Heatline Solaris Fault codes & diagnostics

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

Combi Natural Gas 24-30 kW 2006-2010 Discontinued

Replaced by: Capriz

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.
1 Emergency 64 High 6 Medium 26 Low
Just want the most common Heatline Solaris faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 97 documented codes

Tap any card for details

0.8bar

Your boiler has detected that the water pressure is too low for it to operate safely and effectively.

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/valves 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 0.8bar
E01

Your boiler has failed to light the gas or cannot confirm a flame is present, meaning it cannot provide heat or hot water.

High DIY-safe £120-350

What to check first

  1. Check if your gas supply is active by testing another gas appliance like a hob.
  2. Verify that your credit meter has sufficient funds.
  3. Press the Reset button on the boiler control panel for 3 seconds.

Parts commonly replaced

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

Related codes

Full explanation for E01
E02

Your boiler has stopped working because it cannot confirm that the fan is safely clearing waste gases from the system.

High Engineer only £120-£250

Parts commonly replaced

  • Air pressure switch
  • Fan assembly
  • Venture tube
  • APS silicone tubing

Related codes

Full explanation for E02
E03

Your boiler has detected that it 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. 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 pressure gauge.
  3. Press the reset button on the control panel to see if the fault clears after the system has cooled down.

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Main Heat Exchanger (if blocked)

Related codes

Full explanation for E03
E05

Your boiler has detected an issue with the sensor that monitors the temperature of the water flowing to your radiators, which means it cannot safely heat your home.

High Engineer only £90-160

Parts commonly replaced

  • Central heating flow NTC sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for E05
E06

Your boiler is struggling to provide hot water correctly because its dedicated temperature sensor has developed a technical fault or stopped working.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW Temperature Sensor (NTC thermistor)
  • Sensor wiring harness

Related codes

Full explanation for E06
E09

Your boiler has detected that the water pressure is too low, causing the system to shut down for safety.

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 one or two taps on the loop until you hear water entering the system.
  3. Watch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure sensor
Full explanation for E09
E12

Your boiler's internal computer brain has suffered a software memory failure and can no longer process instructions.

High Engineer only £280-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • EEPROM Chip
Full explanation for E12
E15

Your boiler has detected an unusual temperature difference between the water leaving the unit and the water returning to it, often caused by a circulation blockage or a sensor failure.

High Engineer only £120-£350

Parts commonly replaced

  • Flow NTC sensor
  • Return NTC sensor
  • Circulation pump
  • Main PCB

Related codes

Full explanation for E15
E16

Your boiler has stopped working because one of its internal temperature sensors is providing an incorrect reading or has failed completely.

High Engineer only £90-160

Parts commonly replaced

  • Return NTC Thermistor
  • Sensor wiring harness

Related codes

Full explanation for E16
Showing 11–20 of 97
E22

Your boiler's internal computer has lost its settings or is having trouble communicating with the main control board, preventing the system from starting.

High Engineer only £220-450

Parts commonly replaced

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

Related codes

Full explanation for E22
E77

Your boiler has detected an electrical problem with the parts that control the gas flow, causing it to shut down for safety.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Main PCB (Printed Circuit Board)
  • Wiring harness
Full explanation for E77
Err

Your boiler's electronic display panel is failing to communicate with the internal system, which means the boiler cannot operate or respond to your commands.

High Engineer only £150-300

Parts commonly replaced

  • User interface/Display PCB
  • Wiring harness

Related codes

Full explanation for Err
F00

Your boiler has lost the ability to measure the temperature of the water being sent to your radiators, so it has shut down as a precaution to prevent overheating.

High Engineer only £120-220

Parts commonly replaced

  • NTC flow temperature sensor

Related codes

Full explanation for F00
F0

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

High DIY-safe £0-120

What to check first

  1. Locate the flexible filling loop underneath the boiler.
  2. Slowly open the small valves on the loop until you hear water entering the system.
  3. Watch the pressure gauge and close the valves once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for F0
F01

Your boiler is failing to light because it cannot detect a flame or is not receiving a steady gas supply.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
Full explanation for F01
F1

Your boiler has failed to light the gas, which means your heating and hot water will not work until the system is reset or repaired.

High DIY-safe £100-£350

What to check first

  1. Check that your gas pre-payment meter (if you have one) has credit.
  2. Ensure your external gas emergency control valve is in the 'on' position.
  3. Press and hold the reset button for 5 seconds to attempt a restart.

Parts commonly replaced

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

Related codes

Full explanation for F1
F2

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

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure your boiler pressure is between 1 and 1.5 bar on the gauge.
  3. Once the boiler has cooled down, try pressing the reset button.

