Ravenheat Rsf Fault codes & diagnostics

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

Combi Natural Gas 24-28 kW 1997-2005 Discontinued

Replaced by: HE series

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Severity at a glance

Each cell = one fault code. Hover to identify.
45 High 4 Medium
Just want the most common Ravenheat Rsf 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, which means you will not have any heating or hot water until the issue is resolved.

High DIY-safe £150-350

What to check first

  1. Check that your gas supply is turned on and other gas appliances are working
  2. Press and hold the reset button for 5 seconds
  3. Ensure your credit meter has sufficient funds

Parts commonly replaced

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

Related codes

Full explanation for 01
02

Your boiler has detected an incorrect temperature reading and needs to be restarted to clear the error.

High DIY-safe £90-180

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 or turn the dial to 'R' and back.
  3. Wait for the boiler to complete its startup sequence and check if the code clears.

Parts commonly replaced

  • Negative Temperature Coefficient (NTC) Thermistor
  • Overheat Thermostat
  • Main PCB

Related codes

Full explanation for 02
02E

Your boiler has stopped working because water is not moving through the system as it should.

High DIY-safe £180-£350

What to check first

  1. Check that your home's central heating valves are fully open
  2. Inspect the boiler pressure gauge and top it up to 1.5 bar if it is too low
  3. Gently bleed your radiators to remove any trapped air

Parts commonly replaced

  • Circulation pump
  • Pump capacitor
  • Flow switch

Related codes

Full explanation for 02E
03E

Your boiler has detected an internal sensor failure and cannot safely monitor the movement of water, causing it to stop heating your home or water.

High Engineer only £120-£210

Parts commonly replaced

  • Flow sensor
  • NTC thermistor
  • Wiring harness

Related codes

Full explanation for 03E
04

Your boiler has switched itself off because it got too hot, likely due to a circulation issue or a faulty internal safety sensor.

High Engineer only £90-180

Parts commonly replaced

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

Related codes

Full explanation for 04
04E

Your boiler is struggling to provide hot water correctly because its internal thermometer for the hot water system has stopped working.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW NTC thermistor (sensor)
  • Wiring harness connecting the sensor

Related codes

Full explanation for 04E
05E

Your boiler has stopped working because the fan that removes waste gases is not spinning or communicating correctly with the main control board.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Main PCB

Related codes

Full explanation for 05E
06E

Your boiler has stopped working because the central heating sensor has detected that the water inside is getting too hot.

High DIY-safe £90-180

What to check first

  1. Check that all your radiator valves are fully open
  2. Ensure there is enough water pressure in the system by checking the gauge
  3. Turn the boiler off and back on again to see if the fault clears

Parts commonly replaced

  • Central heating thermistor (NTC sensor)
  • Circulation pump
  • Main heat exchanger (if scaled up)

Related codes

Full explanation for 06E
08E

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 silver filling loop underneath or near your boiler.
  2. Slowly open the valve or valves until you hear water entering the system.
  3. Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close the valves tightly.

Parts commonly replaced

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

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

High DIY-safe £100-280

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure there is enough water pressure in the system by checking the pressure gauge (aim for 1.5 bar).
  3. Switch the boiler off and back on again to attempt a manual reset once it has cooled down.

Parts commonly replaced

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

Related codes

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

Your boiler has too much water in the system, which puts extra strain on the internal components.

Medium DIY-safe

What to check first

  1. Check that the silver 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 reaches between 1.0 and 1.5 bar
  4. Reset the boiler once the pressure is back in the green zone

Parts commonly replaced

  • Filling loop valve
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for 10E
12

Your boiler has lost its ability to measure the temperature of the water in your radiators, which means it cannot safely heat your home.

High Engineer only £90-160

Parts commonly replaced

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

Your boiler's computer system has encountered a processing error and cannot communicate correctly with the internal controls.

High DIY-safe £180-350

What to check first

  1. Locate the reset button on the control panel
  2. Press and hold the reset button for 5 seconds
  3. Turn off the power supply to the boiler at the fused spur for one minute, then turn it back on

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring harness
Full explanation for 13E
17

Your boiler has stopped working because the fan that clears out exhaust gases is not receiving the correct amount of electrical power.

High Engineer only £180-£350

Parts commonly replaced

  • Fan Motor
  • Main Printed Circuit Board (PCB)
  • Wiring Loom

Related codes

Full explanation for 17
21E

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

High DIY-safe £90-180

What to check first

  1. Ensure all radiator valves (TRVs) are fully open to allow water to circulate.
  2. Check that the boiler pressure is between 1.0 and 1.5 bar.
  3. Reset the boiler by turning the control knob to the 'Reset' position for five seconds.

Parts commonly replaced

  • Return NTC Thermistor (Sensor)
  • Circulation Pump
  • Central Heating Filter Cleaning

Related codes

Full explanation for 21E
22E

Your boiler has detected that the exhaust gases are getting too hot, so it has shut down as a safety precaution.

