Ariston Genus 27 BFFI Plus Fault codes & diagnostics

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

Combi Natural Gas
GC Number 47-116-11
Download the Ariston Genus 27 BFFI Plus manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
5 High 1 Medium
Fault codes

All 6 documented codes

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7

Your boiler is shutting down repeatedly because it is overheating, which is usually caused by trapped air inside the system or a faulty temperature sensor.

High Engineer only £120-£250

Parts commonly replaced

  • Safety thermostat
  • NTC temperature sensor

Related codes

Full explanation for 7
8

Your boiler is struggling to heat your radiators properly because it is having trouble measuring or regulating the water temperature.

Medium Engineer only £100-200

Parts commonly replaced

  • Central heating NTC temperature sensor
  • Automatic bypass valve

Related codes

Full explanation for 8
A01

Your boiler has stopped working because it tried to light three times but could not detect a flame.

High DIY-safe £100-£350

What to check first

  1. Check if other gas appliances in your home (like a hob) are working to ensure your gas supply is on.
  2. If you have a prepaid meter, check that you have remaining credit.
  3. Press the 'Reset' button on the boiler control panel once to see if the system restarts.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame sensing electrode
  • Printed Circuit Board (PCB)

Related codes

Full explanation for A01
A02

Your boiler has stopped working because the water pressure is too low, meaning there isn't enough water inside the system to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver braided hose with small taps) underneath the boiler.
  2. Slowly open the taps until you hear the water flowing and watch the pressure gauge needle move.
  3. Close the taps firmly once the pressure gauge reaches between 1 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for A02
A03

Your boiler has shut down because it has detected that the water inside has become dangerously hot and is potentially overheating.

High Engineer only £150-£350

Parts commonly replaced

  • Circulation Pump
  • NTC Temperature Sensor
  • Main Heat Exchanger
Full explanation for A03
A07

Your boiler has tried to light several times during its cycle but the flame keeps going out, causing the system to lock itself for safety.

High Engineer only £120-350

Parts commonly replaced

  • Ionisation probe
  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for A07
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