidly and shut down for safety.

High DIY-safe £120-£350

What to check first

  1. Check if the water pressure gauge is between 1.0 and 1.5 bar
  2. Top up the system pressure using the filling loop if it is too low
  3. Ensure all radiator valves and boiler isolation valves are fully open
  4. Reset the boiler once the pressure is corrected

Parts commonly replaced

  • Circulating Pump
  • Main Heat Exchanger
  • Overheat Thermostat

Related codes

Full explanation for 270
432

Your boiler has stopped working because it has detected a problem with its electrical safety grounding system.

High Engineer only £100-250

Parts commonly replaced

  • Main PCB
  • Wiring Harness
  • Earth electrode

Related codes

Full explanation for 432
433

Your boiler has switched itself off because its internal water temperature has become too hot, likely due to a circulation blockage or a pump failure.

High DIY-safe £150-350

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. Try resetting the boiler to see if the fault clears after cooling down

Parts commonly replaced

  • Circulation pump
  • Heat exchanger (descaling)
  • Flow temperature sensor

Related codes

Full explanation for 433
E.00 – .04

Your boiler has stopped working because it cannot communicate with the internal sensor that monitors the temperature of the water returning to the unit.

High Engineer only £90-160

Parts commonly replaced

  • Return Temperature Sensor (NTC Thermistor)
  • Wiring harness or connector
Full explanation for E.00 – .04
E.00 – .05

Your boiler has stopped working because it cannot correctly measure the temperature of the water returning to the unit due to a faulty sensor or loose wiring.

High Engineer only £90-£160

Parts commonly replaced

  • Return NTC Temperature Sensor
  • Wiring Harness

Related codes

Full explanation for E.00 – .05
E.01 – .02

Your boiler has stopped working because it believes the water returning to the unit is hotter than the water leaving it, which usually indicates a circulation problem or a sensor error.

High DIY-safe £90-180

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the boiler pressure is between 1.0 and 1.5 bar
  3. Perform a reset by turning the selector switch to 'R' for five seconds

Parts commonly replaced

  • Temperature sensors (NTC thermistors)
  • Circulation pump
  • Main PCB

Related codes

Full explanation for E.01 – .02
E.01 – .04

Your boiler is struggling to keep its flame lit and has shut itself down as a safety precaution after several failed attempts to stay running.

High DIY-safe £120-350

What to check first

  1. Check that your gas prepayment meter has credit (if applicable)
  2. Ensure your external gas emergency control valve is in the 'on' position
  3. Press the Reset button for five seconds to see if the boiler restarts

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Ignition lead

Related codes

Full explanation for E.01 – .04
Showing 41–50 of 129
E.01 – .11

Your boiler's fan is not spinning at the correct speed to safely clear away exhaust fumes, possibly due to a blockage or a mechanical failure.

High Engineer only £180-350

Parts commonly replaced

  • Fan motor
  • Air pressure switch
  • Boiler PCB

Related codes

Full explanation for E.01 – .11
E.01 – .12

Your boiler has detected that the water coming back from your radiators is hotter than the water going out, which usually means there is a blockage or a circulation problem.

High DIY-safe £100-280

What to check first

  1. Press and hold the reset button for five seconds
  2. Ensure all radiator valves are fully open
  3. Check that the boiler pressure is between 1.0 and 1.5 bar on the gauge

Parts commonly replaced

  • Return temperature sensor (NTC)
  • Circulation pump
  • Plate heat exchanger
Full explanation for E.01 – .12
E.01 – .17

Your boiler has stopped working because water is not moving through the system properly or a internal sensor has lost its connection.

High DIY-safe £100-250

What to check first

  1. Locate the selector switch on the front of the boiler
  2. Turn the switch to the 'R' (Reset) position and hold for at least 5 seconds
  3. Return the switch to your desired heating or hot water setting

Parts commonly replaced

  • Temperature Sensor (NTC Thermistor)
  • Circulation Pump
  • Wiring Harness

Related codes

Full explanation for E.01 – .17
E.01 – .20

Your boiler has switched itself off because it has become too hot, which is usually caused by water not moving through the system properly or a faulty sensor.

