- Boilers
- Gas boiler
A02
Cointra A02 on a gas boiler: flame signal with burner off
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Cointra A02 means the boiler detects a flame signal while the burner is off. If there is no smell of gas or flue gases, press reset for one second, once; if A02 comes back, leave it and call an authorised technician.
Safety first
Stop and check this first
- If you smell gas, do not reset or press anything electrical: open windows, close the gas tap if it is within reach, leave the home and call your gas distributor's emergency number from the street. Cointra says to switch a faulty boiler off and have it repaired only by an authorised technician.
- Cointra warns of a risk of asphyxia from escaping flue gases if the boiler runs with the siphon empty. Headache, dizziness or nausea can mean carbon monoxide: switch the boiler off, ventilate, leave and get help. Keep a CO alarm nearby.
- Do not keep pressing reset: the Cointra table has its own lockout, A64, when the maximum number of consecutive resets is exceeded. If A02 returns, leave it locked out.
Safe checks you can perform
- Gas or flue gas smell near the boiler
- Condensate pipe in view
- A single reset with the reset key
- Electrode, wiring, siphon and board by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Flame status and fault history reading
- Do not attempt this professional task: Calibration and combustion after a replacement
- Do not attempt this professional task: Electrode and cable 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.
Flame status and fault history reading
What they doIn the Service menu, the technician reads the flame status in the Information menu and the last eight faults in the History menu.
They must show youthe history list on the display.
In writingthe codes read and their order.
Calibration and combustion after a replacement
What they doIf the electrode or board is replaced, the technician runs the 100 % calibration and measures CO2 at maximum and minimum output with an analyser.
They must show youthe analyser printout.
In writingthe measured values against the manufacturer's specification and the calibration done.
Electrode and cable check
What they doThe technician checks the electrode condition, that neither the electrode nor its cable is earthed, and the electrode gap after refitting, as Cointra describes.
They must show youthe removed electrode and the cable checked.
In writingwhat was found, whether it was cleaned or replaced and the part reference.
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.
Gas or flue gas smell near the boiler
- Who:
- you.
- How:
- walk up without pressing switches or turning lights on and notice whether there is a smell of gas or combustion fumes.
- Result that matters:
- whether there is a smell or not.
- If there is a smell:
- do not touch the boiler and follow the gas warning on this page.
- If there is no smell:
- go on to look at the condensate drain.
- Evidence to keep:
- the time and what you noticed.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Condensate pipe in view
- Who:
- you.
- How:
- without opening the casing, look at the flexible pipe running from the boiler to the drain, only where it is visible.
- Result that matters:
- whether it is kinked, loose or has water pooling around it.
- If something looks wrong:
- take a photo and tell the technician; Cointra asks for the siphon to be checked for A02.
- If it looks fine:
- the electrode or the board become more likely.
- Evidence to keep:
- a photo of the pipe and the floor under the boiler.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
A single reset with the reset key
- Who:
- you.
- How:
- hold the reset key on the panel for one second, as Cointra describes for A faults. Once only.
- Result that matters:
- whether the boiler works again without showing A02.
- If it works:
- note the day and time; if A02 returns another day, the technician should check the electrode and wiring.
- If it does not restart or A02 returns at once:
- Cointra says the fault must be fixed; leave it locked out and call.
- Evidence to keep:
- a photo of the display showing A02.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Electrode, wiring, siphon and board by the technician
- Who:
- authorised gas technician.
- How:
- with the power off and the gas closed, checks the electrode, whether the electrode or cable is earthed, the siphon and the board.
- Result that matters:
- where the false flame signal comes from.
- If the electrode or cable is earthed:
- that cause is confirmed and corrected.
- If all of that is fine:
- the board becomes the suspect.
- Evidence to keep:
- a report of what was checked, any part replaced and the combustion values.
Cointra says to switch off a faulty boiler and leaves repairs and part replacement to authorised technicians. Electrode, internal siphon and board are inside the casing.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
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
- Cointra
- Product type
- Gas boiler
Known code variants
- A-02
- A2
- Anomalía A02 Ferroli
- Beretta A 02
- Ciao Green A02
- Cointra A 02
- Error A02 Beretta
- Error A02 Cointra
- Error A02 Ferroli
- Ferroli A02 caldera
- Superlative A02
What it means
In the Superlative Plus fault table, A02 means flame signal present with the burner off. The board reads the flame through the electrode: if it sees a flame when there should be none, it locks the boiler out. Cointra points to the electrode (its condition, electrode earthed or cable earthed), asks for the siphon to be checked and lists a board fault. The letter A is a permanent lockout cleared with the reset key. The code does not tell which of these causes is at work.
Warnings and stop conditions
- Criticaleditorial warning
If you smell gas, do not reset or press anything electrical: open windows, close the gas tap if it is within reach, leave the home and call your gas distributor's emergency number from the street. Cointra says to switch a faulty boiler off and have it repaired only by an authorised technician.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Criticaleditorial warning
Cointra warns of a risk of asphyxia from escaping flue gases if the boiler runs with the siphon empty. Headache, dizziness or nausea can mean carbon monoxide: switch the boiler off, ventilate, leave and get help. Keep a CO alarm nearby.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Highsource verified
Do not keep pressing reset: the Cointra table has its own lockout, A64, when the maximum number of consecutive resets is exceeded. If A02 returns, leave it locked out.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Symptoms and causes
Probable causes · in order
- Electrode or its cable earthedPossible
Cointra says to check the electrode condition and whether the electrode or the cable is earthed. This is what makes the board read a flame that is not there.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Condensate siphonPossible
Within the A02 row, Cointra says to check the siphon and clean it if needed. It fits if the condensate drain does not run properly or there is water where there should not be.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Electronic boardPossible
Cointra lists a board fault and says to check it. It comes into play when electrode, cable and siphon are fine and A02 keeps appearing.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Virtual technician
Does A02 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
- 1
Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Cointra · 2017 · manual
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