Ferroli Atlas D Fault codes & diagnostics

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

Regular Oil 30-110 kW Discontinued

Replaced by: Atlas Condensing

Download the Ferroli Atlas D manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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7 High 2 Low

All 9 documented codes

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A03

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

High Engineer only £120-250

Parts commonly replaced

  • Central heating sensor
  • Circulation pump
  • Primary heat exchanger

Related codes

F10

Your boiler has lost the ability to accurately measure the temperature of the water being sent to your radiators, so it has shut down to prevent overheating.

High Engineer only £120-220

Parts commonly replaced

  • Delivery temperature sensor
  • Wiring harness / sensor connection

Related codes

F34

Your boiler has detected that the electricity supply reaching it is too low to operate safely, causing it to shut down to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • External power supply/fused spur
  • PCB (Printed Circuit Board)

Related codes

F35

Your boiler is struggling because the electricity supply it is receiving from your home is unstable or not at the correct frequency.

High Engineer only £120-250

Parts commonly replaced

  • Control board (PCB)
  • Wiring harness

Related codes

F37

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

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is a silver braided flexible hose connected between two pipes under your boiler.
  2. Open the small black or blue valves on either end of the hose to allow mains water to enter the system.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (usually between 1.0 and 1.5 bar), then tightly close both valves.

Parts commonly replaced

  • Pressure relief valve
  • Expansion vessel
  • Pressure sensor

Related codes

F39

Your boiler is struggling to read the temperature outside, so it is currently operating using standard internal settings instead of adjusting itself based on the weather.

Low Engineer only £120-200

Parts commonly replaced

  • External temperature sensor
  • Wiring loom

Related codes

F40

Your boiler has detected that the water pressure level inside your heating system is currently too high or too low for it to operate safely.

High DIY-safe £80-150

What to check first

  1. Check the system pressure gauge on the front of the boiler.
  2. If the pressure is below 1 bar, locate the filling loop to top up water until the needle reaches 1.5 bar.
  3. If the pressure is above 2.5 bar, bleed a radiator elsewhere in your home to release excess pressure.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Expansion vessel

Related codes

F47

Your boiler's sensor is failing to detect the water pressure, so it has shut down to prevent damage to the system.

High Engineer only £150-250

Parts commonly replaced

  • Pressure sensor
  • Pressure transducer

Related codes

FH

Your boiler is currently running a two-minute air-clearing routine to remove trapped air from the system before it attempts to light.

Low DIY-safe

What to check first

  1. Wait for the 120-second countdown to complete automatically.
  2. Do not interrupt the boiler while the cycle is running.
  3. If the boiler does not start after 2 minutes, simply reset the unit using the reset button.