Ferroli A63 Fault Code: Causes, Fixes & Repair Costs
What does the Ferroli A63 fault code mean?
The A63 fault code on a Ferroli boiler signals an internal electronics fault with the boiler's main control board (PCB). Depending on which controller your Ferroli model uses, this may be described as a PCB AGC01 fault, a Controller ABM03B error, or a Controller DBM12 fault — but in every case the boiler's own electronics have detected a problem with their internal operation or with how the board communicates with key components. A63 is a hard lockout code (codes starting with 'A' on Ferroli boilers are lockout faults), meaning the boiler has shut itself down and will not restart without a manual reset. The closely related A64 code falls into the same controller-fault family and points to the same underlying issue. Because the PCB is the brain of the boiler — controlling ignition, modulation, safety checks, and component communication — a fault here prevents the entire appliance from operating safely until the root cause is resolved.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Faulty or failed PCB Common
The control board itself has developed an internal fault — this might be a failed component on the board, moisture ingress, or age-related deterioration. Because A63 is specifically a controller-board error code, a genuinely faulty PCB is the most frequent end diagnosis when wiring checks come back clean.
- Loose or damaged wiring to the PCB Common
A poor connection, corroded terminal, or broken wire between the PCB and another component can disrupt the signals the board expects to see, triggering a self-diagnosed controller error. An engineer will test the circuit with a multimeter and can often resolve this with a rewire or connector repair at far lower cost than a full board replacement.
- Transient electrical disturbance or power surge Sometimes
A brief voltage spike or power interruption can occasionally cause the PCB to enter a fault state even when the hardware is otherwise sound. In these cases a single manual reset clears the code permanently and no further action is needed.
- Communication fault between PCB and a connected component Sometimes
If a sensor, pump, fan, or gas valve develops a fault, the PCB may flag the problem as a controller error rather than isolating the specific component. The A63 code can therefore sometimes be a secondary symptom of another failing part that the board can no longer communicate with correctly.
How to fix it
- Check your gas supply is live DIY safe
Before anything else, confirm other gas appliances in your home (hob, fire) are working normally. If there is no gas supply to the property, contact your gas supplier rather than investigating the boiler further.
- Attempt a single manual reset DIY safe
Locate the reset button on your Ferroli's control panel — it is usually marked with the letter R. Press and hold it for one to two seconds. If the boiler fires up and runs normally, monitor it over the next few hours. A one-off transient fault can clear this way.
- Do not reset the boiler repeatedly DIY safe
If the A63 code returns after your first reset attempt, do not keep pressing reset in the hope it will clear. Repeatedly forcing a boiler with a genuine PCB fault to restart can cause additional damage to the heat exchanger or fan. Two to three resets is the absolute maximum before calling a professional.
- Check system pressure DIY safe
While you are waiting for an engineer, glance at the pressure gauge. Ferroli boilers typically need to sit between 1 and 1.5 bar when cold. If pressure is below 1 bar, top up via the filling loop according to your boiler's user guide. Low pressure alone will not cause A63, but it is worth correcting before the engineer arrives.
- Call a Gas Safe registered engineer to inspect the PCB and wiring Gas Safe engineer
A Gas Safe engineer will use a multimeter to carry out electrical continuity and voltage tests on the control board and its wiring harness. They will check for broken circuits, corroded connectors, and damaged wire insulation. If a loose or broken connection is found, a rewire or connector replacement may resolve the fault at relatively modest cost.
- PCB repair or replacement (engineer only) Gas Safe engineer
If the wiring is sound but the board itself has failed, the engineer will source a compatible replacement PCB for your specific Ferroli model and fit it. This is the most common outcome for a persistent A63 fault and the most significant cost involved. The engineer should test the boiler through a full heating and hot water cycle after fitting the new board to confirm the fault is cleared.
Parts you may need
- Ferroli main PCB (control board) · from £180
- Wiring harness / loom · from £45
- PCB connector/terminal repair kit · from £12
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £150–£380, depending on the underlying cause.
Frequently asked questions
Can I fix a Ferroli A63 fault myself?
No. The A63 code is a PCB and controller electronics fault, and working on a boiler's control board or its associated wiring is not a job for a homeowner. The only DIY steps you should take are checking your gas supply, attempting one reset, and topping up system pressure if it is low. Everything beyond that requires a Gas Safe registered engineer with the right electrical test equipment.
How much does it cost to fix a Ferroli A63 fault in the UK?
Most people with an A63 fault pay somewhere between £150 and £380 all in, depending on whether the issue is a loose wire (cheaper) or a full PCB replacement (more expensive). A diagnosis call-out typically costs £80–£150 on its own. If the board needs replacing, parts and labour combined usually fall in the £250–£380 range. In rare cases — particularly on older or less common Ferroli models where the PCB is hard to source — total costs can exceed £500, at which point replacing the boiler is often the more sensible decision.
What is the difference between Ferroli A63 and A64?
Both A63 and A64 sit in the same controller-board fault family and are handled in the same way. On models using the ABM03B controller they are often grouped together alongside F66 and all point to an internal controller error. In practice an engineer will diagnose and repair them using the same process — electrical testing of the PCB and wiring harness — so encountering either code leads you to the same course of action.
Is it worth repairing a Ferroli boiler with an A63 fault, or should I replace it?
That depends mainly on the age of your boiler. If it is under 10 years old and otherwise well-maintained, a PCB replacement is usually worth the cost. If it is over 10–12 years old and the repair bill is approaching 30–40% of what a new boiler would cost, replacement often makes more financial sense — particularly because an ageing PCB fault can signal wider electrical wear throughout the appliance. A Gas Safe engineer can give you an honest assessment once they have inspected the boiler.