Parts commonly replaced

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

Related codes

Full explanation for F2
F3

Your boiler is unable to move water around the system correctly, which is causing it to overheat and shut down for safety.

High Engineer only £180-450

Parts commonly replaced

  • Circulation pump
  • Main heat exchanger
  • Diverter valve

Related codes

Full explanation for F3
F4

Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot provide hot water to your taps.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW Thermistor (NTC Sensor)
  • Connecting wiring harness

Related codes

Full explanation for F4
Showing 21–30 of 97
F5

Your boiler has detected an issue with the sensor that monitors the temperature of the water used to heat your radiators.

High Engineer only £90-160

Parts commonly replaced

  • Central Heating (CH) NTC sensor
  • Wiring harness

Related codes

Full explanation for F5
F6

Your boiler is having trouble communicating with the outside temperature sensor, which helps it run efficiently based on the weather.

Low DIY-safe £70-130

What to check first

  1. Locate the external sensor on an outside wall to check for obvious physical damage or loose wires
  2. Turn the boiler power off and back on to see if the fault clears
  3. If the issue persists, the boiler will still provide heat but will revert to standard internal settings

Parts commonly replaced

  • External temperature sensor (Outdoor weather compensator)
  • Wiring harness

Related codes

Full explanation for F6
F7

Your boiler has detected an electrical supply issue where the power coming into the system is too low for it to run safely.

High Engineer only £150-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Power Supply Components

Related codes

Full explanation for F7
F8

Your boiler has detected that the fan, which safely removes waste gases from your home, is not spinning at the correct speed or has stopped working entirely.

High Engineer only £180-£350

Parts commonly replaced

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

Related codes

Full explanation for F8
F9

Your boiler's internal computer is having trouble communicating with the other parts of the system, meaning it cannot process commands to provide heating or hot water.

High Engineer only £220-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for F9
F10

Your boiler is struggling to circulate water properly, which stops your heating and hot water from working correctly.

High Engineer only £150-300

Parts commonly replaced

  • Central heating pump
  • System filter
  • Isolation valve

Related codes

Full explanation for F10
F11

Your boiler has lost the ability to measure the temperature of the water returning to it, so it has shut down to prevent potential overheating.

High Engineer only £120-180

Parts commonly replaced

  • Return NTC sensor
  • Wiring harness

Related codes

Full explanation for F11
F20

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

High Engineer only £120-250

Parts commonly replaced

  • NTC thermistor sensor
  • Pump
  • Primary heat exchanger

Related codes

Full explanation for F20
F22

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

High DIY-safe £80-150

What to check first

  1. Locate the filling loop (a silver flexible hose) underneath the boiler.
  2. Open the small valve or tap on the loop to allow mains water into the boiler.
  3. Monitor the pressure gauge on the front until it reaches 1.5 bar, then turn the valve firmly off.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure sensor

Related codes

Full explanation for F22
F23

Your boiler has detected that the water is not circulating properly, meaning it is getting hot in one area but not moving to the rest of your system fast enough.

High Engineer only £150-300

Parts commonly replaced

  • Central heating pump
  • Flow and return thermistors
  • System filter blockage

Related codes

Full explanation for F23
Showing 31–40 of 97
F24

Your boiler is struggling to move water around the system fast enough, likely due to low water pressure or a blockage.

High DIY-safe £120-250

What to check first

  1. Check your boiler pressure gauge; if it is below 1 bar, use the filling loop to top it up to 1.5 bar
  2. Ensure all radiator valves are fully open
  3. Turn the boiler off and back on again to reset the temporary fault

Parts commonly replaced

  • Central heating pump
  • System filter
  • Pressure sensor

Related codes

Full explanation for F24
F26

Your boiler has detected a problem with the internal part that controls the flow of gas, meaning it cannot safely start up to provide heat or hot water.

High Engineer only £180-300

Parts commonly replaced

  • Gas valve stepper motor
  • Gas valve assembly

Related codes

Full explanation for F26
F27

Your boiler is failing to detect a flame, so it has purposefully shut down to prevent gas from building up inside the system.

High Engineer only £120-250

Parts commonly replaced

  • Flame rectification probe
  • Ignition lead
  • Printed Circuit Board (PCB)

Related codes

Full explanation for F27
F28

Your boiler is trying to start but the flame is not catching, meaning it cannot provide you with heating or hot water.

High Engineer only £120-250

Parts commonly replaced

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

Related codes

Full explanation for F28
F29

Your boiler has stopped because the internal flame keeps going out while it is trying to heat your water or home.

