- Boilers
- Gas boiler
A07
Cointra A07 on a gas boiler: flue gas temperature too high
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Cointra A07 means the flue sensor is measuring a flue gas temperature that is too high. If you smell gas or fumes, leave the home. If not, press reset for one second, once; if A07 returns, leave it off and call the 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 or the flue circuit is not sealed. 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 Superlative Supra table has its own lockout, A64, when the maximum number of consecutive resets is exceeded, and the power then has to be cut for 60 seconds. If A07 returns, leave it locked out.
Safe checks you can perform
- Gas or flue gas smell near the boiler
- How often A07 appears
- Flue terminal from outside
- A single reset with the reset key
- Heat exchanger, flue sensor and b20 by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Heat exchanger cleaning
- Do not attempt this professional task: Flue sensor and b20 check
- Do not attempt this professional task: Combustion analysis
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.
Heat exchanger cleaning
What they doThe technician inspects the heat exchanger and burner and cleans them with a suitable brush, without chemicals, as Cointra describes.
They must show youthe condition before and after.
In writingthe cleaning done and the condition of the insulation.
Flue sensor and b20 check
What they doChecks the flue sensor and that parameter b20 matches the material of the flue installed.
They must show youthe b20 value on the display.
In writingthe setting found, the final setting and whether the sensor was replaced.
Combustion analysis
What they doWith an analyser in the flue accessory test point and TEST mode on, checks CO2 at maximum and minimum output against Cointra's table.
They must show youthe analyser printout.
In writingthe values measured against the manufacturer's specification.
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 note the code.
- Evidence to keep:
- the time and what you noticed.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
How often A07 appears
- Who:
- you.
- How:
- take a photo of the display and note the time each time A07 or F15 appears.
- Result that matters:
- whether it repeats and how many times in a day.
- If it appears 3 times in 24 hours:
- the boiler will move to A14; stop resetting.
- If it appeared once only:
- go on to the single reset.
- Evidence to keep:
- photos of the display with date and time.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Flue terminal from outside
- Who:
- you, only from the ground or a window, without climbing ladders.
- How:
- look at the flue outlet terminal and notice whether it is damaged, covered or warped by heat.
- Result that matters:
- whether the terminal looks normal or damaged.
- If it is damaged or warped:
- do not use the boiler and tell the technician.
- If it looks normal:
- the problem is inside the boiler.
- Evidence to keep:
- a photo of the terminal.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
A single reset with the reset key
- Who:
- you.
- How:
- only if there is no smell of gas or fumes, hold the reset key for one second, as Cointra describes for A faults. Once only.
- Result that matters:
- whether the boiler works again without A07.
- If it works:
- note the day and time; if A07 returns, the technician should check the exchanger, sensor and b20.
- If it does not restart or A07 returns at once:
- Cointra says the fault must be fixed; leave it locked out and call.
- Evidence to keep:
- the reset result.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Heat exchanger, flue sensor and b20 by the technician
- Who:
- authorised gas technician.
- How:
- inspects and cleans the heat exchanger, checks the flue sensor and checks parameter b20 against the flue installed.
- Result that matters:
- whether the flue gases really are hot or the reading is false.
- If the exchanger is dirty:
- it is cleaned and combustion is checked.
- If it is clean and b20 is correct:
- the flue sensor becomes the suspect.
- Evidence to keep:
- a report with what was checked, the b20 value and parts replaced.
The heat exchanger, flue sensor and parameter menu are inside the casing or protected by a code. Cointra leaves the annual service and repairs to authorised technicians.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
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 07
- A7
- Beretta A 07
- Ciao Green A07
- Cointra A 07
- Error A07 Beretta
- Error A07 Cointra
- Superlative Supra A07
- Supra A07
What it means
In the Superlative Supra C fault table, A07 is high flue gas temperature: the flue sensor detects an excessive temperature. The table lists it together with F15; F faults are temporary lockouts and A faults are permanent. Cointra says to check the heat exchanger, the flue sensor and the flue material parameter, b20. If A07 occurs 3 times in 24 hours, the boiler moves to A14, flue outlet safety device tripped. The code does not say whether the heat is real or a false reading.
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 SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Criticaleditorial warning
Cointra warns of a risk of asphyxia from escaping flue gases if the boiler runs with the siphon empty or the flue circuit is not sealed. 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 SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Highsource verified
Do not keep pressing reset: the Superlative Supra table has its own lockout, A64, when the maximum number of consecutive resets is exceeded, and the power then has to be cut for 60 seconds. If A07 returns, leave it locked out.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Symptoms and causes
Probable causes · in order
- Dirty or scaled heat exchangerPossible
Cointra asks for the heat exchanger to be checked, and its annual service requires burner and exchanger to be clean. It is the cause when the flue gases really are hot.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Faulty flue sensorPossible
Cointra asks for the flue sensor to be checked. It is the cause when the exchanger is clean and the sensor gives a reading that does not match.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Flue material parameter set wronglyPossible
Cointra asks for parameter b20 to be checked, which selects standard, PVC or CPVC. It is a settings check, not a parts check, and fits if it does not match the flue installed.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Virtual technician
Does A07 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
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