Vokera Easi-Heat 25 Fault codes & diagnostics

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

Combi Natural Gas 25 kW 2015-2022 Discontinued

Replaced by: Easi-Heat Plus

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
60 High 19 Medium 7 Low
Just want the most common Vokera Easi-Heat 25 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 86 documented codes

Tap any card for details

01

Your boiler has failed to ignite and has locked itself out as a safety precaution.

High DIY-safe £90-280

What to check first

  1. Check if your gas supply is turned on and other gas appliances are working
  2. Rotate the mode selector switch to the 'Reset' position and wait for 10 seconds
  3. Return the selector switch to the original position and wait for the boiler to restart

Parts commonly replaced

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

Related codes

Full explanation for 01
1x

Your boiler is unable to light the gas or cannot tell that the flame is lit, so it has shut down for safety.

High DIY-safe £100-280

What to check first

  1. Check if other gas appliances, like a hob, are working to ensure gas is reaching the property
  2. Check your gas meter credit or ensuring the external gas valve is open
  3. Press the 'Reset' button on the control panel once to see if the boiler restarts

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
  • PCB

Related codes

Full explanation for 1x
02

Your boiler has likely stopped working because it has overheated or detected a safety limit issue that it cannot automatically reset.

High DIY-safe £100-250

What to check first

  1. Locate the mode selector switch on the front panel
  2. Turn the switch to the 'OFF/RESET' position and wait for a few seconds
  3. Turn the switch back to either the 'Hot Water' or 'Heating and Hot Water' position

Parts commonly replaced

  • Overheat Thermostat
  • Temperature Sensor (NTC)
  • Circulation Pump

Related codes

Full explanation for 02
2x

Your boiler has detected an internal electrical connection issue that is preventing it from running safely.

High Engineer only £90-250

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)
  • Ignition electrode

Related codes

Full explanation for 2x
03

Your boiler has failed to ignite or has lost its flame multiple times, causing the system to lock itself out for safety.

High Engineer only £120-280

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Electrode
  • Gas Valve
  • PCB

Related codes

Full explanation for 03
3x

Your boiler has detected a problem with how it vents exhaust gases or manages air flow, causing it to shut down for safety.

High Engineer only £100-280

Parts commonly replaced

  • Fan
  • Air Pressure Switch
  • Venturi Tube
  • Flue Seals

Related codes

Full explanation for 3x
04

Your boiler has failed to ignite or stay lit after several attempts and requires a manual reset and investigation by a professional.

High Engineer only £100-£250

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Electrode
  • Gas Valve
  • PCB

Related codes

Full explanation for 04
4x

Your boiler has detected that the water pressure is too low for it to operate safely and has shut down to protect the system.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver braided hose under the boiler).
  2. Slowly open the valve or valves 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.
  4. Press the 'Reset' button on the control panel to restart the boiler.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for 4x
05

Your boiler has detected an issue with the sensor that monitors the water temperature inside your unit, which has caused it to stop running for safety.

High Engineer only £90-160

Parts commonly replaced

  • Primary NTC thermistor
  • Sensor wiring harness

Related codes

Full explanation for 05
5x

Your boiler's central computer has encountered an internal error and can no longer control the heating or hot water safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 5x
Showing 11–20 of 86
06

Your boiler has failed to ignite after several attempts and has locked itself out for safety.

High DIY-safe £100-250

What to check first

  1. Check that your gas emergency control valve is open and you have credit on your meter.
  2. Check if other gas appliances in your home are working correctly.
  3. Press the reset button (turn the selector switch to the 'R' position for a few seconds and then back to 'On').

Parts commonly replaced

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

Related codes

Full explanation for 06
6x

Your boiler has detected a fault with the temperature sensor that controls your hot water, meaning your water may not reach the correct temperature or might not heat up at all.

Medium Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC Thermistor
  • Wiring harness

Related codes

Full explanation for 6x
07

Your boiler has shut down completely because it reached the maximum number of failed attempts to fix an underlying problem.

