BoilerFaultCodes ALL 01
FLUE TEMPERATURE ALARM
Sime Murelle HE Combi with Cylinder Fault codes & diagnostics
13 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 2005-2014 Discontinued
GC Numbers 47-283-1047-283-1147-283-12
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Severity at a glance
Each cell = one fault code. Hover to identify. 1 Emergency
8 High
4 Unrated
Just want the most common Sime Murelle HE Combi with Cylinder faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 13 documented codes
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ALL 02 Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
What to check first
- Locate the filling loop (usually a silver braided hose with one or two valves) underneath the boiler.
- Open the valve(s) slowly to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.
- Close the valve(s) tightly to stop the flow of water and check the boiler display to see if the error clears.
Parts commonly replaced
- Filling loop
- Pressure relief valve
- Expansion vessel
Related codes
ALL 03 Your boiler has detected that the water pressure inside your heating system is too high for it to operate safely.
Your boiler has detected that the water pressure inside your heating system is too high for it to operate safely.
What to check first
- Locate a radiator in your home, preferably one upstairs.
- Place a cloth or small container under the radiator bleed valve.
- Open the bleed valve slightly with a radiator key to let water out until the pressure gauge on the boiler drops to between 1 and 1.5 bar, then close the valve tightly.
Parts commonly replaced
- Pressure relief valve
- Pressure sensor
- Filling loop
Related codes
ALL 04
D.H.W. SENSOR ALARM
ALL 05 Your boiler has stopped working because it is unable to accurately measure the temperature of the water used for your heating system.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water used for your heating system.
Parts commonly replaced
- Central heating NTC thermistor
- Wiring harness
Related codes
ALL 06 Your boiler has detected a safety-related issue and has automatically shut down to prevent damage or dangerous operation.
Your boiler has detected a safety-related issue and has automatically shut down to prevent damage or dangerous operation.
Parts commonly replaced
- Ignition electrode
- Gas valve
- PCB
Related codes
ALL 07 Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or overheating.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or overheating.
Parts commonly replaced
- Safety thermostat
- Pump
- Diverter valve
- System filter
Related codes
ALL 08 Your boiler has failed to light the burner or keep it running, so it has safely shut down to prevent unburnt gas from building up.
Your boiler has failed to light the burner or keep it running, so it has safely shut down to prevent unburnt gas from building up.
Parts commonly replaced
- Ignition electrode
- Flame rectification probe
- Gas valve
- PCB
Related codes
ALL 09 Your boiler is struggling to move water around your heating system, which has caused it to shut down to prevent internal damage.
Your boiler is struggling to move water around your heating system, which has caused it to shut down to prevent internal damage.
Parts commonly replaced
- Central heating pump
- Flow switch
- System filter
Related codes
ALL 10 Your boiler is struggling to detect the temperature of the water coming from your hot water tap, which means it will likely stop producing hot water until it is fixed.
Your boiler is struggling to detect the temperature of the water coming from your hot water tap, which means it will likely stop producing hot water until it is fixed.
Parts commonly replaced
- Domestic Hot Water (DHW) NTC Temperature Sensor
Related codes
ALL 13
ACTIVATION OF THE EXHAUST FUMES SENSOR ERROR
ALL 14 Your boiler has detected that hot exhaust gases are not escaping correctly, which could pose a safety risk, so it has shut itself down to protect your home.
Your boiler has detected that hot exhaust gases are not escaping correctly, which could pose a safety risk, so it has shut itself down to protect your home.
Parts commonly replaced
- Flue thermostat
- Flue sensor wiring loom
- Main PCB
Related codes
ALL 15
FAN ERROR