Halstead Ace High Fault codes & diagnostics

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

Regular Natural Gas 20 kW 2006-2010 Discontinued
Download the Halstead Ace High manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Fault codes

All 2 documented codes

Tap any card for details

Ignition Lock-out

Your boiler has stopped working because it cannot light the flame required to produce heat or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Full explanation for Ignition Lock-out
OVERHEAT THERMOSTAT

Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage or safety issues.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Pump
  • Diverter valve
  • System filter
Full explanation for OVERHEAT THERMOSTAT
Status & diagnostic codes

2 operating states & engineer diagnostics

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

C12 Diagnostic Your boiler has lost its internal settings, meaning it no longer knows how to correctly identify or operate its own hardware. C32 Diagnostic Your boiler has lost its internal configuration settings and no longer recognises how it should operate.