Heatline S24 / S30 Fault codes & diagnostics

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

Combi Natural Gas 24-30 kW Discontinued
GC Numbers 47-157-0247-157-03
Download the Heatline S24 / S30 manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. 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

Fault on DHW sensor

Your boiler is struggling to detect the temperature of the water coming out of your hot taps, which means it cannot heat your hot water correctly.

Medium Engineer only £120-200

Parts commonly replaced

  • DHW NTC thermistor sensor
  • Wiring harness
Full explanation for Fault on DHW sensor
Overheat Thermostat

Your boiler has switched itself off because it has become too hot internally and needs to be reset by a professional to ensure it is operating safely.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Central heating pump
  • PCB
Full explanation for Overheat Thermostat