Alpha E-Tec Plus 28 Fault codes & diagnostics

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

Combi Natural Gas 28 kW 2019-present

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Severity at a glance

Each cell = one fault code. Hover to identify.
7 Emergency 69 High 5 Medium 3 Low
Just want the most common Alpha E-Tec Plus 28 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 84 documented codes

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01

Your boiler has failed to light the flame needed to generate heat, and it will keep trying to restart until the fault is cleared.

High DIY-safe £120-250

What to check first

  1. Check if other gas appliances like a hob are working to ensure gas is reaching the property
  2. Check that your gas meter has credit if you use a prepay meter
  3. Press and hold the 'R' reset button for 2 seconds to see if the boiler restarts
  4. Check that the condensate pipe (typically a white plastic pipe leading outside) isn't frozen in cold weather

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for 01
02

Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent any damage or danger.

High DIY-safe £120-250

What to check first

  1. Check that your radiator valves are open and not turned off.
  2. Wait 30 minutes for the system to cool down completely.
  3. Press and hold the 'R' reset button for a few seconds to restart the boiler.

Parts commonly replaced

  • NTC sensor
  • Pump
  • Diverter valve
  • Heat exchanger

Related codes

Full explanation for 02
03

Your boiler has automatically shut down because the exhaust gases escaping through your flue pipe have become dangerously hot, suggesting a potential internal blockage or a cooling issue.

Emergency Engineer only £150-300

Parts commonly replaced

  • Flue sensor
  • Primary heat exchanger
  • Pump

Related codes

Full explanation for 03
04

Your boiler has lost the secure electrical connection required to safely control its gas supply, so it has shut down to prevent any unsafe operation.

High Engineer only £150-250

Parts commonly replaced

  • Gas valve wiring harness
  • Gas valve assembly
  • Printed circuit board (PCB)

Related codes

Full explanation for 04
05

Your boiler is struggling to detect the temperature of the water flowing through your heating system, which is preventing it from heating your home properly.

High Engineer only £150-250

Parts commonly replaced

  • NTC sensor
  • Wiring harness

Related codes

Full explanation for 05
06

Your boiler is struggling to detect the temperature of the water being heated for your taps, which means it has stopped providing hot water to prevent overheating.

High Engineer only £120-200

Parts commonly replaced

  • DHW NTC thermistor sensor
  • Wiring harness

Related codes

Full explanation for 06
08

Your boiler has attempted to restart itself too many times after encountering a series of underlying issues and has now locked itself out for safety.

High DIY-safe £120-250

What to check first

  1. Turn the power to the boiler off at the fused spur switch (the wall switch).
  2. Wait for 30 seconds.
  3. Turn the power back on to clear the lockout memory and allow a further reset.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
  • Flame sensor

Related codes

Full explanation for 08
10

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 external filling loop, usually two silver valves connected by a braided metal hose underneath the boiler.
  2. Open the valves slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Close both valves firmly and ensure they are fully tightened.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge

Related codes

Full explanation for 10
12

Your boiler's computer system is currently confused about how your internal heating setup is configured, which prevents it from operating safely.

High Engineer only £120-250

Parts commonly replaced

  • PCB (Printed Circuit Board)
Full explanation for 12
15

Your boiler's computer is confused because its internal settings do not match how the system is physically connected or configured.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 15
Showing 11–20 of 84
16

Your boiler has stopped working because it cannot properly circulate the air it needs to burn gas safely.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 16
20

Your boiler has detected a flame signal when it shouldn't be there, so it has purposefully shut itself down to keep your home safe.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Flame rectification probe
  • Gas valve

Related codes

Full explanation for 20
23

Your boiler's computer is confused because it has detected a mismatch in its internal settings, meaning it cannot safely start your heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Main Control PCB
  • Configuration Key

Related codes

Full explanation for 23
24

Your boiler's control panel has detected that one of its buttons is permanently held down or jammed, preventing the system from operating normally.

High DIY-safe £100-200

What to check first

  1. Switch off the boiler power at the fused spur or mains switch.
  2. Carefully inspect the control panel buttons or digital interface for any dirt, debris, or sticky residue that might be holding a button in place.
  3. Gently press or wiggle the buttons to see if they can be un-stuck, then power the boiler back on to see if the code clears.

Parts commonly replaced

  • User interface (UI) board
  • Control panel assembly membrane

Related codes

Full explanation for 24
25

Your boiler's computer has encountered an internal error and cannot communicate properly, which means it will not be able to provide heating or hot water.

High Engineer only £200-350

Parts commonly replaced

  • Printed Circuit Board (PCB)

Related codes

Full explanation for 25
27

Your boiler is struggling to pump water around your heating system effectively, causing it to overheat and shut down to protect itself.