High DIY-safe £100-350

What to check first

  1. Turn the mode selector switch to 'OFF/RESET' for 5 seconds
  2. Turn the dial back to the 'Hot Water' or 'Heating' position
  3. Monitor the display to see if a different fault code (like 01 or 03) appears immediately after resetting

Parts commonly replaced

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

Related codes

Full explanation for 07
7x

Your boiler has detected that the water temperature in your central heating pipes is getting too hot or is not flowing correctly.

High Engineer only £90-180

Parts commonly replaced

  • Central Heating NTC Sensor
  • Circulation Pump
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 7x
08

Your boiler has detected an internal electronic error or a communication failure that requires a manual reset or professional diagnostic check.

High DIY-safe £100-£350

What to check first

  1. Turn the mode selector switch to the 'OFF/RESET' position.
  2. Wait approximately 10 seconds.
  3. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water'.
  4. If the code persists after three reset attempts, call a Gas Safe engineer.

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring loom connections

Related codes

Full explanation for 08
8x

Your boiler's main internal computer has developed a malfunction and can no longer control the heating system safely.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 8x
09

Your boiler has failed to fire up or complete its safety checks after several attempts and has now locked itself out for safety.

High DIY-safe £120-£350

What to check first

  1. Locate the mode selector switch on the front panel.
  2. Turn the switch to the 'OFF/RESET' position and wait for 10 seconds.
  3. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to see if the boiler restarts.

Parts commonly replaced

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

Related codes

Full explanation for 09
9x

Your boiler has stopped working because the waste water pipe is backed up or blocked, often due to freezing weather or a buildup of debris.

High DIY-safe £80-140

What to check first

  1. Locate the plastic condensate discharge pipe leading outside your property.
  2. Check if the pipe is frozen and gently pour warm (not boiling) water over it to melt the ice.
  3. Verify if the external end of the pipe is blocked by debris or submerged in water and clear it.
  4. Restart the boiler by turning the mode selector switch to the 'reset' position.

Parts commonly replaced

  • Condensate trap
  • Condensate discharge pipework
  • Float switch

Related codes

Full explanation for 9x
10

Your boiler is experiencing a temporary communication error or sensing issue that is preventing it from firing correctly.

Medium DIY-safe £100-280

What to check first

  1. Locate the mode selector switch on the front control panel.
  2. Turn the switch to the 'OFF/RESET' position and wait for 10 seconds.
  3. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to restart the system.

Parts commonly replaced

  • Main PCB
  • Ignition NTC sensor
  • Wiring harness

Related codes

Full explanation for 10
12

Your boiler is attempting to restart its ignition process because it failed to light or maintain a flame.

High DIY-safe £100-350

What to check first

  1. Check if your gas supply is turned on and other gas appliances are working
  2. Press the reset button or turn the selector switch to 'OFF/RESET' for several seconds
  3. Ensure the condensate pipe (the white plastic pipe outside) isn't frozen if it is winter

Parts commonly replaced

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

Related codes

Full explanation for 12
Showing 21–30 of 86
13

Your boiler has detected an electrical communication problem within its internal wiring which is preventing it from running safely.

High Engineer only £120-280

Parts commonly replaced

  • Wiring harness
  • Main PCB
  • Control board connectors

Related codes

Full explanation for 13
13/14

Your boiler has detected an issue with the internal electrical connections that prevents it from operating safely.

High Engineer only £120-250

Parts commonly replaced

  • Wiring harness
  • PCB (Printed Circuit Board)
  • Sensor connections

Related codes

Full explanation for 13/14
14

Your boiler has detected an internal communication problem between its electronic components and is unable to fire up.

High Engineer only £100-280

Parts commonly replaced

  • Wiring Harness
  • Main Control Board (PCB)

Related codes

Full explanation for 14
15

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 £120-280

Parts commonly replaced

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

Related codes

Full explanation for 15
20

Your boiler has identified a temporary electronic error and is likely trying to restart itself automatically.

