Ferroli Boiler Error Codes: Common Faults & Reset Procedures

Quick Answer: Ferroli boilers (Modena, Domina, DOMIproject, Sigma) display fault codes as numbers or alphanumeric codes depending on the model generation. The most common faults are A01 (ignition failure), A03 (flame loss), A04/F04 (low water pressure), and F05 (overheat). Reset procedure: press and hold the reset button for 2–3 seconds. Ferroli are an Italian manufacturer with UK distribution; some older model parts are harder to source than UK-manufactured alternatives.

Summary

Ferroli is an Italian heating and refrigeration manufacturer with a significant UK market presence, particularly in the combi boiler sector. The Modena series (Modena HE, Modena F24, Modena F28, Modena F32) has been one of the most widely installed combis in UK social housing and new-build developments over the past 20 years. The DOMIproject and DOMIcompact ranges represent their more recent UK offering.

Ferroli fault codes are displayed on the LCD display on modern models (post-2010) or as LED flash sequences on older models. The fault code numbering varies across the Ferroli range — the Modena, DOMIproject, and Sigma ranges use different code conventions, so always verify against the model-specific installation manual. This is particularly important with Ferroli, as generic boiler fault code tables are sometimes inaccurate for specific Ferroli models.

A known issue with the Ferroli Modena HE range is the PCB (printed circuit board) failure rate — the PCBs on older Modena units are no longer manufactured and the cost of a replacement (if available) often exceeds the boiler's remaining useful value. Engineers attending Ferroli boilers should flag this potential uneconomical repair scenario to the customer before ordering parts.

Key Facts

• Italian manufacturer — UK distribution via Ferroli UK; technical helpline available for Gas Safe engineers
• Modena HE — the most common UK Ferroli combi; widely used in social housing and housing association stock
• DOMIproject — Ferroli's current UK combi range; more recent models with better parts availability
• PCB availability — older Modena HE PCBs have limited availability; check before quoting a repair
• Reset procedure — press and hold reset button 2–3 seconds (varies by model — see below)
• A-codes — lockout faults on modern Ferroli models; require manual reset
• F-codes — some models use F for faults; the distinction between A and F depends on the model
• Condensate drainage — Ferroli condensing models produce significant condensate; condensate trap blockage is a very common cause of A01 and pressure switch faults
• Gas valve type — Ferroli uses Sit and Honeywell gas valves depending on model and year; confirmed by engineer with Gas Safe registration
• Expansion vessel — located inside the boiler casing; access requires front panel removal; test with system depressurised

Fault Code Reference Table (Modena / DOMIproject)

Older Modena LED Flash Codes

Detailed Guidance

Reset Procedure by Model

Modena HE (LCD display models):

1. The fault code is shown in the LCD display window.
2. Press the reset button (marked with an arrow pointing right or a flame symbol) on the right side of the programmer panel.
3. Hold for 2–3 seconds until the display clears and the boiler attempts ignition.

DOMIproject and DOMIcompact:

1. The fault code displays on the digital screen.
2. On DOMIproject: the reset function is accessed by pressing the "R" key or the mode selection key held for 3 seconds. Consult the quick reference inside the facia panel.

Older Modena (LED only):

1. Count the LED flashes (allow a 3-second gap between sequences).
2. Reset: press and hold the reset push-button inside the front flap for 2–3 seconds; or switch off at the isolator and back on.

Important: Never press reset more than 2–3 times in succession. Repeated attempts to restart a boiler with an active fault can flood the heat exchanger with unburned gas, creating a hazard when ignition eventually occurs.

A01 — Ignition Failure on Ferroli

Ferroli A01 ignition failure shares causes with most other combi boilers, but Ferroli boilers have some specific points:

FERROLI A01 IGNITION FAILURE
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Check gas supply (other appliances working)
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Winter check: frozen condensate pipe
- Ferroli condensate outlets are typically at the rear or base
- External white 22mm plastic pipe is vulnerable in cold weather
- Thaw with warm water; do NOT use boiling water
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Engineer access:
Check condensate trap inside boiler (reachable without isolation on some
Modena models; check the service manual for your specific model)
- Condensate trap can block with algae or debris
- Remove and clean: pour hot water through; use small brush
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Inspect ignition and ionisation electrodes:
- Ferroli Modena: electrodes are at the burner, accessed from the front
- Electrode to burner gap: typically 3–4mm
- Clean contamination with fine emery cloth
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Gas Safe engineer:
- Check gas inlet pressure (20 mbar minimum for natural gas)
- Check gas valve operation: does valve open on demand?
- Combustion analysis to confirm CO/CO₂ levels

A04/F04 — Low Pressure

Ferroli pressure faults follow the same pattern as other sealed system boilers:

1. Locate the pressure gauge — on Modena HE, the gauge is visible through the glass panel in the facia.
2. If below 1 bar, top up via the filling loop.
3. Filling loop location on Ferroli Modena: typically at the base of the boiler; the loop has two blue-handled valves.
4. Open valves until pressure reaches 1.0–1.5 bar; close both valves.
5. Reset the boiler.

For repeated pressure loss, the expansion vessel in Ferroli Modena is located internally. To test:

1. Drain system to 0 bar.
2. Locate the Schrader valve on the expansion vessel (access via lower front panel).
3. Press the Schrader core — if water comes out, the vessel is waterlogged and needs replacement.

F05 / A05 — Overheat

Ferroli overheat faults have the same causes as any sealed system combi:

• Pump failure (most common)
• All TRVs closed (particularly likely if the boiler room or hallway has a TRV set to minimum)
• Magnetite sludge blocking the primary heat exchanger

Check pump operation: the pump on Modena HE is accessible from the front after removing the casing. On newer DOMIproject models the pump is visible when the front panel is open. A non-running pump body (cold, silent) indicates pump failure.

Ferroli Modena HE PCB Failure — Important Note for Engineers

The Ferroli Modena HE range was widely installed between 2000 and 2012. Many units are now 12–20 years old. The PCBs (printed circuit boards, part numbers vary by generation) are no longer in primary manufacture and NOS (new old stock) PCBs may be available through specialist electrical refurbishers but at significant cost.

Before diagnosing PCB failure on a Modena HE, ensure all other components have been tested — in particular:

• Thermistors (a failed thermistor mimics a PCB fault)
• Earth fault (a poor earth can cause spurious PCB codes on some models)
• Low voltage supply to the PCB (check the boiler is receiving stable 230V)

If PCB replacement is confirmed necessary, assess the repair cost against replacement boiler cost. A PCB for an older Modena HE may cost £150–£300 plus labour on top of a unit that is 15+ years old and no longer carries warranty.

Frequently Asked Questions

Is Ferroli a reliable boiler brand?

Ferroli occupies the budget-to-mid range of the UK market. Their newer DOMIproject range has improved significantly over the older Modena HE. The Modena HE had known issues with PCB reliability. In general, annual servicing by a Gas Safe engineer extends the life of any boiler significantly.

Parts for my Ferroli Modena are hard to find — what do I do?

Try Ferroli UK directly (www.ferroli.co.uk), Gas Parts (a UK trade distributor), or IHVAC parts. Some Ferroli parts are cross-referenced to Italian originals (Sit gas valves, SIT electrodes) which may be more readily available. If the specific PCB is no longer available, replacement of the boiler is likely the most cost-effective option.

How do I know if my Ferroli is a condensing model?

Any Ferroli boiler with a white plastic pipe at the base or rear (the condensate pipe to the drain) is a condensing model. All Ferroli boilers manufactured since approximately 2005 are condensing. Non-condensing Ferroli models (identified by no condensate pipe) will be at least 20 years old.

My Ferroli shows F36 (flame present without demand) — is this dangerous?

F36 (ghost flame) indicates the PCB is detecting a flame signal when the boiler has not demanded ignition. This suggests either a gas valve that is not fully closing (allowing a small gas flow that is igniting) or a contaminated ionisation electrode that is generating a false flame signal. A Gas Safe engineer should attend immediately — a leaking gas valve can allow gas to accumulate in the boiler case. Do not restart the boiler — contact a Gas Safe engineer.

Regulations & Standards

• Gas Safe Register — mandatory for all gas work

• BS EN 677:1998 — condensing boilers standard

• Building Regulations Part J — combustion appliances; flue and condensate requirements

• Ferroli UK: Technical documentation — model manuals and fault code lists

• Gas Safe Register — engineer search

• HHIC: Boiler guidance — industry boiler maintenance guidance

• vaillant — Vaillant F-code guide

• ideal — Ideal error codes

• boiler losing pressure — pressure fault detailed diagnosis

• powerflush — overheat fault root cause treatment