Ideal Mexico Super CF3/125 Fault codes & diagnostics

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

Natural Gas 2001 Discontinued
GC Number 41-348-20
Download the Ideal Mexico Super CF3/125 manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
6 High
Fault codes

All 6 documented codes

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47

Your boiler is unable to start the small pilot flame needed to ignite the main heating system.

High Engineer only £100-£250

Parts commonly replaced

  • Thermocouple
  • Pilot Injector
  • Gas Control Valve
  • Ignition Electrode
Full explanation for 47
48

Your boiler is failing to keep the pilot light burning after you let go of the ignition button, meaning the heating cannot start.

High Engineer only £90-180

Parts commonly replaced

  • Thermocouple
  • Gas control valve
  • Overheat thermostat

Related codes

Full explanation for 48
49

Your boiler has successfully lit its pilot light, but the main burner is failing to ignite because it is not receiving the main supply of gas.

High Engineer only £150-250

Parts commonly replaced

  • Gas valve
  • PCB
  • Thermocouple

Related codes

Full explanation for 49
51

Your boiler's pilot light is failing to stay ignited after you try to light it, meaning the main burner cannot start to provide heat.

High Engineer only £90-180

Parts commonly replaced

  • Thermocouple
  • Overheat thermostat
  • Gas control valve
Full explanation for 51
52

Your boiler has managed to start the small pilot flame, but the main burner fails to ignite to provide full heating.

High Engineer only £120-£350

Parts commonly replaced

  • Gas valve
  • Main gas injector
  • Electronic control board
Full explanation for 52
Loss of system water pressure

Your boiler is losing the water it needs to heat your home, which is likely caused by a slow leak somewhere in your radiators or pipework.

High DIY-safe £75-200

What to check first

  1. Check all radiator valves and visible pipework for signs of dampness or drips
  2. Locate the external filling loop (usually a silver flexible hose) and carefully top up the pressure until the needle matches the red arrow
  3. Monitor the gauge and contact a professional if the needle continues to drop regularly

Parts commonly replaced

  • External filling loop
  • Radiator valve seals
  • Automatic air vent
Full explanation for Loss of system water pressure
Status & diagnostic codes

5 operating states & engineer diagnostics

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

E01 507 Diagnostic Your boiler has detected an issue with the valve that controls the flow of gas, meaning it cannot ignite to provide heat or hot water. E01 530 Diagnostic Your boiler is struggling to clear fumes properly because an internal metal part designed to guide exhaust gases is likely out of position or damaged. E01 540 Diagnostic Your boiler has detected an issue with the internal metal plate that manages airflow, which may prevent the unit from venting exhaust gases safely. E01 553 Diagnostic Your boiler has failed to ignite or stay lit, which means you currently have no heating or hot water, and a gas-safe engineer is required to investigate the internal ignition system. E01-507 Diagnostic Your boiler is failing to detect a flame because the internal component responsible for controlling the fuel supply is not operating correctly.