Low DIY-safe £80-160

What to check first

  1. Check if the boiler clears the code and restarts automatically after a few minutes
  2. Turn the mode selector switch to the 'OFF/RESET' position, wait five seconds, then turn it back to 'ON'
  3. Ensure your gas supply is active (e.g. check other gas appliances)

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Ignition Electrode

Related codes

Full explanation for 20
20/21/22

Your boiler has detected that it is running much hotter than it should be and has switched itself off to prevent overheating.

High Engineer only £180-350

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Primary Heat Exchanger

Related codes

Full explanation for 20/21/22
21

Your boiler has lost communication with its external controls or is stuck in an internal testing phase, meaning it cannot start the heating cycle.

High DIY-safe £100-280

What to check first

  1. Locate the selector switch on the front panel
  2. Turn the dial to the 'OFF/RESET' position and wait for 10 seconds
  3. Turn the dial back to the 'Hot Water' or 'Heating and Hot Water' position

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Timeclock
  • Wiring Harness

Related codes

Full explanation for 21
23

Your boiler has detected an internal communication problem between its electronic components or a possible electrical connection fault.

High Engineer only £120-350

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)
  • Internal sensors

Related codes

Full explanation for 23
23/31

Your boiler has detected that some of its internal electrical connections or sensors are not communicating correctly, causing the system to stop working to avoid potential damage.

High Engineer only £120-250

Parts commonly replaced

  • Wiring harness
  • PCB (Printed Circuit Board)
  • Air pressure switch sensor

Related codes

Full explanation for 23/31
24

Your boiler has detected an internal communication glitch or a temporary sensor error that it is currently trying to rectify automatically.

Medium DIY-safe £100-250

What to check first

  1. Observe the boiler to see if the code clears automatically
  2. Press the reset button if the fault becomes permanent
  3. Monitor the boiler for frequent recurrences of this code
  4. Contact a qualified engineer if the fault persists after a reset

Parts commonly replaced

  • Main PCB (Control Board)
  • Wiring Loom

Related codes

Full explanation for 24
Showing 31–40 of 86
25

Your boiler has detected a temporary internal communication error or a logic conflict and is likely attempting a self-correction or restart.

Low DIY-safe £0-120

What to check first

  1. Turn the boiler mode selector switch to the 'OFF/RESET' position.
  2. Wait for approximately 10 seconds.
  3. Turn the switch back to either the 'Heating & Hot Water' or 'Hot Water Only' position.

Parts commonly replaced

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

Related codes

Full explanation for 25
26

Your boiler is experiencing a temporary communication error or internal glitch that usually resolves itself, but may require a simple reset if the heating doesn't resume.

Medium DIY-safe £0-120

What to check first

  1. Check if the boiler clears the code automatically after a few minutes
  2. Press the reset button once to clear the temporary fault
  3. Monitor the boiler for recurring instances of this code

Parts commonly replaced

  • No parts usually required
  • Main PCB

Related codes

Full explanation for 26
27

Your boiler has detected an internal electronic communication error or a temporary sensor discrepancy and has paused operation for safety.

Medium DIY-safe £120-280

What to check first

  1. Turn the mode selector knob to the 'OFF/RESET' position.
  2. Wait for 30 seconds.
  3. Turn the knob back to the 'ON' or 'Winter' position to see if the error clears.

Parts commonly replaced

  • Main PCB (Control Board)
  • Thermistor (NTC Sensor)

Related codes

Full explanation for 27
28

Your boiler has detected a temporary internal communication error and is attempting to restart itself.

Medium DIY-safe £0-120

What to check first

  1. Wait up to 15 minutes for the boiler to complete its automatic restart sequence
  2. If the code remains, turn the mode selector switch to the 'OFF/RESET' position
  3. Wait 10 seconds, then return the switch to the 'ON' or 'WINTER' position
  4. Ensure any external controls or thermostats are calling for heat

Parts commonly replaced

  • No parts usually required
  • Main PCB (if fault persists)

Related codes

Full explanation for 28
29

Your boiler has detected an issue with the air pressure or flue gases and is currently waiting for the condition to clear before attempting to restart.

