Ravenheat TS 100 Fault codes & diagnostics

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

Combi Natural Gas 29 kW Discontinued

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46 High 3 Medium
Just want the most common Ravenheat TS 100 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 49 documented codes

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01

Your boiler has failed to light a flame and has locked itself out for safety.

High DIY-safe £120-£350

What to check first

  1. Check if your gas supply is active (e.g. check other gas appliances or credit on your meter)
  2. Press the Reset button on the front of the control panel
  3. Ensure the condensate pipe (outside white pipe) isn't frozen if it is currently sub-zero temperatures

Parts commonly replaced

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

Related codes

Full explanation for 01
02

Your boiler has likely overheated or a sensor has detected a temperature issue, causing it to shut down for safety.

High DIY-safe £100-220

What to check first

  1. Locate the reset button on the control panel
  2. Press and hold the reset button for several seconds
  3. Ensure your radiator valves are open and that the system pressure is between 1 and 1.5 bar

Parts commonly replaced

  • Overheat Thermostat
  • NTC Temperature Sensor
  • Circulation Pump

Related codes

Full explanation for 02
02E

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

High DIY-safe £180-350

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the pressure gauge
  2. Ensure all radiator valves are fully open
  3. Try bleeding your radiators to remove any trapped air

Parts commonly replaced

  • Circulation pump
  • Pump capacitor
  • Auto air vent

Related codes

Full explanation for 02E
03E

Your boiler is struggling to detect if water is moving through the system, which means it cannot heat your water or radiators reliably.

High Engineer only £120-190

Parts commonly replaced

  • Flow thermistor
  • Flow sensor wiring harness
  • Main heat exchanger sensor

Related codes

Full explanation for 03E
04

Your boiler has switched itself off because it has become too hot to operate safely.

High Engineer only £120-£250

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Limit Stat

Related codes

Full explanation for 04
04E

Your boiler is struggling to accurately measure the temperature of your water, which usually means your hot taps will only run cold.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW Temperature Sensor (NTC Thermistor)
  • Wiring harness connecting the sensor

Related codes

Full explanation for 04E
05E

Your boiler has stopped working because the internal fan is not spinning or communicating properly, which means it cannot safely vent exhaust gases.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 05E
06E

Your boiler has detected that the temperature near the heating sensor is too high, causing the system to shut down for protection.

High Engineer only £90-180

Parts commonly replaced

  • Central heating NTC temperature sensor
  • Circulation pump
  • Main heat exchanger

Related codes

Full explanation for 06E
08E

Your boiler has detected that the water pressure is too low to operate safely, which is usually caused by a leak or air being bled from your radiators.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (a silver flexible hose) underneath or near the boiler
  2. Slowly open both small valves on the filling loop to allow water into the system
  3. Watch the pressure gauge and close both valves firmly once it reaches between 1.0 and 1.5 bar

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure sensor
Full explanation for 08E
09E

Your boiler has shut down because it has reached an unsafe temperature, triggered by an internal sensor that detects overheating.

High Engineer only £100-£280

Parts commonly replaced

  • Overheat Thermostat
  • Main Heat Exchanger
  • Circulating Pump

Related codes

Full explanation for 09E
Showing 11–20 of 49
10E

Your boiler has too much water inside the system, which causes it to shut down for safety.

High DIY-safe £80-160

What to check first

  1. Check that the filling loop valves are fully closed
  2. Bleed a radiator to release excess water pressure
  3. Monitor the pressure gauge until it returns to between 1 and 1.5 bar
  4. Restart the boiler

Parts commonly replaced

  • Filling loop valve
  • Expansion vessel
  • Pressure relief valve
Full explanation for 10E
12

Your boiler has stopped providing heating and hot water because it can no longer accurately measure the temperature of the water inside the unit.

High Engineer only £90-160

Parts commonly replaced

  • NTC Heating Sensor
  • Sensor Wiring Harness
Full explanation for 12
13E

Your boiler's computer brain has encountered a software glitch and is unable to run its normal operations.

