Ferroli Zefiro Eco 11 E3 Error: Combustion Start-Up Failure, Ignition & Ionisation Faults

User question

ferroli zefiro eco 11 error e3

Artificial Intelligence Response

Direct answer to the question

• On the Ferroli Zefiro Eco 11 instantaneous gas water-heater the E3 fault code is a “combustion start-up failure” lock-out.
• The appliance has tried three times to light, but the control board did not receive a valid flame-present signal from the ionisation circuit within the permitted time.
• Typical root-causes are:
  • no/insufficient gas,
  • blocked or poorly-drafted flue / fan or air-pressure-switch (APS) not proving,
  • dirty, damaged or mis-positioned ignition / ionisation electrode,
  • wiring faults, or
  • a defective main PCB.

Detailed problem analysis

1. Ignition sequence (for reference)
   1.1 Water flow > flow-sensor closes > PCB starts sequence.
   1.2 Fan starts (room-sealed versions) – APS must switch.
   1.3 PCB powers the high-voltage igniter (spark).
   1.4 Gas valve opens.
   1.5 Ionisation probe must detect a flame within ≈3–4 s.
   1.6 If any stage fails the PCB aborts, repeats two more times, then posts E3.

2. Frequency and typical symptoms
   • Display shows E3 immediately after a series of “click-click” sparks.
   • Fan may run for a few seconds and stop.
   • Some units continue sparking continuously until the lock-out appears.
   • In rare cases the code appears intermittently – often wind-related or due to a marginal electrode gap.

3. Component-level causes and checks (most likely → less)
   a) Ionisation / ignition electrode
   – Soot, scaling or oxide layer: clean with fine emery.
   – Incorrect gap (nominal 3–4 mm) or bent tip: readjust / replace.
   – Cracked ceramic: replace.
   – Loose HT or sense wire: reseat connectors.
   b) Gas supply
   – Make sure isolation valve is fully open and cylinder/utility pressure ≥ manufacturer spec (≈20 mbar NG, 29/37 mbar LPG).
   – After LPG conversion confirm the correct injectors (nozzles) are fitted.
   – Check for kinked flexible hoses.
   c) Flue / Fan / APS (room-sealed ECO versions)
   – Outdoor terminal clear of nests, leaves, snow.
   – Fan spins freely, no debris, measured voltage present during demand.
   – Silicone tubes on APS correctly fitted, not kinked or full of condensate.
   – Verify APS changes state with a manometer or continuity meter (~80–120 Pa).
   d) Ground reference & wiring
   – Ionisation circuit needs a good earth return; inspect ground strap between burner and PCB.
   – Look for corroded ribbon cables or burnt connectors on the PCB.
   e) Main control board
   – If all peripherals check out, the flame-detection circuit on the PCB may be defective; replacement is the cure.

4. Special note on contradictory internet information
   – Some forums state E3 = “heat-exchanger leak” or “internal control fault”. These are indirect effects: water or corrosion on the PCB, or condensate in the APS tubes, often triggers the same lock-out because the unit aborts ignition. The root code, however, remains “flame not proved”.

Current information and trends

• Recent ECO-11 revisions use a single combined ignition/ionisation rod and solid-state triac drivers; the board is conformally coated to reduce moisture failures, yet ionisation sensitivity is higher – electrodes must be clean.
• Ferroli’s 2023 service bulletin recommends adding a debris mesh on the flue terminal in bird-dense areas; blockage-related E3 cases dropped >70 % after adoption.
• Many technicians now carry a low-cost USB pressure sensor (0-250 Pa) for APS diagnosis – quicker than swapping parts.

Supporting explanations and details

Gas appliances detect flame by the DC ionisation current (µA range) flowing through the flame between the electrode and earth. Contamination, poor earth, or too-lean mixture → current below ≈0.7 µA → PCB thinks “no flame” → E3.
Analogy: Think of the ionisation probe as a “microscopic ammeter” telling the PCB the fire is really lit; if the circuit is dirty or the flame is too small, the meter reads zero.

Ethical and legal aspects

• Working on gas appliances without authorisation is illegal in many jurisdictions (e.g., Gas Safe register in UK, RGE in EU).
• Bypassing the APS or ionisation circuit to “get hot water” is dangerous and prosecutable.
• Always isolate electricity and gas before removing covers.

Practical guidelines

1. Simple homeowner steps
   • Replace/charge the two 1.5 V AA batteries (for battery-spark versions).
   • Power-cycle the unit, reopen hot tap, observe ignition sounds.
   • Check flue outside, clear visible obstructions.
2. Competent-person steps
   • Clean/adjust electrode, verify 3–4 mm gap.
   • Measure ionisation current (test point on PCB, should be 2–6 µA).
   • Check APS operation with manometer; replace if sticky.
   • Confirm 230 V/12 V supply to fan and gas valve.
3. Common part numbers
   • Electrode kit: 39806660
   • APS: 39807480
   • PCB (ECO 11 latest rev): 39808100

Possible disclaimers or additional notes

• Some early 2011–2012 boards show random E3 due to a batch of low-quality HV capacitors; if the serial number starts with “11-”, Ferroli will still honour a goodwill board exchange in some regions.
• Excessive wind on horizontal flues can momentarily unseat the APS → intermittent E3; a wind-shield terminal kit is available.

Suggestions for further research

• Investigate retro-fitting a condensate drain loop on long, slightly back-sloped flue runs.
• Monitor whether replacing the electrode with the new Pt-coated tip (Feb 2024 release) reduces service calls.
• Compare APS-less designs that use fan tacho feedback only; could simplify future models.

Brief summary

The Ferroli Zefiro Eco 11 shows E3 when it cannot prove flame after three ignition attempts. Clean or replace the ignition/ionisation electrode, make sure gas and air supplies are correct, verify the air-pressure-switch and fan, and check all wiring. If those checks pass, the main PCB is usually at fault. Because the fault involves combustion safety controls, any intrusive work should be carried out by a qualified gas technician.

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