Common problems guide

The most common Sime Murelle HE 110R problems

The faults most likely to send a Sime Murelle HE 110R into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

6 documented codes
6 most common
2 DIY-safe checks
4 engineer needed

The 6 most common faults

01
E4 High DIY-safe

Your boiler has detected that the water pressure inside the system is too low to operate safely.

What to try first

Locate the filling loop (usually a silver braided hose with one or two valves underneath the boiler).Slowly open the valve(s) to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Ensure the valve(s) are tightly closed and check the boiler display to see if the error has cleared.

Est. cost
£0-80
Parts
Filling loop, Pressure relief valve, Pressure transducer
Full guide for E4
02
E7 High DIY-safe

Your boiler has detected that the water pressure inside the heating system is too low to operate safely.

What to try first

Locate the external filling loop, usually a flexible braided hose under the boiler.Open the filling valve slowly until the pressure gauge on the front of the boiler reads between 1 and 1.5 bar.Close the valve tightly to prevent over-pressurisation.

Est. cost
£0-£100
Parts
Pressure relief valve, Pressure gauge, Filling loop
Full guide for E7
03
E3 High Engineer

Your boiler has detected an issue with the water circulation system, meaning it cannot effectively move heat around your home or to your taps.

Est. cost
£150-300
Parts
Circulation pump, System filter, Flow sensor
Full guide for E3
04
E6 High Engineer

Your boiler has detected an issue with the water temperature or flow sensor, meaning it has shut down to protect itself from overheating.

Est. cost
£150-250
Parts
NTC Temperature Sensor, Flow Sensor, Main PCB
Full guide for E6
05
E8 High Engineer

Your boiler has detected an issue with the water pressure system, which is preventing it from heating your home or water.

Est. cost
£120-250
Parts
Pressure sensor, Expansion vessel, Filling loop
Full guide for E8
06
E1 Medium Engineer

Your boiler has lost the ability to read the temperature from an external sensor, which is preventing it from heating your home properly.

Est. cost
£120-200
Parts
External temperature sensor, Wiring harness
Full guide for E1
Parts most often replaced

on the Sime Murelle HE 110R

Filling loopPressure relief valvePressure transducerPressure gaugeCirculation pumpSystem filter

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Sime shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
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See the full 6-code list for the Sime Murelle HE 110R

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →