Ideal Independent C24 Fault codes & diagnostics

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

Combi Natural Gas 24 kW 2009-2013 Discontinued

Replaced by: Independent Combi

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Severity at a glance

Each cell = one fault code. Hover to identify.
8 High

All 8 documented codes

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L1

Your boiler has lost communication with its internal memory chip, meaning it cannot operate safely until the settings are restored or the component is replaced.

High Engineer only £150-300

Parts commonly replaced

  • Boiler Control Card (BCC)
  • Wiring Harness

Related codes

L2

Your boiler is trying to start but cannot get the flame to light or stay lit.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Ignition lead

Related codes

L3

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

High DIY-safe £0-£120

What to check first

  1. Locate the external filling loop, which is a silver braided hose under the boiler.
  2. Open the small black or blue valves on either end of the hose to allow mains water into the system.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (usually around 1.5 bar).
  4. Close both valves tightly to stop the flow of water.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure sensor
L4

Your boiler has detected that the flame inside has gone out unexpectedly, so it has shut itself down to keep your home safe.

High Engineer only £120-250

Parts commonly replaced

  • Ignition lead
  • Electrode assembly
  • Gas valve

Related codes

L5

Your boiler has detected that the internal mechanism responsible for safely venting exhaust gases is not working correctly, so it has safely shut itself down to prevent operation.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

L6

Your boiler has stopped working because a sensor that measures the temperature of the water flowing out to your radiators is not sending a correct signal.

High Engineer only £120-200

Parts commonly replaced

  • Flow NTC Thermistor

Related codes

L7

Your boiler is struggling to accurately measure the temperature of the water returning to it, preventing it from heating your home or water correctly.

High Engineer only £120-200

Parts commonly replaced

  • Return NTC thermistor

Related codes

None

Your boiler is struggling to accurately measure the temperature of the water being heated, which is preventing it from running your heating and hot water properly.

High Engineer only £120-200

Parts commonly replaced

  • NTC Thermistor
  • Wiring Harness