Ideal Logic Combi 35 Fault codes & diagnostics

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

Combi Natural Gas 2009-2016 Discontinued
GC Number 47-348-58
Download the Ideal Logic Combi 35 manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Fault codes

All 5 documented codes

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c0

Your boiler has detected an internal issue and is prompting you to perform a manual reset to see if it can clear the error and restart successfully.

Medium DIY-safe

What to check first

  1. Locate the Reset button on the front control panel
  2. Press and hold the button for 3 to 5 seconds
  3. Wait for the boiler to cycle and check if the code clears and the burner ignites

Parts commonly replaced

  • Main PCB
  • Wiring harness
  • Ignition lead

Related codes

Full explanation for c0
c2

Your boiler's electronic memory card is not being recognised, which prevents the system from starting up safely.

High Engineer only £150-300

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB
Full explanation for c2
L 2

Your boiler has failed to light several times and has shut down for safety, meaning you currently have no heating or hot water.

High DIY-safe £100-£350

What to check first

  1. Check if your gas supply is active by testing another gas appliance like a hob.
  2. Check if your condensate pipe (the white plastic pipe outside) is frozen or blocked.
  3. Reset the boiler by turning the control knob to 'Reset' and holding for two seconds.

Parts commonly replaced

  • Gas valve
  • Ignition electrode
  • Flame sensing probe
  • Spark generator

Related codes

Full explanation for L 2
L1

Your boiler has switched itself off because the internal water temperature has become too hot, usually caused by a lack of water flow through the system.

High DIY-safe £120-£350

What to check first

  1. Check that your radiator valves are fully open
  2. Ensure your boiler pressure is between 1 and 1.5 bar on the gauge
  3. Reset the boiler by turning the control knob to 'RE' or pressing the reset button

Parts commonly replaced

  • Circulating pump
  • Thermistor (NTC sensor)
  • Main heat exchanger

Related codes

Full explanation for L1
L2

Your boiler has failed to light several times and has shut down for safety, meaning you currently have no heating or hot water.

High DIY-safe £100-£350

What to check first

  1. Check if your gas supply is active by testing another gas appliance like a hob.
  2. Check if your condensate pipe (the white plastic pipe outside) is frozen or blocked.
  3. Reset the boiler by turning the control knob to 'Reset' and holding for two seconds.

Parts commonly replaced

  • Gas valve
  • Ignition electrode
  • Flame sensing probe
  • Spark generator

Related codes

Full explanation for L2