Medium Engineer only £120-280

Parts commonly replaced

  • Air pressure switch
  • Fan
  • Flue venturi
  • Main PCB

Related codes

Full explanation for 29
30

Your boiler has detected a temporary internal communication error or a potential problem with the fan or air supply that may reset itself or require a manual restart.

Medium DIY-safe £120-280

What to check first

  1. Locate the mode selector switch on the front control panel.
  2. Turn the switch to the 'OFF/RESET' position and wait for 10 seconds.
  3. Turn the switch back to the 'ON' position (heating or hot water) to see if the code clears.

Parts commonly replaced

  • Fan
  • Air Pressure Switch
  • Main PCB

Related codes

Full explanation for 30
31

Your boiler is experiencing a communication or configuration error between internal electronic boards that prevents it from starting correctly.

High Engineer only £140-£350

Parts commonly replaced

  • Main PCB
  • Display Interface Board
  • Wiring Harness

Related codes

Full explanation for 31
32

Your boiler has stopped working because the internal fan, which safely exhausts gases out of the flue, is not spinning at the correct speed or has failed completely.

High Engineer only £200-£450

Parts commonly replaced

  • Fan assembly
  • Main circuit board (PCB)
  • Fan wiring harness

Related codes

Full explanation for 32
32/34

Your boiler has stopped working because it cannot properly clear exhaust gases, meaning it is currently unable to safely provide heating or hot water.

High Engineer only £150-300

Parts commonly replaced

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

Related codes

Full explanation for 32/34
33/35

Your boiler's air circulation fan has failed, which means the machine has safely shut down because it cannot vent gasses properly.

High Engineer only £180-350

Parts commonly replaced

  • Fan unit
  • PCB
  • Wiring harness

Related codes

Full explanation for 33/35
Showing 41–50 of 86
34

Your boiler has detected an unusual fan speed or air flow issue but is attempting to reset itself automatically.

Medium Engineer only £120-280

Parts commonly replaced

  • Fan assembly
  • Venture tube
  • Air pressure switch

Related codes

Full explanation for 34
35

Your boiler has stopped working because the internal fan, which safely clears exhaust gases, isn't spinning or communicating correctly with the system.

High Engineer only £180-450

Parts commonly replaced

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

Related codes

Full explanation for 35
36

Your boiler's main internal computer has detected a technical error and has stopped working to protect the system.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Control Board

Related codes

Full explanation for 36
37

Your boiler has detected that the internal fan is spinning too fast, which is preventing the system from starting safely.

High Engineer only £250-450

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 37
38

Your boiler’s internal computer has lost its programmed settings and no longer knows how to operate correctly.

High Engineer only £100-350

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Control Knob set

Related codes

Full explanation for 38
40

Your boiler has detected a temporary internal communication or sensor timing error and is essentially waiting to see if it clears itself.

Medium DIY-safe £80-180

What to check first

  1. Monitor the boiler to see if the code clears automatically
  2. Press the reset button if the code remains or turns into a lockout
  3. Ensure power to the boiler has not been interrupted or fluctuated

Parts commonly replaced

  • Flow thermistor (NTC)
  • Main PCB

Related codes

Full explanation for 40
41

Your boiler has detected a temporary internal communication issue or a potential sensor error and is trying to reset itself.

Low DIY-safe £0-120

What to check first

  1. Turn the control knob to the 'OFF/RESET' position.
  2. Wait for approximately 30 seconds.
  3. Turn the knob back to your desired 'Heating' or 'Hot Water' setting.

Parts commonly replaced

  • Temperature sensor (NTC thermistor)
  • Wiring harness

Related codes

Full explanation for 41
42

Your boiler has detected a temporary internal communication or sensor error that may resolve itself or lead to a full lockout.

Medium DIY-safe £100-220

What to check first

  1. Check if the boiler is in a lockout state
  2. Perform a system reset by turning the selector switch to the reset position and back
  3. Monitor the boiler to see if the code recurs or becomes a permanent fault
  4. Ensure the system pressure is within the normal operating range (usually 1.0 to 1.5 bar)

Parts commonly replaced

  • Temperature thermistor (NTC)
  • Wiring harness
  • Main PCB

Related codes

Full explanation for 42
50

Your boiler's internal computer has encountered a memory or software error that prevents it from running safely.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Control Knob Potentiometers

Related codes

Full explanation for 50
50-59

Your boiler has detected an internal communication glitch or a temporary system error and is attempting to reset itself.

