- Boilers
- Gas boiler
A08
Ferroli A08 on a gas boiler: overheat protection tripped
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Ferroli A08 is an overheat lockout on the heating flow. With the boiler cold, check the gauge reads about 1 bar, press reset for one second and, if A08 returns, call an authorised technician.
Safety first
Stop and check this first
- If you smell gas, do not reset: do not touch switches or light flames, open windows, close the gas valve if it is within reach, leave and call your distributor's emergency number from outside. Ferroli says to disconnect the boiler when it fails and have it repaired only by an authorised technician.
- Do not chain resets with A08: if it returns, the boiler is protecting itself from overheating. Do not open the boiler or touch the pump or sensor.
Safe checks you can perform
- Gauge pressure with the system cold
- One reset with the reset key
- Cold radiators or water noises
- Pump, bleeding and sensor check by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Circulation pump check
- Do not attempt this professional task: Heating sensor measurement
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.
Circulation pump check
What they doThe technician confirms the pump turns and moves water through the system.
They must show youthe pump running and water circulating.
In writingthe pump's condition and whether it was replaced.
Heating sensor measurement
What they doThe technician checks the sensor's position and measures it with a multimeter against Ferroli's specification.
They must show youthe measured value against the specification.
In writingthe part number of any replaced sensor and why.
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.
Gauge pressure with the system cold
- Who:
- you.
- How:
- with the boiler cold, read the gauge. Ferroli asks for about 1 bar cold and to restore it with the filling key if it drops below 0.8 bar, always closing it afterwards.
- Result that matters:
- whether the pressure is right or low.
- If it is below 0.8 bar:
- top up as Ferroli says; afterwards the boiler runs a 300 second purge (Fh).
- If it is fine:
- lack of water does not explain A08; go on to the reset.
- Evidence to keep:
- a photo of the gauge before and after.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
One reset with the reset key
- Who:
- you.
- How:
- press the reset key for one second, as Ferroli says for A faults.
- Result that matters:
- whether the boiler restarts and heats the radiators.
- If it restarts and the radiators warm up:
- note the date; watch whether A08 returns.
- If it does not restart or A08 returns:
- Ferroli says the fault must be fixed; call an authorised technician.
- Evidence to keep:
- a photo of the display with A08 and the time.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
Cold radiators or water noises
- Who:
- you.
- How:
- after a few minutes running, carefully feel the radiators and listen for air or gurgling.
- Result that matters:
- whether heat reaches the system.
- If the boiler locks out with cold radiators:
- it points to circulation or air; tell the technician.
- If the radiators heat normally:
- it points more to the sensor.
- Evidence to keep:
- a note of which radiators were cold.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
Pump, bleeding and sensor check by the technician
- Who:
- authorised technician.
- How:
- checks the circulation pump, bleeds the system and checks the heating sensor's position and operation.
- Result that matters:
- which of Ferroli's three causes is present.
- If the pump does not move water or there is air:
- that confirms the cause.
- If it circulates well and the sensor fails:
- that confirms the sensor.
- Evidence to keep:
- a report of what was checked and any part replaced.
Ferroli reserves repairs and component replacement for authorised technicians: opening the boiler is not the user's job.
Evidence: Ferroli BLUEHELIX TECH RRT 28 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
- Ferroli
- Product type
- Gas boiler
Known code variants
- A 08
- A8
- Beretta A 08
- Bluehelix A08
- Ciao Green A08
- Cointra A 08
- Error A08 Beretta
- Error A08 Cointra
- Error A08 Ferroli
- F08 Ferroli
- Ferroli A 08
- Superlative A08
What it means
In the BlueHelix Tech RRT fault table, F08 and A08 are the overheat protection, watched by the heating sensor. Ferroli gives three causes: a faulty heating sensor, water not circulating in the system (circulation pump) or air in the system. The letter A means a permanent lockout cleared with the reset key. The code does not say which of the three causes is at work.
Warnings and stop conditions
- Criticaleditorial warning
If you smell gas, do not reset: do not touch switches or light flames, open windows, close the gas valve if it is within reach, leave and call your distributor's emergency number from outside. Ferroli says to disconnect the boiler when it fails and have it repaired only by an authorised technician.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
- Mediumsource verified
Do not chain resets with A08: if it returns, the boiler is protecting itself from overheating. Do not open the boiler or touch the pump or sensor.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
Symptoms and causes
Probable causes · in order
- Water not circulatingPossible
Ferroli says to check the circulation pump. It fits if the boiler heats up but the radiators stay cold before the lockout.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
- Air in the systemPossible
Ferroli says to bleed air from the system. It usually goes with gurgling, a recent top up or low pressure on the gauge.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
- Heating sensor faulty or out of placePossible
Ferroli says to check the sensor's position and operation and replace it if needed. It is the explanation if water circulates and there is no air.
Evidence: Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
Virtual technician
Does A08 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
Ferroli BLUEHELIX TECH RRT 28 C instrucciones de uso instalación y mantenimiento
Ferroli · 2018 · manual
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