- Boilers
- Gas boiler
E.04.12
Baxi E.04.12 on a gas boiler: false flame detection fault
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Baxi E.04.12 means an ignition fault on the Neodens Lite caused by false flame detection: the boiler senses a flame when there should be none. Baxi points to the earth, the supply voltage or the electrodes. Reset once and, if it returns, call a technician.
Safety first
Stop and check this first
- If you smell gas, do not reset: do not light flames or use switches, shut off the gas, open windows, leave the home and call your gas distributor's emergency number and a qualified professional from outside, as Baxi instructs.
- If you smell combustion fumes, Baxi says to switch the boiler off, open windows, leave and call a professional. Headache, dizziness or nausea can mean carbon monoxide. Baxi recommends smoke and CO alarms in the home.
- Do not touch plugs, cables or the boiler terminal block to test the earth: earth and voltage checks are technician work.
Safe checks you can perform
- Smell of gas or fumes near the boiler
- When E.04.12 appeared
- Single reset with the RESET key
- Earth, voltage and electrodes by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Earth and polarity check
- Do not attempt this professional task: Supply voltage measurement
- Do not attempt this professional task: Electrode check
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Earth and polarity check
What they doThe technician measures the continuity of the boiler earth circuit and checks that live and neutral are on the right terminals.
They must show youthe tester reading.
In writingthe measured value and whether the connection was corrected.
Supply voltage measurement
What they doThey measure the voltage at the boiler supply and check that it is stable.
They must show youthe multimeter reading.
In writingthe voltage measured and any advice on the electrical installation.
Electrode check
What they doWith the power off and the gas closed, they check the cleanliness, position and insulation of the electrodes and replace them if damaged.
They must show youthe removed electrode or its condition, with a photo.
In writingwhether it was cleaned, repositioned or replaced.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Smell of gas or fumes near the boiler
- Who:
- you.
- How:
- go near without turning on lights or using switches and notice whether there is a smell of gas or combustion fumes.
- Result that matters:
- whether there is a smell or not.
- If you smell gas:
- do not reset and follow the gas warning on this page.
- If there is no smell:
- move on to noting when the code appeared.
- Evidence to keep:
- the time and what you noticed.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
When E.04.12 appeared
- Who:
- you.
- How:
- note whether it coincided with a storm, a power cut or flicker, electrical work in the home or a powerful appliance plugged in near the boiler.
- Result that matters:
- whether there are clues pointing to voltage or earth.
- If it matches something electrical:
- tell the technician; Baxi lists earth and voltage.
- If it matches nothing:
- note the time and move on to the reset.
- Evidence to keep:
- date, time and what was happening in the home.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
Single reset with the RESET key
- Who:
- you.
- How:
- with no smell of gas, press the manual reset (RESET) key for 1 second, as Baxi says for E faults. Once only.
- Result that matters:
- whether the boiler lights and E.04.12 does not return.
- If it works:
- note the date and watch whether it repeats.
- If it returns:
- do not insist and call the technician.
- Evidence to keep:
- photo of the display and the result.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
Earth, voltage and electrodes by the technician
- Who:
- qualified gas technician.
- How:
- measures earth continuity and polarity, checks the supply voltage and inspects the condition and insulation of the electrodes.
- Result that matters:
- which of the three Baxi causes is present.
- If earth or voltage is at fault:
- the electrical installation is corrected.
- If an electrode is at fault:
- it is cleaned, repositioned or replaced.
- Evidence to keep:
- measured values and part replaced.
Measuring earth and voltage and checking electrodes means opening the boiler and working with mains power. Baxi says to disconnect the power and close the gas before working on it.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Boilers
- Brand
- Baxi
- Product type
- Gas boiler
Known code variants
- Baxi E.04.12
- E 04 12
- E.04 .12
- E04.12
- E0412
- Neodens Lite E.04.12
What it means
On the Baxi Neodens Lite, E.04.12 is a permanent fault: ignition failure due to false flame detection. The board receives a flame signal at a moment when there should be none and blocks ignition for safety. Baxi gives three checks: the earth circuit, the supply voltage and the condition of the electrodes. Like all E faults, it stops the boiler and needs a reset with the RESET key for 1 second; if it keeps happening, a qualified technician must be called.
Warnings and stop conditions
- Criticalsource verified
If you smell gas, do not reset: do not light flames or use switches, shut off the gas, open windows, leave the home and call your gas distributor's emergency number and a qualified professional from outside, as Baxi instructs.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
- Criticalsource verified
If you smell combustion fumes, Baxi says to switch the boiler off, open windows, leave and call a professional. Headache, dizziness or nausea can mean carbon monoxide. Baxi recommends smoke and CO alarms in the home.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
- Mediumeditorial warning
Do not touch plugs, cables or the boiler terminal block to test the earth: earth and voltage checks are technician work.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
Symptoms and causes
Probable causes · in order
- Faulty earth connectionCommon
Baxi says to check the earth circuit first. A poor earth or reversed polarity can create a false flame signal at the electrode.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
- Incorrect supply voltagePossible
Baxi lists the supply voltage. It fits if the fault coincides with storms, power cuts or powerful appliances on the same circuit.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
- Electrodes in poor conditionPossible
A dirty, damp, bent electrode or one with damaged insulation can give a signal without a flame. Baxi says to check the condition of the electrodes.
Evidence: Baxi Neodens Lite 24 AF, 24/24 F y 28/28 F, manual de usuario, instalación y mantenimiento 7892434
Virtual technician
Does E.04.12 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
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