High DIY-safe £180-350

What to check first

  1. Locate the reset button or dial on the front control panel
  2. Press and hold the reset button for 5 seconds, then release
  3. Wait up to 3 minutes for the boiler to complete its reboot sequence

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 13E
17

Your boiler has stopped working because the fan that helps remove waste gases is not receiving the correct amount of electrical power.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Wiring harness
Full explanation for 17
21E

Your boiler has detected that the water coming back from your radiators is too hot, causing the system to shut down to prevent damage.

High DIY-safe £120-250

What to check first

  1. Check that at least two or three radiator valves are fully open
  2. Ensure the central heating bypass valve is not closed
  3. Check that the boiler pressure is between 1 and 1.5 bar

Parts commonly replaced

  • Central heating return NTC sensor
  • Circulation pump
  • Main heat exchanger (flushing)

Related codes

Full explanation for 21E
22E

Your boiler has shut down because the exhaust fumes are becoming too hot, which is a safety mechanism to prevent damage to the appliance.

High Engineer only £120-£350

Parts commonly replaced

  • Flue Thermistor
  • Heat Exchanger
  • Main PCB

Related codes

Full explanation for 22E
23E

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

High Engineer only £120-190

Parts commonly replaced

  • Flue gas sensor (NTC)
  • Sensor wiring harness

Related codes

Full explanation for 23E
24E

Your boiler has detected a problem with the sensor that monitors water temperature returning from your radiators, meaning it cannot operate safely or efficiently.

High Engineer only £90-160

Parts commonly replaced

  • Central heating return NTC sensor
  • Wiring harness
  • Main control board

Related codes

Full explanation for 24E
25E

Your boiler's internal components have likely frozen due to extremely cold weather, preventing it from heating your home or water safely.

High DIY-safe £80-160

What to check first

  1. Turn the boiler off at the electrical isolation switch.
  2. Place hot (but not boiling) water bottles or heat pads against the heat exchanger and internal pipes to gently thaw them.
  3. Check if your external condensate pipe is frozen and thaw it using warm water.
  4. Once thawed, attempt to reset the boiler using the reset button.

Parts commonly replaced

  • Main Heat Exchanger
  • Condensate Pipe Insulation

Related codes

Full explanation for 25E
28

Your boiler has detected that there is not enough water pressure or the water isn't moving through the system correctly, causing it to shut down for safety.

High DIY-safe £120-280

What to check first

  1. Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.
  2. If the pressure is low, use the external filling loop to top up the system with water.
  3. Restart the boiler to see if the fault clears.

Parts commonly replaced

  • Low water pressure switch
  • Circulation pump
  • Pressure sensor

Related codes

Full explanation for 28
Showing 21–30 of 49
29E

Your boiler has stopped providing hot water because the temperature sensor responsible for tracking water heat has detected an unsafe level of overheating.

High Engineer only £90-180

Parts commonly replaced

  • DHW Temperature Sensor
  • Wiring Harness
  • Main PCB
Full explanation for 29E
30

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

High Engineer only £120-£350

Parts commonly replaced

  • Flue Thermistor
  • Heat Exchanger
  • Main PCB
Full explanation for 30
31

Your boiler has detected that the exhaust gases are not being monitored correctly and has shut down as a safety precaution.

High Engineer only £90-180

Parts commonly replaced

  • Flue Gas NTC Sensor
  • Wiring Loom

Related codes

Full explanation for 31
31E

Your boiler has lost its connection with the smart thermostat or controller, meaning they are no longer talking to each other.

High DIY-safe £90-250

What to check first

  1. Check that your smart thermostat or wall controller is powered on.
  2. Replace the batteries in your thermostat if it uses them.
  3. Restart your internet router if the heating system relies on a Wi-Fi bridge.
  4. Ensure the thermostat is within range of the boiler receiver.

Parts commonly replaced

  • Thermostat batteries
  • OpenTherm Bridge/Receiver
  • Smart Thermostat
  • Communication wiring
Full explanation for 31E
41E

Your boiler has detected that water is not circulating correctly through the system, causing an unusual temperature gap between the outgoing and returning pipes.

