Ferroli Domina 102 Fault codes & diagnostics

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

Combi Natural Gas 24 kW 2000-2005 Discontinued
GC Number 47-267-23

Replaced by: Domina F 24 E

Download the Ferroli Domina 102 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.
13 High 1 Medium 2 Low

All 16 documented codes

Tap any card for details

5 (Flashing)

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

High DIY-safe £80-120

What to check first

  1. Locate the external filling loop, which is usually a braided silver hose connecting two pipes under the boiler
  2. Open the small valve or tap on the filling loop to allow cold mains water to enter the system
  3. Watch the pressure gauge on the front of the boiler and close the valve once the needle reaches 1.5 bar
  4. Check for any obvious puddles under radiators or the boiler that might explain the initial pressure loss

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge
LED 5 (Flashing light)

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

High DIY-safe £0-90

What to check first

  1. Locate the external filling loop (a flexible silver hose connecting two pipes near the boiler).
  2. Slowly open the tap or valve on the filling loop to allow water into the system.
  3. Watch the pressure gauge on the boiler until the needle reaches the green zone (usually 1.0 to 1.5 bar), then close the valve tightly.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge
LED5 bar (Flashing)

Your boiler has stopped heating because the water pressure inside the system has dropped too low to operate safely.

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is a silver braided hose connected between two valves underneath the boiler.
  2. Open the valves slowly to allow mains cold water into the system while watching the pressure gauge.
  3. Close the valves tightly once the needle reaches the green zone, typically between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge
E03

Your boiler has stopped working because it cannot safely clear its exhaust gases, preventing it from lighting to keep your home safe.

High Engineer only £120-250

Parts commonly replaced

  • Air pressure switch
  • Flue fan assembly
  • Venture pipe
E05

Your boiler is struggling to accurately measure the temperature of the water being sent to your radiators, so it has turned itself off to avoid overheating.

High Engineer only £120-220

Parts commonly replaced

  • Central heating temperature sensor (NTC)
  • Wiring harness

Related codes

E06

Your boiler is currently unable to detect the temperature of the water coming from your taps, which means it has stopped providing hot water to prevent overheating.

High Engineer only £120-200

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC temperature sensor

Related codes

Heating demand light ON

Your boiler is struggling to register that you have turned the heating on, causing it to stay idle or fail to start.

Medium Engineer only £120-200

Parts commonly replaced

  • Central Heating NTC Sensor
Insufficient pressure

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

High DIY-safe £80-120

What to check first

  1. Locate the external filling loop, which is a silver braided flexible hose connected between two pipes underneath the boiler.
  2. Open the small valve(s) on either end of the hose to allow mains water into the system until the pressure gauge reads between 1 and 1.5 bar.
  3. Firmly close the valve(s) to stop the water flow and ensure the boiler resets itself.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge
LED 5

Your boiler has detected that there is not enough water inside the system to operate safely, so it has turned itself off to prevent damage.

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is usually a silver flexible hose with one or two small valves under the boiler.
  2. Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front of the boiler.
  3. Close the valve(s) tightly once the needle reaches the green zone, typically between 1 and 1.5 bar.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
LED2

Your boiler is attempting to start but failing to ignite, causing it to lock itself down for safety reasons.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Low water pressure light ON

Your boiler has stopped working because the water pressure inside the system is too low to operate safely.

High DIY-safe £80-150

What to check first

  1. Locate the filling loop, which is a silver braided hose with one or two valves underneath the boiler.
  2. Slowly open the valve(s) to let water into the system while watching the pressure gauge on the front of the boiler.
  3. Close the valve(s) firmly once the needle sits between 1 and 1.5 bar, then check for any leaks.

Parts commonly replaced

  • Pressure relief valve
  • Pressure gauge
  • Water pressure switch
Red LED Out (Lockout)

Your boiler has stopped working for safety reasons and is refusing to ignite, which means it currently cannot provide any heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Gas valve
  • Ignition electrode
Red lockout light

Your boiler has detected a problem and safely shut itself down to prevent damage, meaning you currently have no heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe
  • PCB
Tap symbol light ON

Your boiler is struggling to detect the temperature of your hot water, which likely means you have no hot water working at your taps.

High Engineer only £120-180

Parts commonly replaced

  • DHW NTC sensor

12 operating states & engineer diagnostics

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

4 (Flashing) Status Your boiler is currently in standby mode and is simply waiting for a signal from your thermostat or hot water tap to start heating. LED 4 (Flashing light) Status Your boiler is currently in standby mode and is working correctly, meaning it is simply waiting for a signal from your thermostat to start heating your home. 4 (Permanent Light) Status Your boiler is currently operating normally as it is in the process of heating your radiators. 5 (Permanent Light) Status Your boiler is operating normally and is simply indicating that it is receiving electrical power. 45 Diagnostic Your boiler is flagging an incorrect configuration setting related to the internal gas burner setup, which prevents it from igniting safely. 47 Diagnostic Your boiler has detected an issue with the water pressure sensor, which is preventing it from firing up correctly. 50 Diagnostic Your boiler is signalling an issue with the air intake or exhaust system, which prevents it from operating safely. LED 4 (Permanent light) Status Your boiler is currently operating normally and is actively heating your radiators. LED 5 (Permanent light) Status Your boiler is not receiving the electrical power it needs to turn on, which is usually caused by a tripped switch or a power supply issue. LED1 Status Your boiler is failing to detect a stable power supply, which is preventing it from starting up or operating correctly. LED4 (Permanent) Status Your boiler is currently running the central heating mode and the light is simply telling you that the system is active. LED5 (Permanent) Status Your boiler is confirming that it has a stable electrical power supply and is ready to operate under normal conditions.