Common problems guide

The most common Ferroli Tempra 12 18 problems

The faults most likely to send a Ferroli Tempra 12 18 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
4 documented codes
4 most common
1 DIY-safe checks
3 engineer needed

The 4 most common faults

01
5 (Flashing Light) High DIY-safe

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

What to try first

Locate the external filling loop, which is usually a flexible silver braided hose with one or two small valves underneath the boiler.Open the valves slowly to allow mains water into the system while watching the pressure gauge on the front panel.Close the valves tightly once the needle reaches the green zone, typically between 1.0 and 1.5 bar.

Est. cost
£0-£80
Parts
Filling loop, Pressure gauge, Pressure relief valve
Full guide for 5 (Flashing Light)
02
F1 High Engineer

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

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, Detection probe
Full guide for F1
03
lockout light High Engineer

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

Est. cost
£120-250
Parts
Ignition electrode, Flame rectification probe, PCB
Full guide for lockout light
04
Red lockout light High Engineer

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

Est. cost
£120-250
Parts
Ignition electrode, Flame rectification probe, Gas valve
Full guide for Red lockout light
Parts most often replaced

on the Ferroli Tempra 12 18

Filling loopPressure gaugePressure relief valveIgnition electrodeGas valveDetection probe

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Ferroli shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 4-code list for the Ferroli Tempra 12 18

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →