Ferroli Force W Fault codes & diagnostics

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

System Natural Gas 60-150 kW 2019-present
Download the Ferroli Force W manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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Each cell = one fault code. Hover to identify.
4 Emergency 22 High 2 Low

All 28 documented codes

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37

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

High DIY-safe £80-150

What to check first

  1. Locate the filling loop, which is a silver braided hose or a small valve under the boiler.
  2. Slowly open the valve to let mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.
  3. Close the valve tightly and check your boiler to see if the error code has cleared.

Parts commonly replaced

  • Pressure relief valve
  • Filling loop
  • Pressure sensor

Related codes

A01

Your boiler is failing to light the flame needed to provide heating and hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe

Related codes

A02

Your boiler has detected a flame when it should be turned off, which triggers a safety shutdown to prevent gas buildup.

Emergency Engineer only £150-300

Parts commonly replaced

  • Ionisation electrode
  • Gas valve
  • Main PCB

Related codes

A03

Your boiler has detected that it is running too hot and has automatically shut down to prevent damage to the system.

High Engineer only £150-300

Parts commonly replaced

  • NTC sensor
  • Primary heat exchanger
  • Pump

Related codes

A04

Your boiler has detected an issue with its flue system, meaning it cannot safely vent exhaust gases, so it has shut down to protect your home.

Emergency Engineer only £150-350

Parts commonly replaced

  • Flue fan
  • Air pressure switch
  • Flue seals
  • Venturi

Related codes

A05

Your boiler has detected an issue with the internal ventilation system that removes exhaust gases, so it has safely shut down to prevent unsafe operation.

High Engineer only £150-350

Parts commonly replaced

  • Fan assembly
  • Air pressure switch
  • Wiring harness
  • PCB

Related codes

A06

Your boiler has tried to start several times but is unable to sustain a flame, so it has locked itself out for safety.

High Engineer only £150-350

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe

Related codes

A42

Your boiler has lost the ability to accurately measure the temperature of the water used for your heating, so it has shut down as a precaution to prevent overheating.

High Engineer only £120-200

Parts commonly replaced

  • Central heating flow sensor
  • Wiring harness

Related codes

A62

Your boiler has stopped working because the internal computer cannot talk to the part that controls the gas supply.

High Engineer only £150-300

Parts commonly replaced

  • Gas valve wiring harness
  • Gas valve unit
  • Main circuit board (PCB)

Related codes

A63

Your boiler's electronic command center is experiencing a serious internal error and cannot communicate with the system to start the heating process.

High Engineer only £250-450

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Control unit

Related codes

Showing 11–20 of 28
A64

Your boiler has detected an internal communication error and is unable to process its standard operating instructions, resulting in a system lockout.

High Engineer only £250-450

Parts commonly replaced

  • Main control board
  • Wiring harness

Related codes

F07

Your boiler has detected that the gases venting out of your flue are becoming dangerously hot, so it has shut down to prevent potential damage or fire risks.

Emergency Engineer only £150-350

Parts commonly replaced

  • Heat exchanger
  • Flue gas temperature sensor
  • Burner assembly

Related codes

F10

Your boiler has stopped working because it is unable to accurately read the temperature of the water being sent to your radiators, causing it to shut down to stay safe.

High Engineer only £120-200

Parts commonly replaced

  • Flow temperature sensor
  • Wiring harness

Related codes

F12

Your boiler is struggling to detect the temperature of the water for your taps and shower, which means you likely have no hot water.

High Engineer only £120-200

Parts commonly replaced

  • DHW NTC Sensor
  • Wiring harness

Related codes

F13

Your boiler has detected an issue with the sensor that monitors exhaust gases, so it has safely shut down to prevent any unsafe operation.

Emergency Engineer only £150-250

Parts commonly replaced

  • Flue gas sensor
  • Wiring harness
  • Control PCB

Related codes

F14

Your boiler has detected a communication issue with its temperature-sensing system, which has caused it to stop heating your home as a safety precaution.

High Engineer only £150-250

Parts commonly replaced

  • Delivery temperature sensor
  • Wiring harness
  • PCB

Related codes

F15

Your boiler has detected an issue with the internal ventilation system that removes exhaust gases, so it has automatically shut down for your safety.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

F26

Your boiler has detected an issue with the internal component that controls the gas supply, meaning it has safely shut itself down to prevent unsafe operation.

High Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • Main control board

Related codes

F34

Your boiler has detected that the electricity supply coming from your wall socket is too weak to operate the internal components safely.

High Engineer only £100-250

Parts commonly replaced

  • Control board
  • Power cable
  • Fuse

Related codes

F35

Your boiler has detected that the electricity supply coming from your home is unstable or not at the correct frequency, preventing it from operating safely.

High Engineer only £150-300

Parts commonly replaced

  • Main Control Board (PCB)
  • Wiring harness

Related codes

Showing 21–28 of 28
F37

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

High DIY-safe £80-150

What to check first

  1. Locate the filling loop (a flexible metal hose) underneath your boiler.
  2. Open the valves on the filling loop to allow cold mains water to enter the system.
  3. Watch the pressure gauge on the front of the boiler and close the valves once the needle reaches 1.5 bar.

Parts commonly replaced

  • Pressure relief valve
  • Pressure gauge
  • Expansion vessel

Related codes

F39

Your boiler is struggling to read the outdoor temperature, so it is choosing a default setting to keep your home warm while it waits for a fix.

Low Engineer only £120-200

Parts commonly replaced

  • External temperature sensor
  • Wiring loom

Related codes

F43

Your boiler has detected that the water inside the unit is not circulating or cooling down properly, so it has purposefully shut itself off to prevent the internal system from overheating.

High Engineer only £150-350

Parts commonly replaced

  • Circulation pump
  • Flow sensor
  • Heat exchanger

Related codes

F50

Your boiler is struggling to accurately measure the water temperature across its linked system, which is causing it to suspend its heating operations for safety.

High Engineer only £150-250

Parts commonly replaced

  • Cascade sensor
  • Wiring harness

Related codes

F52

Your boiler has stopped working because it cannot accurately detect the temperature of the water used for your radiators.

High Engineer only £120-200

Parts commonly replaced

  • Flow temperature sensor
  • Return temperature sensor
  • Wiring loom

Related codes

F66

Your boiler’s internal computer is experiencing a communication error, meaning the system cannot regulate itself and has shut down for safety.

High Engineer only £250-450

Parts commonly replaced

  • Control board
  • Wiring harness

Related codes

F99

Your boiler's electronic command center is currently unable to communicate with the display, meaning the system has safely shut down until the connection is restored.

High Engineer only £150-300

Parts commonly replaced

  • Control PCB
  • Display interface ribbon cable
  • Wiring harness

Related codes

FH

Your boiler is currently running a scheduled automatic process to remove trapped air from the system, which typically occurs after it has been switched on or reset.

Low DIY-safe

What to check first

  1. Wait for 5 minutes until the timer completes
  2. Do not turn off or reset the boiler during this process
  3. Observe if the display changes once the 300 seconds have passed

Related codes

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