High Engineer only £120-£350

Parts commonly replaced

  • Flue NTC Sensor
  • Main Heat Exchanger
  • Gas Valve (Calibration)

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 £90-180

Parts commonly replaced

  • Flue Gas Sensor (NTC)
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for 23E
24E

Your boiler has detected a problem with the sensor that monitors the temperature of the water coming back from your radiators, meaning it cannot control the heating correctly.

High Engineer only £90-180

Parts commonly replaced

  • Central heating return NTC sensor
  • Sensor wiring harness
  • Main PCB

Related codes

Full explanation for 24E
25E

Your boiler's main internal unit has become too cold and has likely frozen, preventing it from heating your home safely.

High DIY-safe £90-180

What to check first

  1. Turn the boiler off at the main electrical switch
  2. Thaw the internal pipework and heat exchanger using a hair dryer on a low setting or warm towels
  3. Once the boiler has reached room temperature, attempt to reset it

Parts commonly replaced

  • Main Heat Exchanger
  • Temperature NTC Sensors

Related codes

Full explanation for 25E
28

Your boiler has detected that there is not enough water pressure or movement to operate safely, causing the system to shut down.

High DIY-safe £80-280

What to check first

  1. Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.
  2. If the pressure is too low, use the filling loop valves to top up the water level.
  3. Ensure all radiator valves and the main isolation valves under the boiler are fully open.

Parts commonly replaced

  • Low water pressure switch
  • Circulation pump
  • Expansion vessel recharge

Related codes

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

Your boiler has detected that the water used for your taps is getting too hot and has shut down to prevent damage.

High DIY-safe £90-180

What to check first

  1. Turn the boiler off and wait 20 minutes for it to cool down
  2. Ensure your hot water temperature dial is not set to maximum
  3. Turn the boiler back on and press the reset button

Parts commonly replaced

  • DHW Temperature Sensor (NTC thermistor)
  • Main Heat Exchanger (if scaled up)
  • Diverter Valve

Related codes

Full explanation for 29E
30

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

High Engineer only £120-280

Parts commonly replaced

  • Flue NTC sensor
  • Main Heat Exchanger
  • Thermistor
Full explanation for 30
31

Your boiler has sensed that the gases escaping through the exhaust pipe are too hot or the sensor detecting them is broken, so it has shut down for safety.

High Engineer only £100-£190

Parts commonly replaced

  • Flue Gas NTC Sensor
  • Main PCB
  • Heat Exchanger cleaning/descaling

Related codes

Full explanation for 31
31E

Your boiler is having trouble 'talking' to your smart thermostat or external heater controls.

High Engineer only £90-250

Parts commonly replaced

  • OpenTherm Control Module
  • External Thermostat
  • Receiver Wiring Hub
Full explanation for 31E
41E

Your boiler has detected that water is not circulating correctly through the system, causing a heat imbalance.

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the central heating system pressure is between 1.0 and 1.5 bar
  3. Gently bleed air from your radiators using a radiator key

Parts commonly replaced

  • Circulation pump
  • Flow and return thermistors
  • Main heat exchanger (de-sludging)

Related codes

Full explanation for 41E
42E

Your boiler has detected an unusual temperature difference between internal sensors, suggesting water isn't flowing through the system correctly.

High Engineer only £120-350

Parts commonly replaced

  • Thermistor (NTC sensor)
  • Circulation Pump
  • Main Heat Exchanger

Related codes

Full explanation for 42E
44E

Your boiler has sensed a confusing temperature difference between parts of the system and has shut down as a safety precaution.

High Engineer only £120-280

Parts commonly replaced

  • NTC Temperature Sensor
  • Main Heat Exchanger
  • Circulation Pump

Related codes

Full explanation for 44E
46E

Your boiler has detected an issue with the sensor that monitors water levels, meaning it cannot confirm if there is enough internal pressure to run safely.

High Engineer only £120-£210

Parts commonly replaced

  • Water Pressure Sensor
  • Wiring Loom
Full explanation for 46E
E02

Your boiler has stopped working because the water isn't moving through the pipes as it should, causing it to overheat and shut down for safety.

High DIY-safe £180-£350

What to check first

  1. Check that your radiators are turned on and the valves are open
  2. Ensure the boiler pressure gauge is between 1 and 1.5 bar
  3. Try resetting the boiler to see if the error clears

Parts commonly replaced

  • Circulating Pump
  • Pump Capacitor
  • Main Heat Exchanger (if blocked)

Related codes

Full explanation for E02
E03

Your boiler has stopped working because it cannot correctly detect the water moving through the system to start the heating process.

High Engineer only £120-210

Parts commonly replaced

  • Flow sensor
  • Turbine sensor
  • Wiring harness

Related codes

Full explanation for E03
Showing 31–40 of 49
E04

Your boiler is having trouble measuring the temperature of your hot water, which means you may have no hot water or it may be inconsistent.