High DIY-safe £100-280

What to check first

  1. Check that your central heating valves and radiator valves are fully open
  2. Ensure the boiler pressure is between 1.0 and 1.5 bar
  3. Try resetting the boiler by turning the selector switch to the reset position for five seconds

Parts commonly replaced

  • Flue Overheat Thermostat
  • Main Heat Exchanger
  • Circulation Pump

Related codes

Full explanation for E.01 – .20
E.02 – .00

Your boiler is letting you know that the reset button has been held or pressed recently.

Low DIY-safe

What to check first

  1. Wait for the boiler to complete its restart cycle
  2. If the code persists, ensure the reset button is not stuck or being held down
  3. Monitor the display to see if a different fault code appears after the reset
Full explanation for E.02 – .00
E.02 – .07

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

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath the boiler.
  2. Slowly open the one or two taps on the hose until you hear water flowing.
  3. Watch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar.

Parts commonly replaced

  • Filling loop valve
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for E.02 – .07
E.02 – .16

Your boiler's computer brain has suffered an internal communication failure or electrical damage, meaning it can no longer control the heating process safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal wiring harness
Full explanation for E.02 – .16
E.02 – .17

Your boiler's internal computer has lost contact with the gas control system, meaning it cannot safely manage the fuel needed to generate heat.

High Engineer only £180-450

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)
  • Communication Wiring Loom
Full explanation for E.02 – .17
E.02 – .19

Your boiler's internal configuration settings have been altered or are mismatched, which is preventing the computer from operating correctly.

High Engineer only £80-160

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Selector Jumpers

Related codes

Full explanation for E.02 – .19
E.02 – .20

Your boiler's internal computer settings have been changed or are configured incorrectly, preventing it from running properly.

High Engineer only £80-160

Parts commonly replaced

  • Main PCB
  • Jumper links
Full explanation for E.02 – .20
Showing 51–60 of 129
E.02 – .21

Your boiler's internal control settings have been accidentally changed or the circuit board is misconfigured.

High Engineer only £90-180

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Control Board Jumper Links
Full explanation for E.02 – .21
E.02 – .47

Your boiler is having trouble communicating with an external control, like your thermostat or timer, due to a connection or wiring issue.

High Engineer only £90-180

Parts commonly replaced

  • External Timer
  • Room Thermostat
  • Wiring Loom

Related codes

Full explanation for E.02 – .47
E.02 – .48

Your boiler is having trouble communicating with your thermostat or wireless controls, meaning it cannot receive instruction to turn on.

High DIY-safe £80-220

What to check first

  1. Check if your wireless thermostat has run out of batteries and replace them if necessary.
  2. Ensure the thermostat is within range of the boiler and has not been moved too far away.
  3. Try resetting the boiler and the external control unit to re-establish a connection.

Parts commonly replaced

  • Thermostat batteries
  • RF Receiver unit
  • Wireless Room Thermostat
Full explanation for E.02 – .48
E.04 – .00

Your boiler has lost its connection to the component that controls the fuel supply, meaning it cannot safely light the flame for heating or hot water.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Main PCB (Control board)
  • Wiring harness

Related codes

Full explanation for E.04 – .00
E.04 – .02

Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit.

High Engineer only £90-160

Parts commonly replaced

  • Flow Temperature Sensor (NTC Thermistor)
  • Wiring Harness

Related codes

Full explanation for E.04 – .02
E.04 – .03

Your boiler has shut down because the water inside is getting too hot too quickly, usually because it isn't moving through the system properly.

High DIY-safe £150-£350

What to check first

  1. Check that the boiler pressure is between 1.0 and 1.5 bar
  2. Ensure all radiator valves and isolation valves under the boiler are fully open
  3. Bleed any air out of your radiators

Parts commonly replaced

  • Central heating pump
  • Flow temperature sensor
  • Main heat exchanger (flushing)

Related codes

Full explanation for E.04 – .03
E.04 – .04

Your boiler has detected a problem with the sensor that monitors exhaust gases, and it has shut down for safety purposes.