High Engineer only £120-250

Parts commonly replaced

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

Related codes

Full explanation for F29
F32

Your boiler is struggling to push air through its system properly, which has caused it to stop working to keep you safe.

High Engineer only £150-250

Parts commonly replaced

  • Air pressure switch
  • Flue fan
  • Venturi tube
Full explanation for F32
F49

Your boiler has lost the communication signal between the main controller and the heating system, meaning it cannot receive instructions to provide heat or hot water.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
  • External thermostat/programmer

Related codes

Full explanation for F49
F61

Your boiler's electronic control centre has detected a critical internal error and has shut down to prevent damage or unsafe operation.

High Engineer only £250-450

Parts commonly replaced

  • Printed circuit board (PCB)

Related codes

Full explanation for F61
F62

Your boiler has detected an issue with its internal gas supply system and has safely shut itself down to prevent any unsafe operation.

Emergency Engineer only £180-300

Parts commonly replaced

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

Related codes

Full explanation for F62
F63

Your boiler's internal computer has encountered a critical memory error and can no longer safely control the heating system, requiring professional attention.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)

Related codes

Full explanation for F63
Showing 41–50 of 97
F64

Your boiler is struggling to accurately read the water temperature, causing it to shut down for safety because the readings are changing too quickly.

High Engineer only £120-220

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness lead
  • Printed Circuit Board (PCB)

Related codes

Full explanation for F64
F65

Your boiler has detected that its internal computer has become dangerously hot and has shut itself down to prevent fire or electrical damage.

High Engineer only £200-400

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal ventilation cooling fan

Related codes

Full explanation for F65
F67

Your boiler has detected an issue with the flame detection system, meaning it cannot confirm that the burner is safely lit and will refuse to operate as a precaution.

High Engineer only £150-300

Parts commonly replaced

  • Main circuit board (PCB)
  • Flame rectification electrode
  • Wiring harness

Related codes

Full explanation for F67
F68

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

High Engineer only £150-300

Parts commonly replaced

  • Flame rectification electrode
  • Ignition lead
  • PCB

Related codes

Full explanation for F68
F70

Your boiler's electronic control panel is not communicating correctly with the main internal computer, which prevents the system from starting up safely.

High Engineer only £150-300

Parts commonly replaced

  • User Interface PCB
  • Main Control Board

Related codes

Full explanation for F70
F71

Your boiler has lost the ability to accurately measure the temperature of the water used for your radiators, causing it to shut down for safety reasons.

High Engineer only £120-200

Parts commonly replaced

  • NTC flow temperature sensor
  • Wiring harness

Related codes

Full explanation for F71
F72

Your boiler has detected an unusual temperature gap between the outgoing and incoming water, indicating the system is struggling to circulate heat correctly.

High Engineer only £150-250

Parts commonly replaced

  • NTC Temperature Sensors
  • Central Heating Pump
  • Plate Heat Exchanger

Related codes

Full explanation for F72
F73

Your boiler is struggling to accurately measure the water pressure inside the system, which is preventing it from safely starting up your heating.

High Engineer only £120-220

Parts commonly replaced

  • Pressure sensor
  • Wiring harness

Related codes

Full explanation for F73
F74

Your boiler's sensor is struggling to read your heating system's pressure, which prevents the unit from starting the heating or hot water safely.

High Engineer only £150-250

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness

Related codes

Full explanation for F74
F76

Your boiler has detected an internal issue with a safety device designed to shut the system down if it gets too hot, and it will no longer operate until this is inspected.

High Engineer only £120-220

Parts commonly replaced

  • Thermal fuse link
  • Overheat thermostat
  • Wiring harness
Full explanation for F76
Showing 51–60 of 97
F77

Your boiler has detected an issue with the internal component that controls the gas supply, meaning it cannot safely ignite to provide heating or hot water.

High Engineer only £150-300

Parts commonly replaced

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

Related codes

Full explanation for F77
F83

Your boiler has detected that there is not enough water pressure inside the system for it to heat your home safely.

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is usually a silver braided hose under the boiler.
  2. Open the valves attached to the loop slowly to allow water into the system.
  3. Monitor the pressure gauge on the front of the boiler until the needle reaches between 1.0 and 1.5 bar, then turn the valves off securely.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor

Related codes

Full explanation for F83
F84

Your boiler is confused because its temperature sensors are giving conflicting readings or are not properly connected, causing it to stop heating your home to prevent potential damage.