High DIY-safe £150-300

What to check first

  1. Check that all radiator valves are fully open to allow water to flow.
  2. Ensure your system water pressure is between 1.0 and 1.5 bar on the gauge.
  3. Try resetting the boiler by turning the selector switch to 'R' for a few seconds.

Parts commonly replaced

  • Central heating pump
  • System filter
  • Diverter valve

Related codes

Full explanation for 27
29

Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, meaning it has safely shut down to prevent potential overheating.

High Engineer only £120-220

Parts commonly replaced

  • Flue gas sensor
  • Wiring harness
Full explanation for 29
31

Your boiler has lost its connection to your smart thermostat or wall controller, meaning it does not know when to turn the heating on.

Medium DIY-safe £120-250

What to check first

  1. Check if the batteries in your Alpha Climatic thermostat need replacing.
  2. Ensure the thermostat is within range of the boiler and has not been moved too far away.
  3. Try resetting the boiler by turning the selector switch to 'RESET' for a few seconds.

Parts commonly replaced

  • Alpha Climatic central unit
  • PCB
  • Wiring loom
Full explanation for 31
36

Your boiler's electronic control system is showing an error that doesn't apply to this specific model, suggesting a potential software glitch or a loose internal communication wire.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 36
37

Your boiler is struggling because it is not receiving enough electricity from your home's mains power supply.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
  • External power supply/fused spur

Related codes

Full explanation for 37
Showing 21–30 of 84
38

Your boiler is struggling to keep its flame lit, so it is automatically turning itself off and trying to restart to keep you safe.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Ionisation probe
  • Gas valve

Related codes

Full explanation for 38
43

Your boiler is repeatedly shutting down because it cannot consistently keep the flame lit, often caused by strong winds affecting the flue outside.

High DIY-safe £120-250

What to check first

  1. Check if other gas appliances (like a hob) are working to ensure gas supply
  2. Press and hold the reset button for several seconds
  3. Check if the outdoor flue pipe is blocked by debris or affected by very strong winds

Parts commonly replaced

  • Flame rectification electrode
  • Ignition lead
  • Gas valve

Related codes

Full explanation for 43
45

Your boiler has detected that the water is heating up or circulating much faster than it should, which often points to a blockage or a pump issue.

High DIY-safe £150-300

What to check first

  1. Check that at least two or three radiator valves are fully open
  2. Ensure your central heating pump is running and not stuck
  3. Bleed all radiators to remove trapped air that might be blocking water flow

Parts commonly replaced

  • Central heating pump
  • Plate heat exchanger
  • System filter

Related codes

Full explanation for 45
46

Your boiler has stopped working because a safety link that tells the unit it is safe to operate has been disconnected or triggered.

High Engineer only £100-200

Parts commonly replaced

  • External safety link
  • External safety device

Related codes

Full explanation for 46
47

Your boiler is getting too hot inside its exhaust path, so it has automatically turned down its power to prevent any internal damage.

High Engineer only £150-300

Parts commonly replaced

  • Flue gas sensor
  • Heat exchanger
  • PCB

Related codes

Full explanation for 47
51

Your boiler has lost its wireless connection to your room thermostat or controller, meaning it doesn't know when to turn the heating on or off.

Medium DIY-safe £100-200

What to check first

  1. Check if the batteries in your remote thermostat controller are dead and replace them if necessary.
  2. Switch the boiler off at the fused spur for 60 seconds, then turn it back on to force a signal resync.
  3. Ensure there are no large metal objects or new electronic devices placed between the boiler and the thermostat causing interference.

Parts commonly replaced

  • Climatic RF receiver module
  • RF transmitter unit
Full explanation for 51
59

Your boiler is struggling because the electricity supply coming from your mains is not stable or is fluctuating outside of the normal range it expects.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness
Full explanation for 59
60

Your boiler has stopped circulating water because the internal pump that pushes water around your heating system is currently not spinning.

High Engineer only £180-350

Parts commonly replaced

  • Central heating pump
  • Wiring harness
  • PCB

Related codes

Full explanation for 60
61

Your boiler is struggling to push water around your heating system because there is trapped air bubbles inside the pump or a blockage in the pipes.

High DIY-safe £90-180

What to check first

  1. Check your boiler pressure gauge to ensure it is between 1.0 and 1.5 bar
  2. Bleed all radiators in your home starting from the downstairs and moving upstairs
  3. Top up the system pressure to 1.5 bar using the filling loop if it dropped after bleeding

Parts commonly replaced

  • Central heating pump
  • Automatic air vent
  • System filter

Related codes

Full explanation for 61
62

Your boiler has lost its saved settings for the air and gas mixture and needs to be professionally reconfigured to run safely and efficiently.