High Engineer only £100-£180

Parts commonly replaced

  • Flue Temperature Sensor (NTC)
  • Wiring Harness
  • Main Control Board (PCB)
Full explanation for E.04 – .04
E.04 – .05

Your boiler has detected a problem with the sensor that monitors exhaust gas temperatures, causing it to shut down for safety.

High Engineer only £100-180

Parts commonly replaced

  • Flue Temperature Sensor (NTC)
  • Sensor Wiring Harness
Full explanation for E.04 – .05
E.04 – .06

Your boiler has likely overheated or is failing to move water correctly, causing it to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Main Heat Exchanger
  • Circulating Pump
  • Flue Thermistor
  • Temperature Sensor (NTC)
Full explanation for E.04 – .06
Showing 61–70 of 129
E.04 – .08

Your boiler has hit a dangerously high temperature or detected a circulation issue and has locked itself out for safety.

High DIY-safe £100-280

What to check first

  1. Check that the radiator valves and the main boiler valves are fully open.
  2. Ensure the system pressure is between 1.0 and 1.5 bar on the pressure gauge.
  3. Attempt to reset the boiler once it has had 30 minutes to cool down.

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • NTC thermistor (sensor)

Related codes

Full explanation for E.04 – .08
E.04 – .10

Your boiler has failed to ignite, which means it is unable to create a flame to provide heating or hot water.

High DIY-safe £100-£350

What to check first

  1. Check that your gas emergency control valve is in the 'on' position
  2. If you have a pre-payment meter, ensure you have sufficient credit
  3. Try to reset the boiler by turning the selector switch to 'R' for five seconds and then back to the original position

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • PCB (Printed Circuit Board)
  • Flame Sensing Electrode

Related codes

Full explanation for E.04 – .10
E.04 – .12

Your boiler thinks a flame is burning when it shouldn't be, which is usually caused by a sensor error or a problem with the gas supply timing.

High Engineer only £120-350

Parts commonly replaced

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

Related codes

Full explanation for E.04 – .12
E.04 – .13

Your boiler's fan has stopped spinning properly, which means it cannot safely clear away exhaust fumes and has shut down as a precaution.

High Engineer only £250-£450

Parts commonly replaced

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

Related codes

Full explanation for E.04 – .13
E.04 – .17

Your boiler has detected a serious internal communication or hardware failure in the gas management system and has locked out for safety.

High Engineer only £250-450

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)
  • Venturi/Air Unit

Related codes

Full explanation for E.04 – .17
E0

Your boiler has detected an issue with the sensor that reads the temperature of the water, preventing it from heating up correctly for your safety.

High Engineer only £90-160

Parts commonly replaced

  • NTC Temperature Sensor
  • Sensor Wiring Harness

Related codes

Full explanation for E0
E1

Your boiler has become too hot and has shut down as a safety precaution to prevent damage.

High DIY-safe £100-250

What to check first

  1. Turn off the boiler and allow it to cool down completely.
  2. Breathe any trapped air out of your radiators using a radiator key.
  3. Check the boiler pressure gauge and top it up to 1.5 bar if it has dropped.
  4. Reset the boiler by turning the selector switch to 'R' for at least five seconds.

Parts commonly replaced

  • Overheat Thermostat
  • Circulating Pump
  • NTC Thermistor

Related codes

Full explanation for E1
E2

Your boiler is struggling to push water around your radiators, usually because of trapped air or a blockage.

High DIY-safe £80-250

What to check first

  1. Turn off your heating and allow the radiators to cool down.
  2. Use a radiator key to bleed all radiators, starting from the lowest floor.
  3. Check your boiler pressure gauge and use the filling loop to top it up to 1.5 bar if it has dropped.

Parts commonly replaced

  • Circulation Pump
  • Auto Air Vent
  • Main Heat Exchanger (if scaled)

Related codes

Full explanation for E2
E3

Your boiler's electronic control centre has developed an internal error and can no longer safely operate the system.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
Full explanation for E3
E4

Your boiler has failed to light the flame, which is often caused by trapped air in the system or a temporary interruption in the gas supply.

