Common problems guide

The most common Saunier Duval Opalia problems

The faults most likely to send a Saunier Duval Opalia 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.

The 3 most common faults

01

Fault finding (Page 9 - 10) High Engineer

The boiler documentation is incomplete and does not define the specific fault code, so the system remains in an unknown error state.

Est. cost: £120-250
Parts: Printed Circuit Board, Ignition Electrode, Gas Valve

Full guide for Fault finding (Page 9 - 10)

02

Safety disconnection (General) High Engineer

Your water heater has detected a safety issue and stopped working as a precaution because it cannot get the gas supply it needs to start.

Est. cost: £100-250
Parts: Gas valve, Ignition lead, Flame sensor

Full guide for Safety disconnection (General)

03

Safety indicator (4) lights Emergency Engineer

Your boiler has detected a safety issue and has shut itself down to prevent any potential danger.

Est. cost: £120-300
Parts: Flame rectification probe, Gas valve, Ignition lead

Full guide for Safety indicator (4) lights

Parts most often replaced

on the Saunier Duval Opalia

Printed Circuit BoardIgnition ElectrodeGas ValveGas valveIgnition leadFlame sensor

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 Saunier Duval 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 3-code list for the Saunier Duval Opalia