High Engineer only £100-200

Parts commonly replaced

  • None - requires software recalibration

Related codes

Full explanation for 62
Showing 31–40 of 84
70

Your boiler is struggling to detect water temperature correctly, which is likely caused by a blocked system, loose wiring, or a faulty sensor prevented it from heating properly.

High DIY-safe £120-250

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. Restart the boiler using the reset button

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness
  • System magnetic filter

Related codes

Full explanation for 70
72

Your boiler's computer has detected a configuration error and needs a reset of its internal operating settings to function correctly.

High Engineer only £100-£200

Parts commonly replaced

  • Main PCB
  • Gas valve

Related codes

Full explanation for 72
73

Your boiler has detected an inconsistent temperature reading between its internal sensors, causing it to shut down for safety.

High Engineer only £150-250

Parts commonly replaced

  • NTC Sensor
  • Wiring harness

Related codes

Full explanation for 73
74

Your boiler has detected a faulty reading from a sensor that monitors the internal temperature, causing it to shut down for safety.

High Engineer only £150-250

Parts commonly replaced

  • Safety NTC sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for 74
75

Your boiler is struggling to accurately read its own internal water temperatures because its primary thermometers are likely sending conflicting or faulty signals.

High Engineer only £120-220

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring Harness

Related codes

Full explanation for 75
76

Your boiler is struggling to read its own internal temperatures because one of its sensors is sending conflicting or invalid signals.

High Engineer only £120-220

Parts commonly replaced

  • NTC Sensor
  • Wiring harness
Full explanation for 76
78

Your boiler has detected an issue with the internal component that manages the gas supply, meaning it has safely switched itself off to prevent unsafe operation.

Emergency Engineer only £150-300

Parts commonly replaced

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

Related codes

Full explanation for 78
79

Your boiler has detected an issue with the internal component that regulates gas flow, meaning it has safely shut itself down to prevent unsafe operation.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 79
80

Your boiler has detected an internal electrical fault preventing it from safely controlling the gas supply, so it has shut down to keep your home safe.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 80
84

Your boiler is struggling because it is not receiving enough gas to work properly, so it has automatically limited its power to stay safe.

High Engineer only £120-250

Parts commonly replaced

  • Gas valve
  • Gas meter regulator
  • Gas supply pipework

Related codes

Full explanation for 84
Showing 41–50 of 84
87

Your boiler has detected an internal issue with the part that manages the gas supply, so it has safely shut itself down to prevent unsafe operation.

High Engineer only £250-450

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
Full explanation for 87
89

Your boiler is struggling to keep a steady flame, causing it to shut down for safety reasons.

High Engineer only £150-350

Parts commonly replaced

  • Flame rectification electrode
  • Gas valve
  • Burner seal
  • PCB

Related codes

Full explanation for 89
90

Your boiler has detected an issue with the flame detection system, forcing a safety shutdown to prevent improper operation.

High Engineer only £150-300

Parts commonly replaced

  • Flame rectification electrode
  • Ignition lead
  • Printed circuit board

Related codes

Full explanation for 90
91

Your boiler is failing to stay lit because it cannot reliably detect the flame needed to produce heat.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Gas valve
  • PCB

Related codes

Full explanation for 91
92

Your boiler's air management system is struggling to function properly and has hit its limit, causing it to stop for safety reasons.

High Engineer only £150-300

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Flue system components

Related codes

Full explanation for 92
93

Your boiler has detected an issue with the flame intensity that falls outside of its normal operating settings, causing it to shut down for safety reasons.

High Engineer only £120-250

Parts commonly replaced

  • Flame rectification electrode
  • Gas valve
  • PCB

Related codes

Full explanation for 93
94

Your boiler has detected an issue with the air or exhaust flow, meaning it cannot safely burn gas, so it has shut down to protect your home.

Emergency Engineer only £150-350

Parts commonly replaced

  • Fan assembly
  • Flue seal
  • Air pressure switch
  • Venturi

Related codes

Full explanation for 94
95

Your boiler is struggling to maintain a steady flame, causing it to shut down for safety reasons.

High Engineer only £150-350

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Gas valve
Full explanation for 95
96

Your boiler has detected an obstruction in the pipe that removes exhaust gases, meaning it cannot safely vent and has shut down to prevent a carbon monoxide hazard.