Medium Engineer only £90-160

Parts commonly replaced

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

Related codes

Full explanation for E04
E05

Your boiler has stopped working because the internal fan, which safely exhausts fumes, is not starting or communicating correctly.

High Engineer only £150-£350

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Main PCB

Related codes

Full explanation for E05
E06

Your boiler has shut down because a temperature sensor has detected that the water in your heating system is getting too hot.

High Engineer only £90-180

Parts commonly replaced

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

Related codes

Full explanation for E06
E08

Your boiler has detected that the water pressure in the system is too low and has safely shut down to prevent damage.

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 valve(s) until you hear water entering the system.
  3. Watch the pressure gauge and close the valves tightly once it reaches 1.5 bar.
  4. Reset the boiler to clear the fault code.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for E08
E09

Your boiler has detected that it is getting too hot and has shut itself down for safety.

High DIY-safe £100-280

What to check first

  1. Wait for the boiler to cool down for at least 30 minutes
  2. Ensure all radiator valves are fully open
  3. Check that your system water pressure is between 1.0 and 1.5 bar
  4. Press the reset button on the control panel

Parts commonly replaced

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

Related codes

Full explanation for E09
E10

Your boiler has too much water in the system, which puts extra stress on the internal components and needs to be lowered.

Medium DIY-safe £60-140

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 and 1.5 bar
  4. Reset the boiler to clear the fault code

Parts commonly replaced

  • Filling loop valve
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for E10
E13

Your boiler's internal computer has encountered a software glitch or communication failure.

High DIY-safe £180-350

What to check first

  1. Locate the reset button on the control panel
  2. Press and hold the reset button for 5 seconds
  3. Turn the power to the boiler off at the fused spur switch, wait 30 seconds, and turn it back on

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Control Panel Overlay

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 £90-180

Parts commonly replaced

  • CH Return Temperature Sensor (NTC)
  • Circulation Pump
  • Main PCB

Related codes

Full explanation for E21
E22

Your boiler has detected that the exhaust gases are getting too hot and has shut down as a safety precaution.

High Engineer only £120-280

Parts commonly replaced

  • Flue Thermistor (NTC Sensor)
  • Main Heat Exchanger
  • Fan

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 £120-190

Parts commonly replaced

  • Flue Gas Sensor
  • Wiring harness

Related codes

Full explanation for E23
Showing 41–49 of 49
E24

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

High Engineer only £90-160

Parts commonly replaced

  • Central heating return thermistor (NTC sensor)
  • Connecting wiring harness

Related codes

Full explanation for E24
E25

Your boiler's internal tank has detected that it is frozen or too cold to operate safely.

High DIY-safe £0-120

What to check first

  1. Check if your external condensate pipe is frozen and gently thaw it with warm water
  2. Increase the room thermostat setting to encourage the boiler to start
  3. Switch the electricity to the boiler off and back on to reset the system
  4. Ensure any loft or garage insulation around pipes is intact

Parts commonly replaced

  • None (Thawing required)
  • NTC Temperature Sensor
  • Condensate Trace Heater

Related codes

Full explanation for E25
E29

Your boiler has detected that the water used for your taps and showers is getting too hot and has shut down as a safety precaution.

High Engineer only £90-180

Parts commonly replaced

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

Related codes

Full explanation for E29
E31

Your boiler's internal computer is having trouble talking to your smart thermostat or the control board, preventing the heating from starting.

High Engineer only £100-280

Parts commonly replaced

  • OpenTherm Interface
  • Main PCB
  • Thermostat wiring
Full explanation for E31
E41

Your boiler has detected that water is not circulating correctly between the flow and return pipes, causing a temperature imbalance.

High DIY-safe £100-£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. Bleed all radiators to remove trapped air

Parts commonly replaced

  • Circulation pump
  • Flow and return thermistors
  • Main heat exchanger (de-scaling)

Related codes

Full explanation for E41
E42

Your boiler has detected an unusual temperature difference between internal sensors, suggesting water isn't flowing through the system correctly.

High Engineer only £120-280

Parts commonly replaced

  • NTC Temperature Sensors
  • Circulation Pump
  • Main PCB

Related codes

Full explanation for E42
E43

Your boiler has sensed a confusing difference between its internal temperature readings and has shut down as a safety precaution.

High Engineer only £90-250

Parts commonly replaced

  • Flow NTC sensor
  • Return NTC sensor
  • Main PCB

Related codes

Full explanation for E43
E44

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

High Engineer only £90-280

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Main PCB

Related codes

Full explanation for E44
E46

Your boiler has detected an issue with the sensor that monitors internal water pressure, meaning it cannot confirm if there is enough water to run safely.

High Engineer only £120-220

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for E46