High DIY-safe £150-£350

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. Gently bleed your radiators to remove trapped air

Parts commonly replaced

  • Circulation pump
  • Flow and return thermistors
  • Main heat exchanger (de-scaling)
Full explanation for 41E
42E

Your boiler has detected an unusual temperature difference between internal sensors, suggesting that water isn't flowing correctly or a sensor is providing an incorrect reading.

High DIY-safe £120-280

What to check first

  1. Check that all radiator valves are fully open
  2. Check the boiler pressure gauge and top up to 1.5 bar if it is too low
  3. Bleed all radiators to remove trapped air which may be blocking water flow
  4. Reset the boiler to see if the fault clears

Parts commonly replaced

  • NTC Temperature Sensors
  • Central Heating Pump
  • Main Heat Exchanger (Descaling)
Full explanation for 42E
44E

Your boiler has detected an unusual temperature difference between the pipes, which usually means the water isn't flowing through the system correctly.

High DIY-safe £120-280

What to check first

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

Parts commonly replaced

  • Circulation Pump
  • NTC Temperature Sensors
  • Main Heat Exchanger (if blocked)

Related codes

Full explanation for 44E
46E

Your boiler has lost the ability to monitor its own water pressure levels, which has caused it to stop running as a safety precaution.

High Engineer only £120-210

Parts commonly replaced

  • Water pressure sensor (transducer)
  • Wiring harness

Related codes

Full explanation for 46E
E02

Your boiler is overheating because the water is not being pumped around the system correctly.

High Engineer only £180-£350

Parts commonly replaced

  • Circulation Pump
  • Printed Circuit Board (PCB)
  • Overheat Thermostat

Related codes

Full explanation for E02
E03

Your boiler has stopped working because it cannot correctly monitor the flow of water through the internal system.

High Engineer only £120-220

Parts commonly replaced

  • Flow sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for E03
Showing 31–40 of 49
E04

Your boiler is having trouble measuring the temperature of your tap water, which means it cannot heat your hot water correctly.

Medium Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) thermistor
  • NTC sensor
  • Wiring harness

Related codes

Full explanation for E04
E05

Your boiler has stopped working because the fan that helps remove exhaust gases is not spinning or communicating correctly with the system.

High Engineer only £180-£350

Parts commonly replaced

  • Fan unit
  • Air pressure switch
  • Main PCB

Related codes

Full explanation for E05
E06

Your boiler has detected that the water inside the heating system is getting too hot and has shut down as a safety precaution.

High DIY-safe £90-180

What to check first

  1. Ensure all radiator valves are fully open to allow water to flow.
  2. Check that the boiler pressure is between 1.0 and 1.5 bar on the gauge.
  3. Restart the boiler using the reset button once it has cooled down.

Parts commonly replaced

  • Central Heating NTC Temperature Sensor
  • Circulation Pump
  • Main Heat Exchanger (if scaled)

Related codes

Full explanation for E06
E08

Your boiler has detected that there is not enough water in the system to operate safely, which is usually caused by a small leak or air being bled from the radiators.

High DIY-safe £0-120

What to check first

  1. Locate the external filling loop beneath the boiler (usually a silver braided hose with small valves).
  2. Slowly open the valves to allow water into the system while watching the pressure gauge.
  3. Close the valves tightly once the pressure gauge reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure sensor

Related codes

Full explanation for E08
E09

Your boiler has shut down because its internal temperature has become too hot, which is a safety feature to prevent damage.

High DIY-safe £120-350

What to check first

  1. Check that your radiator valves are open
  2. Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar)
  3. Turn the boiler off and on again to see if the fault clears once it has cooled down

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Main Heat Exchanger

Related codes

Full explanation for E09
E10

Your boiler has too much water inside it, which is putting excess stress on the internal system.

Medium DIY-safe £0-120

What to check first

  1. Check that the filling loop valves are fully closed
  2. Bleed water from a radiator using a bleed key to reduce pressure
  3. Monitor the pressure gauge until it returns to between 1.0 and 1.5 bar
  4. Reset the boiler once the pressure is stabilised

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for E10
E13

Your boiler's internal computer has encountered a glitch or software failure that is preventing it from running safely.

