Ariston Eurocombi 20 1mfs Fault codes & diagnostics

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

Combi Natural Gas 20 kW 1994-1996 Discontinued
GC Number 47-116-01

Replaced by: Eurocombi A/23 MFFI

Download the Ariston Eurocombi 20 1mfs 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 →

Just want the most common Ariston Eurocombi 20 1mfs faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 5 documented codes

Tap any card for details

Flame failure

Your boiler has failed to stay lit because it cannot detect a flame, causing the system to shut down for safety.

High DIY-safe £100-280

What to check first

  1. Check that your gas supply is turned on at the meter.
  2. Verify if other gas appliances in your home, like a hob, are working.
  3. Press the reset button on the control panel once to see if the boiler restarts.

Parts commonly replaced

  • Ionisation probe
  • Gas valve
  • Ignition electrode
Full explanation for Flame failure
Ignition Lockout

Your boiler has stopped working because it failed to light the flame properly, so it has shut itself down as a safety precaution.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Ignition transformer
Full explanation for Ignition Lockout
INSUFFICIENT WATER

Your boiler has detected that 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 filling loop, which is usually a silver braided hose with one or two valves located underneath the boiler.
  2. Gradually open the valve(s) to allow mains water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Close the valve(s) tightly to prevent over-pressurisation.

Parts commonly replaced

  • Filling loop
  • Pressure gauge
  • Pressure relief valve
Full explanation for INSUFFICIENT WATER
L.E.D. D

Your boiler is not detecting enough water inside the system to operate safely, so it has shut down to prevent internal damage.

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is usually a silver braided hose connecting two cold water pipes under the boiler.
  2. Open the valves on both ends of the hose to allow water to enter the system.
  3. Monitor the boiler's pressure gauge until it reads between 1.0 and 1.5 bar, then securely close both valves.

Parts commonly replaced

  • Pressure relief valve
  • Pressure switch
  • Circulation pump
Full explanation for L.E.D. D
Safety Shut-off

Your boiler has detected an internal electronic error and is preventing itself from igniting to ensure your safety.

High Engineer only £250-450

Parts commonly replaced

  • Printed Circuit Board (PCB)
Full explanation for Safety Shut-off
Status & diagnostic codes

1 operating states & engineer diagnostics

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

Limescale Build-up Diagnostic Your boiler has detected that built-up mineral deposits are preventing your water from heating efficiently, so it has capped the temperature to protect the system from further damage.