Emergency Engineer only £120-250

Parts commonly replaced

  • Flue terminal
  • Fan assembly
  • Air pressure switch

Related codes

Full explanation for 96
98

Your boiler's computer system has encountered too many internal errors and has safely locked itself to prevent further issues.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Control wiring harness
Full explanation for 98
Showing 51–60 of 84
CE

Your boiler is receiving an unusual temperature reading from an external sensor, preventing it from heating your home correctly.

Medium Engineer only £120-200

Parts commonly replaced

  • External weather compensation sensor
  • Wiring loom

Related codes

Full explanation for CE
E01

Your boiler has failed to light because it cannot detect a flame, which means your heating and hot water have stopped working.

High DIY-safe £120-250

What to check first

  1. Check if other gas appliances in your home (like a hob) are working to ensure gas is reaching the property
  2. Ensure your gas pre-payment meter (if you have one) has sufficient credit
  3. Press and hold the 'R' reset button for a few seconds to see if the boiler restarts

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Condensate trap

Related codes

Full explanation for E01
E02

Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent any damage or safety issues.

High DIY-safe £120-250

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate
  2. Ensure your system pressure is between 1.0 and 1.5 bar on the front gauge
  3. Press and hold the reset button for a few seconds to restart the boiler

Parts commonly replaced

  • Pump
  • Diverter valve
  • Heat exchanger
  • System filter

Related codes

Full explanation for E02
E03

Your boiler has detected that it is running too hot and has automatically shut down to prevent damage to its internal components.

High Engineer only £120-250

Parts commonly replaced

  • NTC temperature sensor
  • Primary heat exchanger
  • Pump

Related codes

Full explanation for E03
E05

Your boiler has stopped heating because it is struggling to accurately measure the temperature of the water flowing through your radiators.

High Engineer only £120-180

Parts commonly replaced

  • NTC Flow Sensor
  • Wiring harness

Related codes

Full explanation for E05
E06

Your boiler is struggling to detect the temperature of your hot water, which means it has temporarily stopped heating your taps and shower.

High Engineer only £120-200

Parts commonly replaced

  • DHW NTC Sensor
  • Wiring harness

Related codes

Full explanation for E06
E08

Your boiler has stopped working because it has been manually reset too many times following previous errors, and it now requires a professional to unlock the system.

High DIY-safe £100-200

What to check first

  1. Turn the boiler off at the main electrical fused spur switch.
  2. Wait for 30 seconds.
  3. Turn the power back on to clear the temporary lockout memory.

Parts commonly replaced

  • Main PCB

Related codes

Full explanation for E08
E10

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

High DIY-safe £0-120

What to check first

  1. Locate the external filling loop, which is a flexible braided hose underneath your boiler connected to two valves.
  2. Open the valves slowly to allow cold mains water to enter the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Close both valves tightly to prevent over-pressurisation.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Expansion vessel
Full explanation for E10
E15

Your boiler has lost the ability to accurately measure the temperature of the water returning to it, so it has shut down as a precaution to prevent overheating or running inefficiently.

High Engineer only £120-220

Parts commonly replaced

  • Return NTC sensor
  • Wiring harness
Full explanation for E15
E16

Your boiler has stopped working because the mechanical fan that pushes waste gases outside is not spinning correctly.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)
Full explanation for E16
Showing 61–70 of 84
E19

Your boiler has been trying to top up its internal water pressure for too long, suggesting your heating system might have a leak or a faulty filling valve.

High Engineer only £120-250

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Isolation valve

Related codes

Full explanation for E19
E20

Your boiler has detected a flame when it should be switched off, which is a safety lockout preventing the unit from operating.

Emergency Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
  • Flame rectification probe

Related codes

Full explanation for E20
E24

Your boiler has detected that hot water is not flowing through your heating system as efficiently as it should, causing it to shut down to prevent overheating.

High DIY-safe £150-300

What to check first

  1. Check all buttons on the front panel to see if any are stuck in the pressed position
  2. Gently press and release each button several times to ensure they move freely
  3. Switch the boiler off at the fused spur switch, wait 30 seconds, and turn it back on

Parts commonly replaced

  • Circulation pump
  • System filter
  • Plate heat exchanger
Full explanation for E24
E31

Your boiler has lost its digital connection to the wall-mounted remote controller, meaning it cannot receive signals to heat your home or water.

High Engineer only £120-250

Parts commonly replaced

  • Remote control unit
  • PCB
  • Communication wiring harness
Full explanation for E31
E35

Your boiler has detected a flame when it should be turned off, so it has safely shut itself down to prevent any risk.

Emergency Engineer only £150-300

Parts commonly replaced

  • Printed circuit board
  • Gas valve

Related codes

Full explanation for E35
E37

Your boiler is struggling because the electricity supply it is receiving is weaker than it should be.