High Engineer only £120-200

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness

Related codes

Full explanation for F84
F85

Your boiler's temperature sensors are reporting conflicting information because they are detecting heat from the same spot, causing the system to stop heating for safety.

High Engineer only £120-220

Parts commonly replaced

  • NTC temperature sensors
  • Wiring harness

Related codes

Full explanation for F85
F86

Your boiler has lost the signal from the sensor that monitors your underfloor heating system, preventing it from activating those circuits.

Medium Engineer only £120-200

Parts commonly replaced

  • Underfloor heating sensor
  • Wiring harness
  • PCB
Full explanation for F86
OC

Your boiler has detected an outdoor temperature sensor and is adjusting its settings to match the weather outside.

Low DIY-safe £0

What to check first

  1. Check that the outdoor sensor is not covered or damaged
  2. Monitor the boiler to ensure it continues providing heating and hot water as normal
  3. Consult your manual if you wish to adjust the outdoor weather compensation settings
Full explanation for OC
S.00

Your boiler is currently in standby mode because it has not received a signal from your thermostat to turn on the heating.

Low DIY-safe

What to check first

  1. Check that your room thermostat is switched on and set to a temperature higher than the current room temperature.
  2. Ensure your external timer or programmer is set to 'on' or 'timed' mode.
  3. Check that your boiler's internal heating dial is turned up.

Related codes

Full explanation for S.00
S.01

Your boiler is currently performing a required safety check by running its internal fan before attempting to light the flame.

Low Engineer only

Parts commonly replaced

  • Fan
  • Air pressure switch
  • Printed circuit board

Related codes

Full explanation for S.01
S.03

Your boiler is failing to light the flame needed to produce heat or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Ignition lead
Full explanation for S.03
Showing 61–70 of 97
S.05

Your boiler is currently cooling down by running its internal components to clear heat, which is a normal part of the shutdown process.

Low Engineer only

Related codes

Full explanation for S.05
S.06

Your boiler is currently running its internal fan to safely vent any remaining gases after the burner has turned off, which is a normal part of the shutdown process.

Low Engineer only

Related codes

Full explanation for S.06
S.07

Your boiler is simply performing a routine safety cycle where the pump continues to run for a short time after heating to distribute residual warmth.

Low Engineer only

Related codes

Full explanation for S.07
S.08

Your boiler is currently taking a temporary rest pause between heating cycles to prevent excessive wear and tear, which is a normal part of its operation.

Low Engineer only

Related codes

Full explanation for S.08
S.11

Your boiler is currently preparing to ignite, but the internal fan is checking its position before the system starts burning fuel.

Low DIY-safe

What to check first

  1. Observe the boiler for 1-2 minutes as this is often a normal operational status message.
  2. If the code persists without the boiler firing, try pressing the reset button.
  3. If the boiler remains stuck on this code after a reset, contact a Gas Safe engineer to inspect the fan and air pressure switch.

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Main PCB
Full explanation for S.11
S.13

Your boiler is failing to light the flame, so it has safely stopped operating to prevent gas from building up inside.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board
Full explanation for S.13
Showing 71–80 of 97
S.16

Your boiler is simply performing a routine safety process where the fan runs for a short time after the heating switches off to clear any leftover gases safely.

Low Engineer only

Parts commonly replaced

  • Fan unit
  • PCB

Related codes

Full explanation for S.16
S.20

Your boiler is currently preparing to fire by checking the water circulation, which is a normal part of the start-up process.

Low Engineer only

Parts commonly replaced

  • Central heating pump
  • PCB

Related codes

Full explanation for S.20
S.21

Your boiler is currently checking that its internal air extraction system is working correctly before it attempts to ignite the flame.

Low DIY-safe £120-250

What to check first

  1. No action required; this is a normal operational status message
  2. Monitor the display to ensure it proceeds to the next stage of ignition
  3. If the code stays on the screen for a long period, try a simple reset

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board
Full explanation for S.21
S.23

Your boiler is failing to light the flame properly, meaning it cannot provide you with heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Ignition lead
  • Printed Circuit Board (PCB)
  • Gas valve
Full explanation for S.23
S.25

Your boiler is currently cooling down its internal components after finishing a heating or hot water cycle, which is a normal part of the shutdown process.

Low Engineer only

Related codes

Full explanation for S.25
S.28

Your boiler has temporarily stopped heating your hot water cylinder because it has reached a protective safety limit meant to prevent the system from overheating.

Medium Engineer only £120-250

Parts commonly replaced

  • NTC temperature sensor
  • DHW pump
  • Diverter valve

Related codes

Full explanation for S.28
Showing 81–90 of 97
S.30

Your boiler is currently in standby mode because it hasn't received a signal from your thermostat or hot water tap to start heating.