High DIY-safe £100-280

What to check first

  1. Check if your gas meter is topped up and other gas appliances are working.
  2. Bleed your radiators using a radiator key to remove any trapped air.
  3. Press and hold the Reset button for five seconds to restart the boiler.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E4
Showing 71–80 of 129
E09

Your boiler has detected a communication problem between its main control board and the gas valve, meaning it cannot safely ignite to provide heat or hot water.

High Engineer only £120-£350

Parts commonly replaced

  • Gas valve wiring harness
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E09
E10

Your boiler is having trouble communicating with the optional sensor used to measure the temperature outside, meaning it might struggle to adjust your heating efficiency correctly.

Low Engineer only £60-140

Parts commonly replaced

  • Outdoor temperature sensor
  • External wiring link

Related codes

Full explanation for E10
E12

Your boiler has detected that water is not circulating correctly through the system, preventing it from firing up safely.

High DIY-safe £100-250

What to check first

  1. Check that your central heating valves (under the boiler) are fully open
  2. Ensure all radiator valves (TRVs) are turned to maximum
  3. Inspect the boiler pressure gauge and top up to 1.5 bar if it is low
  4. Restart the boiler using the reset button

Parts commonly replaced

  • Differential pressure switch
  • Circulating pump
  • Diaphragm rubber

Related codes

Full explanation for E12
E13

Your boiler has detected that a internal water sensor is stuck in the 'on' position even though the pump has stopped moving water.

High Engineer only £120-220

Parts commonly replaced

  • Differential pressure switch
  • Microswitch
  • Pump

Related codes

Full explanation for E13
E15

Your boiler has detected an internal electrical problem between the control board and the gas valve, preventing it from firing up safely.

High Engineer only £180-£450

Parts commonly replaced

  • Gas Valve
  • PCB (Main Control Board)
  • Wiring Harness

Related codes

Full explanation for E15
E20

Your boiler has lost its connection to the sensor that measures the temperature of the water for your radiators, meaning it cannot heat your home safely.

High Engineer only £90-160

Parts commonly replaced

  • Central Heating (Flow) NTC Thermistor
  • Connecting wiring harness

Related codes

Full explanation for E20
E28

Your boiler has detected a safety issue with how it disposes of waste gases or a blockage in its drainage system, causing it to shut down to prevent damage.

High DIY-safe £100-280

What to check first

  1. Check the white plastic condensate pipe outside for signs of freezing or blockages
  2. Inspect the external flue terminal to ensure it is not obstructed by debris or plants
  3. Reset the boiler by turning the selector switch to 'R' for five seconds

Parts commonly replaced

  • Flue NTC Sensor
  • Air Pressure Switch
  • Condensate Trap

Related codes

Full explanation for E28
E40

Your boiler has detected an issue with the sensor that monitors the temperature of the water returning from your radiators.

High Engineer only £90-160

Parts commonly replaced

  • Central heating return NTC sensor
  • Wiring harness

Related codes

Full explanation for E40
E50

Your boiler has detected a problem with the sensor that measures hot water temperature, which means it may not be able to heat your taps correctly.

Medium Engineer only £90-160

Parts commonly replaced

  • Hot water NTC thermistor
  • Connecting wiring harness

Related codes

Full explanation for E50
E53

Your boiler has detected that it is not burning gas correctly, which could be caused by an obstruction in the external exhaust pipe.

Emergency DIY-safe £100-250

What to check first

  1. Check the external flue terminal (exhaust pipe) for any visual obstructions like bird nests, debris, or snow.
  2. Carefully remove any external blockages if safe to reach from the ground.
  3. Reset the boiler using the control knob once any external blockages are cleared.
  4. If the error persists or no external blockage is found, turn off the gas supply and call a Gas Safe engineer.

Parts commonly replaced

  • Gas Valve
  • Fan
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E53
Showing 81–90 of 129
E54

Your boiler is having trouble detecting when you turn on your hot taps, which may result in lukewarm or no hot water at all.