Medium Engineer only £100-250

Parts commonly replaced

  • Printed circuit board
  • Wiring harness

Related codes

Full explanation for E37
E38

Your boiler has stopped working because it cannot stay lit, meaning your heating and hot water have turned off as a safety precaution.

High DIY-safe £150-300

What to check first

  1. Check that your gas emergency control valve is open
  2. If you have a prepayment meter, check that you have sufficient credit
  3. Press and hold the reset button for several seconds to restart the boiler

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Gas valve

Related codes

Full explanation for E38
E40

Your boiler has detected that the electricity supply coming into your home is not steady enough to run its internal electronics safely.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)

Related codes

Full explanation for E40
E41

Your boiler is repeatedly struggling to keep its internal flame lit, prompting it to shut down for safety reasons.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Condensate trap

Related codes

Full explanation for E41
E42

Your boiler's control panel has detected that one of the buttons on the front display is being held down or is stuck in the pressed position.

Medium DIY-safe £90-180

What to check first

  1. Switch off the power supply to the boiler at the fused spur or mains switch.
  2. Inspect the front control panel buttons to ensure none are visibly depressed or jammed with debris.
  3. Gently press and release each button several times to ensure they move freely and 'click' normally.
  4. Switch the power back on and see if the error clears.

Parts commonly replaced

  • Keypad display interface
  • User control PCB
Full explanation for E42
Showing 71–80 of 84
E43

Your boiler has tried to light its internal flame several times but failed, so it has safely shut itself down to prevent wasting gas.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for E43
E44

Your boiler is failing to ignite because it has not received the necessary signal to open the gas supply, meaning you currently have no heating or hot water.

High Engineer only £150-£300

Parts commonly replaced

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

Related codes

Full explanation for E44
E51

Your boiler is not safely venting fumes because the component responsible for pushing air through the system has stopped working properly.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • PCB
Full explanation for E51
E62

Your boiler has lost its internal settings regarding the type of gas it uses and needs a professional to recalibrate the system before it can safely operate.

High Engineer only £100-200
Full explanation for E62
E72

Your boiler has lost its fine-tuning settings and needs to recalibrate itself to burn gas correctly.

High Engineer only £120-220

Parts commonly replaced

  • Gas valve
  • PCB
Full explanation for E72
E76

Your boiler is having trouble controlling the internal gas flow, which means it has safely shut down to prevent damage or inefficient operation.

High Engineer only £180-300

Parts commonly replaced

  • Gas valve
  • Wiring harness

Related codes

Full explanation for E76
E77

Your boiler has detected an electrical issue related to the component that controls your gas supply, so it has safely shut down to prevent any risk.

Emergency Engineer only £150-250

Parts commonly replaced

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

Related codes

Full explanation for E77
E78

Your boiler is failing to detect the gas valve correctly, which prevents it from safely supplying fuel to light the burner.

High Engineer only £150-250

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • PCB

Related codes

Full explanation for E78
E80

Your boiler has detected an internal error with the mechanism that controls the gas supply, meaning it cannot safely start up to heat your home or water.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
Full explanation for E80
E97

Your boiler has reached its programmed time for a routine annual service and is simply reminding you that a qualified engineer should inspect it soon.

Low Engineer only £90-140

Parts commonly replaced

  • None (Standard service items like seals or electrodes if required)
Full explanation for E97
Showing 81–84 of 84
ERR>07

Your boiler is currently in a manual testing mode used by engineers to check emissions, which is not an actual fault.

Low DIY-safe

What to check first

  1. Locate the 'Reset' or 'Mode' button on your boiler's control panel
  2. Press and hold the button for 3-5 seconds
  3. Wait for the display to return to the normal temperature reading or standby screen
Full explanation for ERR>07
ERR>CM

Your boiler has lost communication with its external thermostat or smart control system, causing it to shut down for safety.

High DIY-safe £120-250

What to check first

  1. Check if the batteries in your thermostat need replacing
  2. Ensure the external control unit is properly docked or plugged in
  3. Turn the boiler power off and on again at the fused spur to reset the connection

Parts commonly replaced

  • External thermostat
  • Connection wiring
  • PCB
Full explanation for ERR>CM
F0

Your boiler's electronic settings do not match the physical flue pipe installed, needing a quick adjustment to confirm the pipe length is set correctly for your home.

High Engineer only £90-150
Full explanation for F0
Sr

Your boiler has reached its scheduled annual service interval and is simply reminding you that it is time for a routine safety check.

Low Engineer only £90-130

Parts commonly replaced

  • None (Standard service items like seals or gaskets if required)
Full explanation for Sr