- Boilers
- Gas boiler
A88
Cointra A88 on a gas boiler: combustion or gas valve error
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Cointra A88 means a specific combustion control or gas valve error. If you smell gas or fumes, leave the home. If not, press reset for one second, once; if A88 returns, leave it locked out 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 A88 returns, leave it locked out.
Safe checks you can perform
- Gas or flue gas smell near the boiler
- When A88 appeared
- A single reset with the reset key
- Calibration and combustion by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Full manual calibration
- Do not attempt this professional task: Gas valve and board check
- Do not attempt this professional task: CO2 measurement with an analyser
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.
Full manual calibration
What they doThe technician resets A88 and carries out the full manual calibration with the cover closed and the air and flue ducts fitted, as Cointra requires.
They must show youthe finished calibration on the display.
In writingthat it was done and the result.
Gas valve and board check
What they doIf A88 returns after calibration, checks the gas valve and the electronic board, replaces the one at fault and then repeats the full calibration.
They must show youthe part removed.
In writingthe reference of the part replaced and the reason.
CO2 measurement with an analyser
What they doConnects a combustion analyser to the flue accessory test point and checks CO2 at maximum and minimum output.
They must show youthe analyser printout.
In writingthe CO2 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)
When A88 appeared
- Who:
- you.
- How:
- take a photo of the display and note whether A88 appeared after a service, an adjustment or a part replacement, or for no clear reason.
- Result that matters:
- whether it matches a recent visit.
- If it appeared after a visit:
- tell the technician; Cointra names calibration started with the burner lit.
- If it appeared for no reason:
- go on to the single reset.
- Evidence to keep:
- a photo of the display, the date and the last visit.
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 A88.
- If it works:
- note the day and time; even so, Cointra calls for a full manual calibration after A88.
- If it does not restart or A88 returns at once:
- leave it locked out and call the technician.
- Evidence to keep:
- the reset result.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Calibration and combustion by the technician
- Who:
- authorised gas technician.
- How:
- resets the fault, carries out the full manual calibration and checks CO2 with an analyser; if that does not fix it, checks the gas valve and board.
- Result that matters:
- whether CO2 is within the table and A88 does not return.
- If calibration fixes it:
- the cause was the setting or combustion.
- If A88 returns after calibration:
- the gas valve or the board become the suspects.
- Evidence to keep:
- the analyser printout, the calibration done and parts replaced.
Calibration, the gas valve and the board require opening the boiler, entering the service menu and using an analyser. Cointra leaves these operations 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 88
- Cointra A 88
- Error A88 Cointra
- Superlative Supra A88
- Supra A88
What it means
In the Superlative Supra C fault table, A88 groups specific combustion control or gas valve errors. Cointra gives two causes: calibration was started with the burner lit, or there is a combustion, gas valve or electronic board problem. The manufacturer's remedy is to reset the fault and carry out the full manual calibration and, if needed, replace the gas valve or the board. The letter A is a permanent lockout. The code does not say which part is failing.
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 A88 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
- Calibration started with the burner litPossible
This is the first cause Cointra gives. It fits if A88 appeared right after a service, an adjustment or a part replacement in which calibration was started.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Combustion problemPossible
Cointra names a combustion problem. It shows up on the analyser: the CO2 measured is outside the manufacturer's table.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
- Faulty gas valve or electronic boardPossible
Cointra allows for replacing the gas valve or board if calibration does not solve it. It comes into play when A88 returns after a correct calibration.
Evidence: Cointra SUPERLATIVE SUPRA C, instrucciones de uso, instalación y mantenimiento (cod. 3541V210)
Virtual technician
Does A88 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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