Medium Engineer only £90-180

Parts commonly replaced

  • DHW Flow Sensor
  • Flow Turbine
  • Wiring Harness

Related codes

Full explanation for E54
E55

Your boiler has lost its settings and needs to be professionally configured to ensure the gas is burning correctly and safely.

High Engineer only £100-250

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E55
E78

Your boiler has lost the ability to monitor its own water pressure, meaning it has shut down to prevent damage.

High Engineer only £140-£200

Parts commonly replaced

  • Water pressure sensor
  • Sensor wiring harness

Related codes

Full explanation for E78
E83/E84/E85/E86/E87

Your boiler's electronic brains have lost contact with each other, meaning the unit cannot receive instructions to provide heating or hot water.

High Engineer only £180-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness
  • Low Voltage Cable

Related codes

Full explanation for E83/E84/E85/E86/E87
E92

Your boiler has detected an issue while trying to automatically adjust its burner settings and has shut down for safety.

High Engineer only £120-350

Parts commonly replaced

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

Related codes

Full explanation for E92
E100

Your boiler’s internal computer has lost track of the time or date, which is preventing its scheduled heating cycles from starting correctly.

High DIY-safe £0-280

What to check first

  1. Locate the user control panel on the front of the boiler
  2. Navigate to the time and date settings menu
  3. Update the current time and date then press the 'Reset' button

Parts commonly replaced

  • Printed Circuit Board (PCB)

Related codes

Full explanation for E100
E109

Your boiler is struggling to move water through the system effectively, which is causing it to shut down to prevent overheating.

High DIY-safe £150-£350

What to check first

  1. Check that the boiler pressure is between 1.0 and 1.5 bar on the gauge
  2. Ensure all radiator valves and isolation valves are fully open
  3. Gently bleed your radiators to remove any trapped air pockets

Parts commonly replaced

  • Central heating pump
  • Pump head
  • Main heat exchanger (flushing)

Related codes

Full explanation for E109
E110

Your boiler has likely overheated, causing a safety sensor to shut the system down to prevent damage.

High DIY-safe £100-280

What to check first

  1. Wait 30 minutes for the boiler to cool down fully.
  2. Check that your radiator valves are open and not blocked by furniture.
  3. Check the boiler pressure gauge and top it up to 1.5 bar if it is too low.
  4. Turn the selector switch to the 'R' (Reset) position for at least five seconds and then release it.

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Water Pressure Sensor

Related codes

Full explanation for E110
E117

Your boiler has stopped working because there is too much water pressure in the system, which is usually caused by overfilling the boiler or a leaking filling valve.

High DIY-safe £80-160

What to check first

  1. Check that the filling loop valves are tightly closed
  2. Turn off the boiler and allow it to cool
  3. Slowly bleed water from a radiator using a bleed key into a cloth or container
  4. Monitor the pressure gauge until it returns to between 1 and 1.5 bar

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for E117
E118

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

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver braided hose with small tap handles) underneath your boiler.
  2. Slowly open both taps to allow water into the system, watching the pressure gauge on the boiler front.
  3. Close both taps tightly once the gauge reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for E118
Showing 91–100 of 129
E119

Your boiler has stopped working because the water pressure is too low for the system to run safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually two silver braided hoses under the boiler)
  2. Open the valves slowly until you hear water entering the system
  3. Watch the pressure gauge and close the valves once it reaches between 1.0 and 1.5 bar

Parts commonly replaced

  • Filling loop
  • Water pressure switch
  • Expansion vessel

Related codes

Full explanation for E119
E125

Your boiler has detected that water is not moving through the system properly, which is causing it to overheat and shut down for safety.

High Engineer only £180-£450

Parts commonly replaced

  • Circulation pump
  • Diverter valve motor
  • Main heat exchanger (flushing)

Related codes

Full explanation for E125
E128

Your boiler is struggling to keep its burner lit and has shut down after several failed attempts to maintain a steady flame.