High DIY-safe £250-450

What to check first

  1. Locate the power switch or fused spur for the boiler
  2. Turn the power off for 30 seconds
  3. Turn the power back on and press the 'Reset' button on the control panel

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Display Interface Module

Related codes

Full explanation for E13
E21

Your boiler has detected that the water returning from your radiators is too hot, which has caused the system to shut down for safety.

High Engineer only £120-250

Parts commonly replaced

  • CH Return NTC Sensor
  • Circulation Pump
  • Main Heat Exchanger

Related codes

Full explanation for E21
E22

Your boiler has shut down because the exhaust gases are getting too hot, which is a safety measure to protect the system and your home.

High Engineer only £120-350

Parts commonly replaced

  • Main Heat Exchanger
  • Flue Thermistor
  • Heat Exchanger De-scaler

Related codes

Full explanation for E22
E23

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

High Engineer only £120-£200

Parts commonly replaced

  • Flue Gas NTC Sensor
  • Wiring Harness
  • Main Control Board

Related codes

Full explanation for E23
Showing 41–49 of 49
E24

Your boiler has detected an issue with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating your home correctly.

High Engineer only £90-160

Parts commonly replaced

  • Central heating return NTC sensor
  • Wiring harness connection

Related codes

Full explanation for E24
E25

Your boiler has detected that the water inside the main heating unit has frozen due to extremely low temperatures, preventing it from starting up.

High DIY-safe £0-120

What to check first

  1. Check if the condensate pipe (the plastic pipe leading outside) is frozen and thaw it with warm water.
  2. Increase the thermostat setting and ensure the power is on to allow the boiler's internal frost protection to work.
  3. Gradually increase the room temperature to thaw the internal components naturally; do not use a blowtorch or direct flame.

Parts commonly replaced

  • Condensate pipe insulation
  • Main heat exchanger (if damaged by ice expansion)

Related codes

Full explanation for E25
E29

Your boiler has detected that the water used for your taps and showers is getting too hot, so it has shut down to prevent damage or scalding.

High Engineer only £90-180

Parts commonly replaced

  • DHW Temperature Sensor (NTC Thermistor)
  • DHW Heat Exchanger
  • Diverter Valve

Related codes

Full explanation for E29
E31

Your boiler is having trouble communicating with your smart thermostat or external controls, meaning it may not receive the signal to turn on.

High Engineer only £90-250

Parts commonly replaced

  • OpenTherm Interface
  • Main PCB
  • External Thermostat Receiver

Related codes

Full explanation for E31
E41

Your boiler has detected that the water leaving the unit is a significantly different temperature than the water returning to it, which usually means the water isn't circulating properly.

High DIY-safe £120-£350

What to check first

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

Parts commonly replaced

  • Circulation Pump
  • Flow/Return Thermistors
  • Main Heat Exchanger (Cleaning or Replacement)

Related codes

Full explanation for E41
E42

Your boiler has detected an unusual temperature difference between internal sensors, suggesting a flow or circulation issue.

High DIY-safe £120-280

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the system pressure is between 1.0 and 1.5 bar
  3. Try resetting the boiler to clear the temporary error

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Main Heat Exchanger

Related codes

Full explanation for E42
E43

Your boiler has detected that the temperature sensors for the water going out and coming back are too far apart or inconsistent, causing the system to stop for safety.

High Engineer only £120-£280

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Main PCB

Related codes

Full explanation for E43
E44

Your boiler has detected an unusual temperature difference between the internal sensors, which means it has stopped heating to prevent damage.

High Engineer only £120-220

Parts commonly replaced

  • Flow NTC sensor
  • Return NTC sensor
  • Circulation pump

Related codes

Full explanation for E44
E46

Your boiler's internal sensor has lost track of the system's water pressure, preventing it from heating your home safely.

High Engineer only £120-190

Parts commonly replaced

  • Water pressure sensor
  • Sensor wiring harness

Related codes

Full explanation for E46