A23 Error in a Ferroli Boiler: PCB Fault and Solution

The A23 error on a Ferroli boiler indicates an anomaly in the parameters of the electronic board, also known as the PCB. In practice, the appliance stops validating its internal configuration and protects itself by entering a lockout that may cut off both heating and domestic hot water.

If you are having a problem with your boiler, you can use our free error code finder. From there, you can identify and solve all errors easily and effectively.

What the A23 means in the boiler’s electronics

This code points to a parameter fault in the PCB, not a combustion failure or a classic hydraulic problem. The control unit detects that the information stored or loaded on the board does not match what is expected and, for safety reasons, prevents the boiler from continuing to operate normally.

That lockout follows a simple logic: if the board cannot correctly recognise its own configuration, the appliance cannot reliably control ignition, modulation or the system’s basic commands. The response is usually immediate and decisive, like a switch being turned off to prevent further damage.

The A23 should not be interpreted as a minor fault. Although the appliance may sometimes start again after a reset, the error will usually reappear if the underlying cause is not corrected. Once the electronics enter that unstable state, the solution is no longer a household fix and requires technical diagnosis.

Why this fault appears on the board

The most common cause is a PCB misconfiguration. This can occur after an electrical incident, handling of the appliance, a failed update or simple corruption of internal data. The board, which acts as the boiler’s brain, is then left with inconsistent parameters and the system responds with A23.

Power supply problems can also play a part. An unstable supply, repeated brief outages or voltage spikes can affect the electronics’ memory, especially in appliances that have already accumulated many hours of operation and thermal wear. Under these conditions, the board behaves like a filing cabinet with key pages missing.

In some cases, the cause is not a one-off configuration error but an actual defect in the electronic board. When the internal memory, control circuit or a sensitive component begins to deteriorate, parameter readings fail persistently. At that point, a reset is no longer a solution and the repair requires a more thorough assessment.

What symptoms accompany the lockout

The most obvious symptom is that the appliance stops, but there is usually more to the behaviour than that. The boiler may try to start and stop immediately, refuse to provide heating or interrupt domestic hot water production without showing a flame, pressure or temperature fault. This pattern reveals that the problem lies in the control layer, not in the water or gas circuit.

That detail helps distinguish A23 from other, more mechanical warnings. When a sensor, pump or ignition system fails, the appliance usually leaves clues in the hydraulic behaviour or in the combustion attempt. With A23, on the other hand, the machine seems confused from within, as if its basic commands no longer had a reliable map.

The display does more than provide information: it also protects. If the electronics detect that they cannot guarantee a correct operating sequence, they stop the activity before the fault escalates. That is why the user experiences a sudden breakdown, when in reality the system is responding to an internal inconsistency that should not be forced.

What a user can check without opening the boiler

A complete reset may be useful as an initial test, always switching the boiler off and back on again using its normal controls. If the error appears only once after a power cut or an isolated incident, the board may sometimes recover. But if the code returns immediately, the clue is already clear: the problem was not temporary.

It is also worth checking whether there has been a recent power cut, whether other appliances in the home have experienced fluctuations or whether the boiler has a history of previous warnings. Although this information will not solve the fault, it helps the technician distinguish between a simple loss of memory and an established board failure.

What does not help is repeatedly attempting to reset it. Forcing repeated starts does not correct the internal configuration and only delays the appropriate intervention. With an electronic fault, the appliance does not need pressure; it needs readings, diagnosis and, if necessary, reprogramming or board replacement.

When technical assistance is needed

Professional intervention becomes necessary when the error does not disappear after a reset or when it returns regularly. At that point, the technician must inspect the PCB, verify the consistency of the parameters and check whether there is a recoverable alteration or an irreversible failure of the electronic module itself.

The repair may range from reprogramming the board to replacing it completely. The decision depends on the specific model’s architecture, the availability of spare parts and whether the internal memory can be restored. In a modern boiler, that difference may amount to saving the appliance or replacing its nervous system.

It is worth remembering that the board does not work alone. Before declaring the electronics dead, a qualified technician will usually check the power supply, connections, wiring continuity and the system’s overall condition. A poor connection can imitate a more serious fault, but only an orderly diagnosis can distinguish a temporary anomaly from a structural failure.

What happens if the problem lies in the memory or programming

In some models, the operating logic depends on parameters stored in memory that determine how the boiler starts, how it modulates and which safety limits it applies. If this data is altered, the display may show A23 even though the other components appear to be in good condition. The appliance does not appear to be broken; it is being misinterpreted by its own control unit.

When this happens, reprogramming may return the appliance to working order, provided the board can still write and read data normally. If the memory is damaged, the restoration attempt fails or only lasts for a short time. It is the kind of problem hidden behind a brief message and yet affecting the machine as a whole.

Modern electronics operate within very narrow margins. A small alteration in critical parameters can trigger a complete lockout. That is why A23 should not be dismissed as a generic warning: it is a sign that the boiler’s internal logic has lost consistency and requires serious inspection.

How it differs from other warnings from the same brand

Ferroli’s range of warnings includes codes relating to pressure, flames, ventilation, sensors or water circulation, whereas A23 points to another layer of the appliance: the board’s configuration. This difference is important because it prevents incorrect diagnoses and unnecessary repairs.

If the problem were hydraulic or related to combustion, the technical response would be different. However, when the electronic brain itself loses consistency, the priority changes completely. The fault is no longer in what the boiler does, but in how it decides to do it.

That is why the user’s experience is often confusing at first. Everything seems normal one moment and, the next, the appliance is unusable. The key lies in the nature of the warning: A23 is not about dirt, air or pressure, but about the integrity of the board and its internal parameters.

What risks are there if it is left unchecked

Ignoring the error will not usually fix it; at most, it will hide it for a while. A board with incorrect parameters may continue to fail intermittently, cause erratic starts or leave the user with unpredictable heating precisely when they rely on the appliance most.

In addition, continuing to use the appliance without resolving the cause may eventually worsen the condition of the electronic module. Repeated lockouts, constant resets and electrical instability are not neutral conditions for the board. Each unsuccessful attempt adds wear to a component that is already operating at the limit of its reliability.

From a maintenance perspective, A23 is a clear sign that the boiler needs professional assessment. An electronic fault cannot be overcome with patience; it is resolved by identifying whether the parameters need to be recovered, the PCB replaced or the electrical environment that affected it repaired.

What to remember before requesting a repair

The useful information in this case is specific: A23 is linked to the electronic board and its internal configuration. It does not point to a simple lack of water, a flame problem or a blocked pump. This narrows the search and helps reach the real cause sooner.

The best clue for the technician is usually knowing whether the fault appeared after a power cut, whether it was isolated or repetitive and whether the boiler had shown unusual behaviour before the lockout. This context saves time and avoids blind diagnoses, something especially valuable with control faults.

On a Ferroli boiler, the A23 error is a brain alarm, not a muscle alarm. The system remains the same on the outside, but inside, the board has lost the order it needs to issue commands safely. That is why the real solution is rarely to keep trying: it is to restore the consistency the electronics have lost, or replace them when there is no way back.