Common problems guide

The most common Ariston Genus 24 RFFI problems

The faults most likely to send a Ariston Genus 24 RFFI 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.
3 documented codes
3 most common
3 DIY-safe checks
0 engineer needed

The 3 most common faults

01
(B) LED turning on High DIY-safe

Your boiler has tried to ignite to provide heat but failed to detect a flame, causing the system to shut down for safety.

What to try first

Check that your gas emergency control valve is in the 'on' positionCheck if other gas appliances in your home, such as a hob, are working correctlyPress the 'R' or Reset button on the control panel to attempt a restart

Est. cost
£100-280
Parts
Ignition Electrode, Flame Sensing Probe, Gas Valve
Full guide for (B) LED turning on
02
(G) LED turning on High DIY-safe

Your boiler has switched itself off because it reached an unsafe temperature to prevent damage to the internal components.

What to try first

Check that all radiator valves are fully open to allow water to circulate.Ensure your system pressure is topped up to between 1 and 1.5 bar.Wait 15 minutes for the system to cool down and gently press the reset button.

Est. cost
£120-£350
Parts
Circulating Pump, Overheat Thermostat, Diverter Valve
Full guide for (G) LED turning on
03
(D) LED turning on High DIY-safe

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

What to try first

Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the small valve(s) on the loop to allow water into the system.Watch the pressure gauge until it reaches 1.5 bar, then close the valves tightly.

Est. cost
£0-120
Parts
Filling loop, Expansion vessel, Pressure relief valve
Full guide for (D) LED turning on

on the Ariston Genus 24 RFFI

Ignition ElectrodeFlame Sensing ProbeGas ValveCirculating PumpOverheat ThermostatDiverter Valve

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 Ariston 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 Ariston Genus 24 RFFI