Sime Murelle Advanced HE Combi Fault codes & diagnostics

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

Combi Natural Gas 2017 onwards
GC Numbers 47-283-5347-283-5447-283-83
Download the Sime Murelle Advanced HE Combi manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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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.
3 Emergency 22 High 1 Medium
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
47-283-83 MURELLE ADVANCED HE 40 MkII 2017–present
Just want the most common Sime Murelle Advanced HE Combi faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 26 documented codes

Tap any card for details

ALL 02

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

High DIY-safe £0-£100

What to check first

  1. Locate the filling loop (a flexible silver hose) underneath the boiler or near the pipework.
  2. Slowly open the valves on both ends of the loop until you hear water entering the system.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (usually between 1.0 and 1.5 bar).
  4. Close both valves tightly and check that the boiler restarts automatically.

Parts commonly replaced

  • Filling loop
  • Pressure gauge
  • Pressure relief valve

Related codes

Full explanation for ALL 02
ALL 03

Your boiler has detected that the water pressure inside the heating system is currently too high, which prevents it from operating safely.

High DIY-safe

What to check first

  1. Locate a radiator in your home that has a bleed valve.
  2. Place a cloth and a container under the valve.
  3. Use a radiator key to slowly release air and a small amount of water until the pressure gauge on the front of your boiler returns to the green zone (typically 1.0 to 1.5 bar).

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for ALL 03
ALL 04

Your boiler has lost the ability to measure the temperature of the hot water it produces, so it has safely shut down the hot water function to prevent overheating.

Medium Engineer only £120-180

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC Temperature Sensor

Related codes

Full explanation for ALL 04
ALL 05

Your boiler's temperature sensor is providing incorrect readings or has disconnected, which has caused the system to shut down to prevent overheating.

High Engineer only £120-200

Parts commonly replaced

  • NTC Delivery Sensor
  • Wiring harness

Related codes

Full explanation for ALL 05
ALL 06

Your boiler has attempted to start but is unable to detect a flame, causing it to shut down for safety.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Gas valve

Related codes

Full explanation for ALL 06
ALL 07

Your boiler has detected that it has become dangerously hot and has shut itself down to prevent any damage or safety issues.

High Engineer only £120-250

Parts commonly replaced

  • Safety limit thermostat
  • System pump
  • Heat exchanger

Related codes

Full explanation for ALL 07
ALL 08

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

High Engineer only £150-£300

Parts commonly replaced

  • Flame rectification electrode
  • Ignition lead
  • PCB

Related codes

Full explanation for ALL 08
ALL 09

Your boiler has detected that water is not flowing around your heating system properly, so it has shut down to prevent damage.

High DIY-safe £120-250

What to check first

  1. Check your central heating 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 on again using the reset button to see if the error clears.

Parts commonly replaced

  • Circulation pump
  • Flow switch
  • Diverter valve

Related codes

Full explanation for ALL 09
ALL 10

Your boiler's control system is struggling to read a secondary temperature signal, causing it to stop operating as a safety precaution.

High Engineer only £150-250

Parts commonly replaced

  • NTC Sensor
  • Wiring harness

Related codes

Full explanation for ALL 10
ALL 11

Your boiler has lost the electrical connection to the part that regulates its gas flow, meaning it cannot safely ignite or produce heat.

High Engineer only £120-220

Parts commonly replaced

  • Gas valve wiring harness
  • Gas valve modulator coil
  • Gas valve assembly

Related codes

Full explanation for ALL 11
Showing 11–20 of 26
ALL 12

Your boiler's electronic control system is confused about its installation setup, which is preventing it from starting safely.

High Engineer only £100-£200

Parts commonly replaced

  • PCB (Printed Circuit Board)
  • Wiring harness

Related codes

Full explanation for ALL 12
ALL 13

Your boiler has detected that the temperature of the exhaust fumes leaving the unit is too high, so it has safely shut itself down to prevent damage.

Emergency Engineer only £150-300

Parts commonly replaced

  • Flue gas sensor
  • Primary heat exchanger
  • Printed Circuit Board

Related codes

Full explanation for ALL 13
ALL 14

Your boiler is struggling to accurately measure the temperature of the gases leaving the unit, so it has safely shut itself down to prevent any potential issues.

High Engineer only £150-250

Parts commonly replaced

  • Flue gas sensor
  • Wiring harness
  • PCB

Related codes

Full explanation for ALL 14
ALL 15

Your boiler has stopped working because the communication wire between the main control board and the internal fan has come loose or is not properly connected.

High Engineer only £120-200

Parts commonly replaced

  • Fan wiring harness
  • Fan assembly
  • PCB

Related codes

Full explanation for ALL 15
ALL 18

Your boiler has detected that water produced during the heating process is not draining away properly and is backing up inside the system.

High Engineer only £120-200

Parts commonly replaced

  • Condensate trap
  • Condensate pipework
  • Siphon

Related codes

Full explanation for ALL 18
ALL 28

Your boiler has been manually reset too many times in a short period and has now locked itself for safety to prevent further damage.

High Engineer only £100-250

Parts commonly replaced

  • Main PCB
  • Control Interface

Related codes

Full explanation for ALL 28
ALL 37

Your boiler is struggling because the electricity supply it is receiving is weaker than it should be.

High Engineer only £100-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for ALL 37
ALL 40

Your boiler has detected that the electricity supply coming into your home is not at the standard frequency it requires to run safely and correctly.

High Engineer only £120-250

Parts commonly replaced

  • Main Control PCB

Related codes

Full explanation for ALL 40
ALL 41

Your boiler is repeatedly failing to keep a flame lit, so it has locked itself out for safety reasons.

High Engineer only £150-350

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe

Related codes

Full explanation for ALL 41
ALL 42

Your boiler's control panel has detected that one of the buttons on the display is stuck or malfunctioning, preventing the system from operating normally.

High Engineer only £120-250

Parts commonly replaced

  • Control panel PCB
  • Interface board
  • User interface ribbon cable

Related codes

Full explanation for ALL 42
Showing 21–26 of 26
ALL 43

Your boiler's smart thermostat and the main heating unit are unable to send messages to each other, so the system has stopped working to prevent incorrect operation.

High Engineer only £120-250

Parts commonly replaced

  • OpenTherm interface board
  • Main PCB
  • Communication wiring harness

Related codes

Full explanation for ALL 43
ALL 62

Your boiler has lost its internal settings and needs a specific electronic recalibration to operate correctly again.

High Engineer only £100-200

Parts commonly replaced

  • Control board
  • Gas valve

Related codes

Full explanation for ALL 62
ALL 72

Your boiler is confused because a sensor that monitors the temperature of the water leaving the unit has moved out of its proper position or has come loose.

High Engineer only £120-200

Parts commonly replaced

  • Delivery NTC sensor
  • Sensor wiring harness

Related codes

Full explanation for ALL 72
ALL 81

Your boiler has detected an issue while trying to light the flame and has shut itself down to keep your home safe.

Emergency Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame detection probe

Related codes

Full explanation for ALL 81
ALL 83

Your boiler has detected an issue with the way it is burning fuel, so it has temporarily shut down for your safety.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame sensor
  • Gas valve
  • Flue seals

Related codes

Full explanation for ALL 83
ALL 96

Your boiler has detected that the exhaust pipe leading outside is blocked or restricted, so it has safely shut itself down to prevent fumes from building up inside your home.

Emergency Engineer only £120-250

Parts commonly replaced

  • Flue assembly
  • Fan unit
  • Air pressure switch

Related codes

Full explanation for ALL 96
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