High Engineer only £120-350

Parts commonly replaced

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

Related codes

Full explanation for E128
E129

Your boiler is struggling to keep a steady flame while it tries to automatically adjust its settings, causing it to shut down for safety.

High Engineer only £100-£250

Parts commonly replaced

  • Flame sensing electrode
  • Ignition lead
  • Gas valve

Related codes

Full explanation for E129
E130

Your boiler has shut down because it thinks the exhaust gases are getting too hot, which is a safety measure to prevent damage.

High Engineer only £100-220

Parts commonly replaced

  • Flue NTC Thermistor
  • Main Heat Exchanger cleaning
  • PCB

Related codes

Full explanation for E130
E131

Your boiler has shut down because the exhaust gases have become too hot, which is a safety measure to prevent damage to the system.

High Engineer only £120-£350

Parts commonly replaced

  • Flue Thermistor
  • Heat Exchanger
  • Main PCB

Related codes

Full explanation for E131
E133

Your boiler has tried to ignite but cannot get a steady gas supply or sense a flame, which means it has locked itself out for safety.

High DIY-safe £100-£250

What to check first

  1. Check if your gas meter has credit (if on a prepayment meter)
  2. Check if other gas appliances, like a hob, are working to confirm gas supply
  3. Rotate the selector switch to the 'R' (Reset) position for five seconds and release
  4. If it is freezing outside, check if your white plastic condensate pipe is frozen and thaw it with warm water

Parts commonly replaced

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

Related codes

Full explanation for E133
E134

Your boiler has tried to ignite several times but cannot detect a flame, causing it to shut down for safety.

High DIY-safe £120-£350

What to check first

  1. Check that your gas prepayment meter has credit
  2. Ensure other gas appliances (like a hob) are working to confirm gas supply
  3. Press the Reset button for five seconds

Parts commonly replaced

  • Gas valve
  • Ignition electrode
  • Spark generator
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E134
E135

Your boiler has lost its connection to the gas supply due to an internal technical fault and cannot stay lit.

High Engineer only £150-450

Parts commonly replaced

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

Related codes

Full explanation for E135
E154

Your boiler has noticed that water is not circulating correctly or the temperature sensors are giving conflicting readings.

High Engineer only £120-£250

Parts commonly replaced

  • Flow temperature sensor
  • Return temperature sensor
  • Circulation pump

Related codes

Full explanation for E154
Showing 101–110 of 129
E160

Your boiler has detected a problem with the fan that clears exhaust gases, preventing it from starting up safely.

High Engineer only £180-£400

Parts commonly replaced

  • Extraction Fan
  • Fan Wiring Harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E160
E160 / E161

Your boiler has detected a problem with the fan that clears out exhaust gases, meaning it cannot start up safely for heating or hot water.

High Engineer only £200-£450

Parts commonly replaced

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

Related codes

Full explanation for E160 / E161
E163

Your boiler's temperature sensor for hot water has developed a fault or electrical short, meaning the system cannot accurately measure how hot the water is.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW NTC Sensor
  • Wiring harness connectors

Related codes

Full explanation for E163
E164

Your boiler is having trouble monitoring its internal water pressure, which means it cannot operate safely and has shut down.

High Engineer only £140-£200

Parts commonly replaced

  • Pressure sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for E164
E167

Your boiler’s internal computer has encountered a software error or a technical glitch and cannot communicate correctly with the other parts of the system.

High Engineer only £250-£450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal wiring harness

Related codes

Full explanation for E167
E168

Your boiler has experienced an internal communication error where the main control board has frozen or crashed, preventing it from heating your home.

High DIY-safe £250-£450

What to check first

  1. Turn the selector switch to the reset position and hold for 5 seconds
  2. Switch off the electrical power supply to the boiler at the fused spur for 60 seconds
  3. Turn the power back on and attempt to restart the heating

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • External Surge Protector

Related codes

Full explanation for E168
E193

Your boiler has detected that water is not moving through the system properly before the burner ignites, often due to a blockage or trapped air.

