Ferroli i29 Fault codes & diagnostics

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

Combi Natural Gas 28 kW 2017 onwards
GC Number 47-267-65
Download the Ferroli i29 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.
1 Emergency 17 High
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
47-267-65 i29 2017–present

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

Just want the most common Ferroli i29 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 18 documented codes

Tap any card for details

A01

Your boiler is failing to start because it cannot detect a flame, meaning you have no heating or hot water.

High DIY-safe £90-£350

What to check first

  1. Check if your gas supply is active by testing another gas appliance like a hob.
  2. Check for credit on your prepaid gas meter, if applicable.
  3. Press the Reset button on the boiler control panel once.
  4. Ensure the condensate drain pipe outside isn't frozen if the weather is extremely cold.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • PCB (Main Circuit Board)

Related codes

Full explanation for A01
A02

Your boiler thinks a flame is burning even when it’s supposed to be turned off, which causes it to shut down as a safety precaution.

High Engineer only £120-350

Parts commonly replaced

  • Ionisation Electrode
  • Flame Sensing Cable
  • Main PCB

Related codes

Full explanation for A02
A03

Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution to prevent damage.

High Engineer only £100-220

Parts commonly replaced

  • Heating temperature sensor (NTC)
  • Circulation pump
  • Overheated safety thermostat

Related codes

Full explanation for A03
A06

Your boiler is failing to keep a flame alight after starting up, which usually means it isn't getting enough gas or the flame isn't being detected correctly.

High Engineer only £120-280

Parts commonly replaced

  • Gas Valve
  • Ignition/Ionisation Electrode
  • PCB

Related codes

Full explanation for A06
A09

Your boiler has detected an issue with the component that controls the gas flow, meaning it cannot safely ignite to provide heating or hot water.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • PCB

Related codes

Full explanation for A09
A15

Your boiler is struggling to clear exhaust gases because it cannot confirm that the internal fan is moving air properly, so it has shut down for safety.

High Engineer only £150-250

Parts commonly replaced

  • Air pressure switch
  • Venturi
  • Fan assembly
  • Flue seals

Related codes

Full explanation for A15
A16

Your boiler has detected an issue with the valve that controls the gas supply, meaning it has safely shut down to prevent it from firing incorrectly.

Emergency Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • PCB

Related codes

Full explanation for A16
A23

Your boiler's computer has detected a configuration error and cannot operate correctly because it has lost its internal settings.

High Engineer only £150-300

Parts commonly replaced

  • Main control PCB
  • Wiring harness

Related codes

Full explanation for A23
A24

Your boiler's internal computer has lost its configuration settings and no longer knows how to operate correctly.

High Engineer only £120-350

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Configuration Key

Related codes

Full explanation for A24
F07

Your boiler has stopped working because it cannot safely confirm that waste gases are being cleared through the flue pipe.

High Engineer only £120-£260

Parts commonly replaced

  • Air Pressure Switch
  • Venting/Flue Baffle
  • Venturi Tube

Related codes

Full explanation for F07
F10

Your boiler has stopped working because it is unable to accurately measure the temperature of the water flowing out of it.

High Engineer only £120-220

Parts commonly replaced

  • NTC delivery sensor
  • Wiring harness

Related codes

Full explanation for F10
F11

Your boiler's temperature sensor has stopped sending the correct information to the control board, preventing the system from heating up safely.

High Engineer only £90-160

Parts commonly replaced

  • Flow temperature NTC sensor
  • Wiring harness

Related codes

Full explanation for F11
F34

Your boiler is receiving an insufficient amount of electricity to operate safely and has shut down to protect its internal electronics.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

Full explanation for F34
F35

Your boiler has detected that the electricity supply from your mains is too low for it to operate safely and has shut down to protect its components.

High Engineer only £100-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Voltage Regulator

Related codes

Full explanation for F35
F37

Your boiler has detected that the water pressure is too low for it to operate safely, which is usually fixed by topping up the system.

High DIY-safe £0-160

What to check first

  1. Locate the external filling loop (braided silver hose) usually found underneath the boiler.
  2. Slowly open the small valves at either end of the hose until you hear water flowing.
  3. Watch the pressure gauge and close the valves once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Water pressure switch
  • External filling loop

Related codes

Full explanation for F37
F43

Your boiler has stopped working because water is not moving through the system properly or there is too much air trapped inside.

High DIY-safe £100-£350

What to check first

  1. Check that the radiator valves are open
  2. Bleed all radiators to remove trapped air
  3. Check the boiler pressure gauge and top up to 1.5 bar if low
  4. Restart the boiler using the Reset button

Parts commonly replaced

  • Circulation pump
  • Automatic air vent
  • Main heat exchanger (if scaled)

Related codes

Full explanation for F43
F50

Your boiler's internal computer has developed an electrical fault and is unable to communicate with its sensors properly.

High Engineer only £280-450

Parts commonly replaced

  • DBM32B Main PCB
  • Earth connection wiring

Related codes

Full explanation for F50
F51

Your boiler's internal computer has developed a critical electronic fault and can no longer control the heating system safely.

High Engineer only £280-450

Parts commonly replaced

  • DBM32B Printed Circuit Board (PCB)
  • Earth connection wiring

Related codes

Full explanation for F51
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