Chaffoteaux 80/100 Fault codes & diagnostics

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

Combi Natural Gas 24-29 kW 1994-2003 Discontinued

Replaced by: Chaffoteaux Britony

Download the Chaffoteaux 80/100 manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses indicator light combinations

Note which lights are on, off, or flashing and at what speed. Match the combination to the cards below. Do not reset until you have noted the pattern. How to read fault codes →

All 5 documented codes

Tap any card for details

Red indicator

Your boiler has stopped working because it cannot light the gas burner or keep it burning.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame sensor
  • PCB
Red lockout indicator

Your boiler has failed to light the flame, so it has safely shut itself down to prevent gas from building up.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame sensor
  • Gas valve
  • PCB
Lockout

Your boiler has stopped working because it failed to light or stay lit, and it needs a manual restart to try again.

High DIY-safe £100-250

What to check first

  1. Locate the reset button (marked 25 on your control panel).
  2. Press and hold the reset button for 2-3 seconds.
  3. Wait to see if the boiler ignites and the red light stops flashing.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe
Overheat detection

Your boiler has shut itself down because it detected that it is running too hot, indicating a potential circulation or sensor problem.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Pump
  • Diverter valve
  • Primary heat exchanger
Red LED

Your boiler has stopped working because it failed to start or got too hot, and it now needs to be manually restarted to begin operating again.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Overheat thermostat
  • PCB

1 operating states & engineer diagnostics

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