Sime Murelle HE 110R Fault codes & diagnostics

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

Heat Only Natural Gas 2010-present
Download the Sime Murelle HE 110R manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
5 High 1 Medium
Just want the most common Sime Murelle HE 110R faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 6 documented codes

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E1

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

Medium Engineer only £120-200

Parts commonly replaced

  • External temperature sensor
  • Wiring harness

Related codes

Full explanation for E1
E3

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

High Engineer only £150-300

Parts commonly replaced

  • Circulation pump
  • System filter
  • Flow sensor

Related codes

Full explanation for E3
E4

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

High DIY-safe £0-80

What to check first

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

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure transducer

Related codes

Full explanation for E4
E6

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

High Engineer only £150-250

Parts commonly replaced

  • NTC Temperature Sensor
  • Flow Sensor
  • Main PCB

Related codes

Full explanation for E6
E7

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

High DIY-safe £0-£100

What to check first

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

Parts commonly replaced

  • Pressure relief valve
  • Pressure gauge
  • Filling loop

Related codes

Full explanation for E7
E8

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

High Engineer only £120-250

Parts commonly replaced

  • Pressure sensor
  • Expansion vessel
  • Filling loop

Related codes

Full explanation for E8
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