Ferroli Domi Compact Fault codes & diagnostics

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

Combi Natural Gas 24-30 kW 2006-2012 Discontinued
GC Numbers 47-267-3747-267-38

Replaced by: DomiCondens

Download the Ferroli Domi Compact manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
1 Emergency 4 High 1 Low
Just want the most common Ferroli Domi Compact faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 6 documented codes

Tap any card for details

LED / flash-pattern codes
5 (Flashing Light)

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

High DIY-safe £0-£80

What to check first

  1. Locate the filling loop (a silver flexible hose with one or two valves) underneath the boiler.
  2. Open the valve(s) slowly to allow cold mains water into the system while watching the pressure gauge.
  3. Close the valve(s) tightly once the needle reaches 1.5 bar, then turn the boiler off and on again to clear the fault.

Parts commonly replaced

  • External filling loop
  • Pressure relief valve
  • Pressure sensor

Related codes

Full explanation for 5 (Flashing Light)
Digital codes
F1

Your boiler has stopped working because it failed to ignite the gas flame required to heat your water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Full explanation for F1
F3

Your boiler has detected an issue with the airflow system or flue, causing it to shut down for safety reasons.

High Engineer only £120-250

Parts commonly replaced

  • Air pressure switch
  • Flue fan
  • Venturi

Related codes

Full explanation for F3
F5

Your boiler has detected a temporary issue with the air vent or exhaust system and is pausing itself to stay safe, but it should restart on its own once the condition clears.

Low Engineer only £100-250

Parts commonly replaced

  • Air pressure switch
  • Flue fan
  • Venturi

Related codes

Full explanation for F5
F37

Your boiler has detected that the water pressure inside the system is too low, so it has temporarily turned itself off to prevent any damage.

High DIY-safe £80-120

What to check first

  1. Locate the filling loop (a silver flexi-hose with one or two valves) underneath your boiler.
  2. Open the valve(s) slowly to let water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Ensure both valves are fully closed again to stop the water flow.

Parts commonly replaced

  • Pressure gauge
  • Filling loop
  • Pressure relief valve

Related codes

Full explanation for F37
F50

Your boiler has lost its connection to the gas control component, preventing it from safely starting up to provide heat or hot water.

Emergency Engineer only £120-250

Parts commonly replaced

  • Gas valve wiring harness
  • Gas valve assembly
  • PCB

Related codes

Full explanation for F50
Status & diagnostic codes

5 operating states & engineer diagnostics

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

4 (Flashing Light) Status Your boiler is perfectly healthy and is simply waiting for a signal from your thermostat to turn on the heating. 4 (Permanent Light) Status Your boiler is currently operating normally and is actively heating your radiators. 5 (Permanent Light) Status Your boiler is operating normally and is receiving power as expected. LED4 Permanent Status Your boiler is currently operating normally and successfully heating your radiators. LED5 Permanent Status Your boiler is receiving electrical power and is currently in its normal standby state, ready to provide heating and hot water.