Medium DIY-safe £0-120

What to check first

  1. Observe the boiler to see if it clears the code automatically
  2. Press the reset button or turn the mode selector to 'OFF/RESET' for 5 seconds
  3. If the fault persists or recurs frequently, contact a Gas Safe engineer to inspect the PCB

Parts commonly replaced

  • No parts usually required
  • Main PCB (if fault persists)
Full explanation for 50-59
Showing 51–60 of 86
50/51/52

Your boiler has detected an internal computer error that is causing it to shut down for safety reasons.

High Engineer only £150-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for 50/51/52
51

Your boiler's internal computer has encountered a memory or software error that prevents it from running safely.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Control Knob Potentiometers

Related codes

Full explanation for 51
52

Your boiler's internal computer has encountered a memory or software error that prevents it from running safely.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Control Knob Potentiometers

Related codes

Full explanation for 52
53

Your boiler's electronic control board has detected an internal computer error and has shut down as a safety precaution.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 53
53/54/55/56

Your boiler has detected an internal computer error that is preventing it from operating safely.

High Engineer only £150-350

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Wiring harness

Related codes

Full explanation for 53/54/55/56
54

Your boiler's electronic control board has detected an internal computer error and has shut down as a safety precaution.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 54
56

Your boiler's electronic control board has detected an internal computer error and has shut down as a safety precaution.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 56
60

Your boiler is experiencing a temporary communication error or a sensor timing issue that is causing it to pause current operations.

Medium DIY-safe £100-250

What to check first

  1. Press the reset button on the front control panel
  2. Turn the selector switch to the 'OFF/RESET' position and then back to 'ON'
  3. Monitor the boiler to see if the error code clears and operation resumes

Parts commonly replaced

  • Thermistor (NTC Sensor)
  • Main Control Board

Related codes

Full explanation for 60
60/61

Your boiler has stopped working because it is unable to accurately read the temperature of the water inside the system.

High Engineer only £120-200

Parts commonly replaced

  • NTC Thermistor
  • Wiring harness

Related codes

Full explanation for 60/61
61

Your boiler's internal temperature sensors are struggling to read the water temperature correctly, preventing the system from heating up properly.

High Engineer only £90-160

Parts commonly replaced

  • NTC Thermistor
  • Flow Sensor
  • Return Sensor

Related codes

Full explanation for 61
Showing 61–70 of 86
62

Your boiler has detected an internal electrical communication error or a wiring issue, which is preventing it from running safely.

High Engineer only £120-350

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 62
70

Your boiler has detected a temporary technical issue that frequently relates to an internal communication error or a sensor detecting an unusual reading.

High DIY-safe £100-280

What to check first

  1. Locate the mode selector switch on the front panel
  2. Turn the switch to the 'OFF/RESET' position
  3. Wait for 30 seconds
  4. Move the switch back to the 'ON' (winter or summer) position

Parts commonly replaced

  • Main PCB (Control Board)
  • Thermistor

Related codes

Full explanation for 70
70/72/74

Your boiler is struggling to circulate water, likely because the internal valves are shut or the internal pump has seized up.

High Engineer only £120-250

Parts commonly replaced

  • Circulation pump
  • Flow sensor
  • Diverter valve

Related codes

Full explanation for 70/72/74
71

Your boiler has detected an internal communication or temperature sensor error that is currently preventing it from running normally.

High DIY-safe £120-280

What to check first

  1. Turn the mode selector switch to the 'OFF/RESET' position.
  2. Wait for approximately 30 seconds.
  3. Turn the switch back to the 'ON' or heating/hot water position.

Parts commonly replaced

  • NTC Temperature Sensor
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 71
71/73

Your boiler is struggling to accurately detect or manage the temperature of the water flowing through the system.

