Ideal Logic Max Combi C24P Fault codes & diagnostics

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

Combi LPG 2018-present
GC Number 47-349-55
No manual available yet We don't hold the official service manual for this model yet. We're sourcing it.

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Severity at a glance

Each cell = one fault code. Hover to identify.
16 High 1 Medium
Fault codes

All 17 documented codes

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4.5

Your boiler has detected that the water pressure inside the system is too low to run safely and has switched itself off.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually blue-handled levers) underneath the boiler.
  2. Slowly open the valves until you hear water entering the system.
  3. Watch the pressure gauge and close the valves when the needle reaches 1.5 bar.
  4. Restart the boiler if it does not reset automatically.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure sensor

Related codes

Full explanation for 4.5
4.7

Your boiler has stopped working because the internal fan, which safely clears exhaust fumes, is not running correctly.

High Engineer only £280-450

Parts commonly replaced

  • Fan Assembly
  • Main PCB
  • Wiring Loom

Related codes

Full explanation for 4.7
4.8

Your boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, preventing it from heating your home safely.

High Engineer only £90-160

Parts commonly replaced

  • Flow thermistor (NTC sensor)
  • Wiring harness / connector
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 4.8
4.9

Your boiler has detected an issue with the sensor that monitors the temperature of the water returning to the unit, likely causing it to shut down for safety.

High Engineer only £90-160

Parts commonly replaced

  • Return Thermistor (NTC Sensor)
  • Wiring harness
  • Main PCB

Related codes

Full explanation for 4.9
4.15

Your boiler is heating your radiators normally, but it is failing to provide hot water when you turn on your taps.

Medium Engineer only £120-£250

Parts commonly replaced

  • Diverter Valve Actuator Motor
  • Diverter Valve Cartridge
  • DHW Flow Turbine

Related codes

Full explanation for 4.15
C0

Your boiler's internal memory chip is not communicating correctly with the main computer, preventing the boiler from starting safely.

High Engineer only £150-250

Parts commonly replaced

  • Boiler Control Card (BCC)
  • Wiring harness

Related codes

Full explanation for C0
C2

Your boiler has lost its 'internal brain' or setup data, meaning it doesn't know how to operate your heating system correctly.

High Engineer only £120-250

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main Control PCB

Related codes

Full explanation for C2
F and 1

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

High DIY-safe

What to check first

  1. Locate the filling loop underneath your boiler or check the built-in keyless filling link.
  2. Open the valves slowly to allow mains water into the system until the pressure gauge reads between 1 and 1.5 bar.
  3. Close the valves firmly and press the reset button on your boiler.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor

Related codes

Full explanation for F and 1
F and 2

Your boiler's flame has unexpectedly gone out while trying to run, which safely shuts down the system.

High Engineer only £90-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Sump trap
  • Main PCB

Related codes

Full explanation for F and 2
F and 3

Your boiler has detected an issue with the internal fan that safely removes combustion gases, causing it to lock out for safety.

High Engineer only £150-300

Parts commonly replaced

  • Flue
  • Air pressure switch
  • Fan assembly
  • PCB

Related codes

Full explanation for F and 3
F4

Your boiler has detected an issue with the sensor that measures the temperature of the water leaving the unit, preventing it from heating your home safely.

High Engineer only £90-180

Parts commonly replaced

  • Flow thermistor (NTC sensor)
  • Wiring harness
  • Main PCB

Related codes

Full explanation for F4
F5

Your boiler has detected an issue with the sensor that monitors the temperature of the water returning from your radiators.

High Engineer only £100-£180

Parts commonly replaced

  • Return Thermistor (NTC)
  • Wiring Harness

Related codes

Full explanation for F5
F7

Your boiler has stopped working because the electrical power coming into your home is at a lower voltage than it needs to operate safely.

High DIY-safe £0-120

What to check first

  1. Check if other appliances in your home are acting strangely or lights are flickering
  2. Contact your electricity network provider to report a potential power supply issue
  3. Once the external power issue is resolved, reset the boiler using the 'RE' dial or button

Parts commonly replaced

  • External mains supply (Power Grid)
  • Printed Circuit Board (PCB)

Related codes

Full explanation for F7
L and 5

Your boiler has temporarily locked itself out for safety after registering too many automatic resets in a short space of time.

High Engineer only £100-250

Parts commonly replaced

  • PCB
  • Ignition Lead
  • Gas Valve

Related codes

Full explanation for L and 5
L and 6

Your boiler has mistakenly detected a flame inside when it should be switched off, so it has safely locked itself out to prevent any issues.

High Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Main printed circuit board (PCB)

Related codes

Full explanation for L and 6
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 tried to light several times but cannot establish a flame, meaning it has shut down for safety to prevent gas build-up.

High DIY-safe £100-280

What to check first

  1. Check if your gas supply is active by testing another gas appliance like a hob.
  2. If you have a prepay meter, ensure you have sufficient credit.
  3. In freezing temperatures, check if the external condensate pipe has frozen.
  4. Reset the boiler by turning the mode knob to 'RE' and back to your desired setting.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Ignition Lead
  • Ionisation Probe

Related codes

Full explanation for L2
Status & diagnostic codes

2 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

F9 Diagnostic Your boiler’s internal control board has lost its configuration or is brand new and hasn't been programmed yet to tell it which model it is. P1 Diagnostic Your boiler is displaying a service setting notification to run the pump at maximum speed, which usually indicates an installation or maintenance mode rather than a dangerous mechanical failure.
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