High Engineer only £150-£350

Parts commonly replaced

  • Circulation Pump
  • Automatic Air Vent
  • Pump Lead/Cable

Related codes

Full explanation for E193
E270

Your boiler has detected that water isn't moving through the system properly, which is causing it to overheat too quickly.

High DIY-safe £100-£350

What to check first

  1. Check that your system pressure is between 1.0 and 1.5 bar
  2. Ensure all radiator valves and isolation valves under the boiler are fully open
  3. Bleed all radiators to remove trapped air that might be blocking flow

Parts commonly replaced

  • Circulation pump
  • Main heat exchanger
  • Flow/Return thermistors

Related codes

Full explanation for E270
E317

Your boiler has detected an issue with the electrical power timing coming into the unit, which means it cannot operate correctly for safety reasons.

High Engineer only £150-£350

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • In-line surge protector

Related codes

Full explanation for E317
E321

Your boiler's hot water sensor has failed or is disconnected, meaning the system cannot tell how hot your water is and has stopped heating it for safety.

Medium Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC thermistor
  • Connecting wiring harness

Related codes

Full explanation for E321
Showing 111–120 of 129
E384

Your boiler thinks it sees a flame even though it hasn't started the ignition process yet, which is causing it to shut down for safety.

High Engineer only £120-300

Parts commonly replaced

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

Related codes

Full explanation for E384
E385

Your boiler is struggling to operate because it is receiving an unstable or low supply of electricity from your home's power network.

High DIY-safe £100-350

What to check first

  1. Check if other electrical appliances in your home are flickering or behaving strangely.
  2. Turn the boiler off and back on at the main isolation switch (fused spur) to see if the fault clears.
  3. Ensure your electricity meter has credit if you are on a pay-as-you-go tariff.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External voltage stabilizer

Related codes

Full explanation for E385
E430

Your boiler is temporarily checking if there is enough water pressure in the system to operate safely.

Low DIY-safe £0-120

What to check first

  1. Check the pressure gauge on the front of the boiler
  2. If the pressure is below 1.0 bar, use the filling loop to top it up to 1.5 bar
  3. Restart the boiler to see if the code clears

Parts commonly replaced

  • Water pressure sensor
  • Filling loop valve

Related codes

Full explanation for E430
H.01 – .00

Your boiler has lost its internal connection to the part that controls the gas flow, meaning it cannot ignite to provide heating or hot water.

High Engineer only £160-450

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for H.01 – .00
H.01 – .05

Your boiler is overheating because water isn't moving through the system quickly enough to take the heat away.

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar on the gauge)
  3. Bleed all radiators to remove trapped air that might be blocking circulation

Parts commonly replaced

  • Circulation Pump
  • Flow/Return Temperature Sensors (NTC)
  • Main Heat Exchanger (if scaled up)

Related codes

Full explanation for H.01 – .05
H.01 – .08

Your boiler is overheating or water is not moving through the system fast enough to stay at a safe temperature.

High DIY-safe £120-300

What to check first

  1. Check that your radiator valves (TRVs) are open and not turned to zero.
  2. Ensure your boiler pressure is between 1.0 and 1.5 bar on the gauge.
  3. Bleed your radiators to remove any trapped air that might be blocking circulation.

Parts commonly replaced

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

Related codes

Full explanation for H.01 – .08
H.01 – .14

Your boiler has detected that it is getting too hot too quickly, usually because water isn't moving through the system properly.

High DIY-safe £120-350

What to check first

  1. Check that your radiator valves are open
  2. Ensure your system water pressure is between 1.0 and 1.5 bar
  3. Bleed your radiators to remove any trapped air
  4. Reset the boiler to see if the temporary fault clears

Parts commonly replaced

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

Related codes

Full explanation for H.01 – .14
H.01 – .18

Your boiler is struggling to move water through the system, which is likely caused by low pressure or a blockage.

High DIY-safe £100-£350

What to check first

  1. Check the pressure gauge and top it up to 1.5 bar using the filling loop
  2. Ensure all radiator valves are fully open
  3. Bleed your radiators to remove any trapped air

Parts commonly replaced

  • Circulation Pump
  • NTC Temperature Sensor
  • Central Heating Filter

Related codes

Full explanation for H.01 – .18
H.01 – .21

Your boiler is stopping itself because the water is heating up too quickly, which usually means the hot water isn't flowing through the system properly.

