Ferroli Tempra 12 18 Fault codes & diagnostics

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

Regular Natural Gas 12-18 kW Discontinued
GC Numbers 41-267-1141-267-12
Download the Ferroli Tempra 12 18 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 →

Just want the most common Ferroli Tempra 12 18 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 4 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 to operate safely.

High DIY-safe £0-£80

What to check first

  1. Locate the external filling loop, which is usually a flexible silver braided hose with one or two small valves underneath the boiler.
  2. Open the valves slowly to allow mains water into the system while watching the pressure gauge on the front panel.
  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 gauge
  • Pressure relief valve
Full explanation for 5 (Flashing Light)
Digital codes
F1

Your boiler is unable to light its internal flame, which means you currently have no heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Detection probe

Related codes

Full explanation for F1
lockout light

Your boiler has stopped working as a safety precaution and needs a manual reset to try and start up again.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • PCB
  • Gas valve
Full explanation for lockout light
Red lockout light

Your boiler has stopped working as a safety precaution and needs you to manually restart it to try and clear the error.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Gas valve
  • Printed circuit board
Full explanation for Red lockout light
Status & diagnostic codes

3 operating states & engineer diagnostics

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

4 (Flashing Light) Status Your boiler is currently in standby mode and is working exactly as it should while waiting for a signal from your thermostat to provide heating. 4 (Permanent Light) Status Your boiler is currently operating normally and is actively heating your radiators. 5 (Permanent Light) Status Your boiler is correctly receiving electrical power and is currently in its standard standby or operating mode.