Low DIY-safe

What to check first

  1. Turn up your room thermostat to a temperature higher than the current room temperature
  2. Check if your timer or programmer is set to 'On' or 'Timed' rather than 'Off'
  3. Run a hot water tap to see if the boiler initiates a firing sequence

Related codes

Full explanation for S.30
S.31

Your boiler is currently set to only provide hot water and is ignoring requests for central heating.

Low DIY-safe

What to check first

  1. Check your external timer or programmer to see if it is currently set to 'Hot Water Only' or 'Summer Mode'.
  2. Ensure your room thermostat or smart controller is set to a temperature higher than the current room temperature.
  3. Adjust the boiler's internal winter/summer settings via the control panel to enable heating mode.
Full explanation for S.31
S.32

Your boiler is struggling to operate its internal fan correctly, which is preventing it from safely lighting and heating your home.

High Engineer only £150-£300

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Venturi/Air pressure tube

Related codes

Full explanation for S.32
S.35

Your boiler is having trouble managing the airflow needed to operate safely and has shut down to prevent any issues.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Venturi

Related codes

Full explanation for S.35
S.36

Your boiler has detected that water is not circulating properly through the heating system, which is preventing it from distributing warmth to your radiators.

High Engineer only £150-300

Parts commonly replaced

  • Central heating pump
  • Diverter valve
  • System filter
  • Heat exchanger
Full explanation for S.36
S.37

Your boiler has detected that the internal fan responsible for safely venting fumes is not spinning at the correct speed to run efficiently.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)

Related codes

Full explanation for S.37
S.41

Your boiler's internal water pressure is currently too high, which prevents it from operating safely to protect the system.

High DIY-safe £80-150

What to check first

  1. Locate a radiator in your home with a bleed valve
  2. Place a cloth and container under the valve
  3. Open the bleed valve slowly to release water until the boiler pressure gauge drops to the green zone (usually 1.5 bar)
  4. Close the valve tightly

Parts commonly replaced

  • Pressure relief valve
  • System pressure sensor
Full explanation for S.41
S.53

Your boiler has paused its heating process because the water circulating through your radiators is not returning to the unit quickly enough, often due to a blockage or restricted flow.

Medium DIY-safe £100-250

What to check first

  1. Check that your radiator valves are fully open throughout the house
  2. Ensure your thermostat is set correctly
  3. Bleed your radiators to remove any trapped air that may be causing a blockage

Parts commonly replaced

  • Central heating pump
  • System filter
  • Diverter valve

Related codes

Full explanation for S.53
S.54

Your boiler has temporarily stopped heating because the water is not flowing through the system correctly, likely due to low water pressure or an airlock.

High DIY-safe £90-180

What to check first

  1. Check your boiler pressure gauge to see if it is below 1 bar.
  2. If low, use the external filling loop or internal key to top up the boiler pressure to 1.5 bar.
  3. Bleed your radiators to release any trapped air and then re-check the pressure.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Heating pump
Full explanation for S.54
Showing 91–97 of 97
S.58

Your boiler is temporarily running at a restricted, pre-set power level to protect itself, rather than adjusting its heat output normally.

Medium Engineer only £120-250

Parts commonly replaced

  • NTC sensor
  • Main printed circuit board
  • Gas valve
Full explanation for S.58
S.92

Your boiler has detected that water is not flowing through the system correctly, which is preventing it from heating your home or your water.

High Engineer only £150-250

Parts commonly replaced

  • DHW flow sensor
  • Diverter valve
  • Central heating pump
Full explanation for S.92
S.95

Your boiler has detected an electrical power problem that is preventing it from safely heating your home or water.

High Engineer only £150-300

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Wiring harness
Full explanation for S.95
S.96

Your boiler has detected that hot water cannot circulate properly through the system, so it has safely shut down to prevent overheating.

High Engineer only £120-250

Parts commonly replaced

  • Return temperature sensor
  • Central heating pump
  • System filter
Full explanation for S.96
S.97

Your boiler has detected that the water pressure sensor is not providing a signal, which prevents the heating and hot water from turning on.

High Engineer only £150-250

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness
Full explanation for S.97
S.98

Your boiler has detected that hot water cannot flow through the pipes properly, which has caused it to stop working for your radiators and taps.

High Engineer only £150-300

Parts commonly replaced

  • NTC Sensor
  • Primary Heat Exchanger
  • Central Heating Pump
Full explanation for S.98