Medium DIY-safe £90-280

What to check first

  1. Check that your main water stop tap is fully open
  2. Ensure all isolation valves under the boiler are in the open position
  3. Switch the boiler off and back on again to see if the temporary fault clears

Parts commonly replaced

  • DHW Temperature Sensor (NTC)
  • Plate Heat Exchanger
  • Circulation Pump

Related codes

Full explanation for H.01 – .21
H.02 – .02

Your boiler has lost its programmed settings and currently doesn't know how to operate, often occurring after a power cut or a part replacement.

High Engineer only £100-£350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Parameter Key

Related codes

Full explanation for H.02 – .02
Showing 121–129 of 129
H.02 – .03

Your boiler is confused by its internal setup settings and cannot start up properly until they are corrected.

High Engineer only £90-180

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for H.02 – .03
H.02 – .04

Your boiler's internal computer has become confused by its own settings and needs a simple electronic refresh to resume normal operation.

Low DIY-safe £0-120

What to check first

  1. Locate the selector switch on the front of the boiler.
  2. Turn the switch to the 'R' (Reset) position and hold for at least 5 seconds.
  3. Return the switch to its original position and wait for the boiler to restart.

Parts commonly replaced

  • None (usually software reset)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for H.02 – .04
H.02 – .06

Your boiler has detected that the water pressure is too low or unstable, often caused by a leak or a need to top up the system.

High DIY-safe £0-180

What to check first

  1. Check the pressure gauge on the front of the boiler; it should ideally be between 1 and 1.5 bar.
  2. Locate the filling loop (usually a silver braided hose with two black taps) underneath the boiler.
  3. Slowly open both taps until you hear water moving and the pressure needle reaches 1.5 bar, then close them tightly.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for H.02 – .06
H.03 -.00

Your boiler is struggling to communicate with its internal temperature sensors, which is preventing it from heating up safely.

High Engineer only £90-180

Parts commonly replaced

  • Central Heating NTC Sensor
  • Flue Thermistor
  • Wiring Harness

Related codes

Full explanation for H.03 -.00
H.03 – .01

Your boiler's main control board has lost connection with its internal systems, meaning it cannot send or receive the proper instructions to heat your water.

High Engineer only £280-450

Parts commonly replaced

  • Main PCB
  • Wiring Harness
  • Ignition Electrode

Related codes

Full explanation for H.03 – .01
H.03 – .02

Your boiler has lost its flame while it was running, which means it cannot heat your water or radiators and has shut down for safety.

High Engineer only £120-£350

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Spark generator
  • PCB

Related codes

Full explanation for H.03 – .02
OFF OFF OFF

Your boiler is not receiving any electricity, which means the display and all heating functions are completely powered down.

High DIY-safe £60-220

What to check first

  1. Check if your home's main electrical consumer unit has a tripped circuit breaker
  2. Ensure the boiler's fused spur switch (usually located near the boiler) is turned on
  3. Check if other appliances in the house have power to rule out a local power cut

Parts commonly replaced

  • Internal Glass Fuse
  • Printed Circuit Board (PCB)
  • Fused Spur
Full explanation for OFF OFF OFF
ON OFF ON

Your boiler has tried to light several times but cannot establish a flame, meaning it has temporarily shut down for safety.

High DIY-safe £100-350

What to check first

  1. Check that your gas prepayment meter has credit
  2. Ensure other gas appliances (like a hob) are working to confirm gas supply
  3. Reset the boiler by turning the selector knob to the 'R' position for at least 5 seconds
  4. Check for frozen outdoor condensate pipes during very cold weather

Parts commonly replaced

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

Related codes

Full explanation for ON OFF ON
ON ON ON

Your boiler has detected an internal electrical communication problem that is preventing it from running safely.

High Engineer only £120-£350

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for ON ON ON