High Engineer only £150-250

Parts commonly replaced

  • NTC temperature sensor
  • PCB control board

Related codes

Full explanation for 71/73
72

Your boiler has detected a temporary sensor problem or an unusual temperature difference, which may cause the system to pause or restart.

Medium DIY-safe £80-160

What to check first

  1. Check if the boiler display resets itself automatically after a short period
  2. Press the reset button or turn the mode selector switch to 'OFF/RESET' and then back to heating/hot water
  3. Ensure your system pressure is topped up to between 1 and 1.5 bar on the pressure gauge

Parts commonly replaced

  • NTC Temperature Sensor
  • Primary Heat Exchanger (cleaning)

Related codes

Full explanation for 72
73

Your boiler has detected an unusual temperature reading or a possible blockage that is preventing water from circulating correctly.

High Engineer only £120-280

Parts commonly replaced

  • Flow NTC sensor
  • Return NTC sensor
  • Circulation pump

Related codes

Full explanation for 73
74

Your boiler is unable to move water around the system because either the main pump is stuck or the internal valves are blocked.

High Engineer only £180-350

Parts commonly replaced

  • Circulation pump
  • Diverter valve
  • Flow switch

Related codes

Full explanation for 74
75

Your boiler has detected an internal electrical communication error or a wiring issue that is preventing it from working safely.

High Engineer only £100-£350

Parts commonly replaced

  • Wiring harness
  • Main PCB
  • Ignition transformer

Related codes

Full explanation for 75
75/76

Your boiler is having difficulty communicating with its internal controls due to a connection issue within its wiring, which means it has safely shut down to prevent incorrect operation.

High Engineer only £120-220

Parts commonly replaced

  • Wiring harness
  • PCB (Printed Circuit Board)
  • Sensor wiring loom
Full explanation for 75/76
Showing 71–80 of 86
76

Your boiler has detected an internal electrical communication error or a wiring issue that is preventing it from working safely.

High Engineer only £100-£350

Parts commonly replaced

  • Wiring harness
  • Main PCB
  • Ignition transformer

Related codes

Full explanation for 76
78

Your boiler has detected a temporary internal communication error or a sensor synchronization issue that is preventing it from running properly.

High DIY-safe £100-280

What to check first

  1. Turn the selector switch to the 'OFF/RESET' position.
  2. Wait for approximately 30 seconds.
  3. Turn the selector switch back to the 'ON' position (Heating and Hot Water icon).

Parts commonly replaced

  • Domestic Hot Water (DHW) Thermistor
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 78
79

Your boiler has detected an internal communication error or a temporary processing fault that is preventing it from running properly.

High DIY-safe £150-350

What to check first

  1. Locate the mode selector switch on the front panel
  2. Turn the switch to the 'OFF/RESET' position and wait for 10 seconds
  3. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to see if the error clears

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 79
80

Your boiler is experiencing a temporary communication error or initialization issue that may prevent it from starting correctly.

Medium DIY-safe £100-220

What to check first

  1. Locate the mode selector switch on the front of the boiler.
  2. Turn the switch to the 'OFF/RESET' position and wait for 5 seconds.
  3. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to restart the system.

Parts commonly replaced

  • Main Control PCB
  • Wiring harness

Related codes

Full explanation for 80
80-83

Your boiler has detected a problem with its internal brain or main control panel, preventing it from functioning correctly.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Loom

Related codes

Full explanation for 80-83
80/90/91

Your boiler has detected an internal electronic error that is preventing it from operating correctly.

High Engineer only £150-300

Parts commonly replaced

  • PCB (Printed Circuit Board)
  • Wiring harness

Related codes

Full explanation for 80/90/91
81

Your boiler has identified an internal sensor or communication error that is preventing it from running properly.

High Engineer only £120-250

Parts commonly replaced

  • Main PCB
  • NTC thermistor

Related codes

Full explanation for 81
82

Your boiler has detected an unstable flame or a temporary communication issue and is trying to reset itself automatically.

Medium DIY-safe £100-280

What to check first

  1. Wait up to 15 minutes to see if the boiler clears the code and restarts automatically
  2. Perform a manual reset by turning the mode selector switch to the 'R' position for a few seconds
  3. Check that other gas appliances in your home are working to ensure there is a gas supply

Parts commonly replaced

  • Ignition electrode
  • Flame sensing electrode
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 82
83

Your boiler is experiencing a communication error between its internal parts, which it is currently trying to resolve automatically.

Low DIY-safe £100-£250

What to check first

  1. Wait up to 15 minutes for the boiler to self-correct
  2. Turn the selector switch to the 'Reset' position, wait for two seconds, and turn it back to the 'On' position
  3. Check if the boiler pressure is between 1 and 1.5 bar on the gauge

Parts commonly replaced

  • Main Control PCB
  • Wiring Loom

Related codes

Full explanation for 83
90

Your boiler has paused operation due to a temporary internal communication or sensor error that may clear itself or indicate a service is needed.

Low DIY-safe £0-120

What to check first

  1. Turn the selector switch to the 'OFF/RESET' position.
  2. Wait approximately 30 seconds.
  3. Turn the selector switch back to either the 'Heating' or 'Hot Water' position.

Parts commonly replaced

  • NTC Temperature Sensor
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 90
Showing 81–86 of 86
91

Your boiler has detected a temporary service issue that is preventing it from completing its ignition sequence, though it may resolve itself or require a simple reset.

Medium DIY-safe £80-160

What to check first

  1. Locate the mode selector switch on the front panel
  2. Turn the dial to the 'OFF/RESET' position and wait for 5 seconds
  3. Turn the dial back to the original winter or summer position to see if the error clears

Parts commonly replaced

  • Ignition module
  • Flame sensing electrode

Related codes

Full explanation for 91
92

Your boiler has detected a temporary internal error and is attempting to self-correct or reset after a specific cycle.

Medium DIY-safe £0-80

What to check first

  1. Wait for the boiler to complete its internal self-test cycle
  2. Press the reset button if the code remains after 10 minutes
  3. Monitor the boiler for recurring faults
  4. Ensure power to the boiler is stable and not switched off prematurely

Parts commonly replaced

  • None (Software reset)
  • Main PCB (if code persists)

Related codes

Full explanation for 92
93

Your boiler is experiencing a temporary communication or sensor error that may resolve itself but often indicates a part is beginning to fail.

Medium DIY-safe £100-280

What to check first

  1. Press the reset button to clear the temporary error
  2. Monitor the boiler for recurring faults
  3. Ensure power supply to the boiler is stable
  4. Contact a Gas Safe engineer if the code persists

Parts commonly replaced

  • Main PCB
  • NTC Sensor
  • Wiring loom

Related codes

Full explanation for 93
93/95

Your boiler is unable to drain away water produced during normal operation because the waste pipe is obstructed, causing the system to stop working to prevent internal damage.

High DIY-safe £80-150

What to check first

  1. Locate the plastic pipe exiting the bottom of the boiler that leads to a drain or soakaway.
  2. Inspect the external end of the pipe for blockages, such as leaves, debris, or ice if it is winter.
  3. Ensure the pipe is not bent or kinked and flows freely into your household drainage system.

Parts commonly replaced

  • Condensate trap
  • Condensate pipework assembly
Full explanation for 93/95
94

Your boiler has detected a minor internal communication error and and is currently attempting to automatically reset itself.

Low DIY-safe £0-120

What to check first

  1. Wait up to 10 minutes to see if the boiler clears the code automatically
  2. Turn the mode selector switch to the 'OFF/RESET' position and then back to 'ON'
  3. Check if the display returns to the standard temperature output

Parts commonly replaced

  • None (Software reset)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 94
95

Your boiler has detected a temporary internal communication or processing error and is attempting to resolve itself.

Low DIY-safe £0-120

What to check first

  1. Wait for the boiler to complete its current operation and reset the code automatically
  2. Turn the mode selector knob to the 'OFF/RESET' position and then back to 'ON'
  3. Ensure there is a constant power supply to the unit without frequent switching

Parts commonly replaced

  • None (Software reset)
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 95