Failed ignition (E01)
Worn or misaligned electrode, low gas pressure, tired gas valve: the most common code in winter.
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ACV Error Codes
Has your ACV boiler (Prestige, HeatMaster, Delta…) stopped with a code beginning with "E"? The table below gives the meaning of the codes shown by the ACVMax control. These Belgian boilers, often with a built-in hot water tank, need an engineer who knows them: we come out 7 days a week and tell you the price before the repair.
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ACV boiler repair
ACV is a Belgian manufacturer that has been based near Brussels for decades. Its Prestige condensing boilers and its HeatMaster units with an integrated cylinder are found in many homes and small buildings across the country, running on gas or on oil. Their "tank-in-tank" design, a hot water cylinder immersed in the heating water, makes them very comfortable but also rather different from ordinary wall-hung boilers.
When the ACVMax control detects a fault, it shuts the burner down and displays a code: E01 for a failed ignition, E03 for excessive temperature, E05 for a fan running at the wrong speed. Some codes clear by themselves once the cause disappears, others lock the appliance until someone intervenes.
Our engineer reads the fault memory, measures the ionisation current and the gas pressure, tests the flow and return sensors, then explains what he found and the cost of the repair before carrying it out. On a HeatMaster he also looks at the inner tank and its safety devices.
Servicing an ACV boiler
A Prestige that frequently shows E01 or E02 nearly always has a fouled electrode or a burner in need of cleaning. On oil models, a worn nozzle or a clogged filter cause the same symptoms. Regular servicing removes most of these stoppages.
During the service the technician dismantles and cleans the burner, inspects the heat exchanger, sets the combustion with an analyser and checks the condensate trap. You then receive the service attestation required for your boiler.
He also notes the codes stored in memory: a string of lockouts since the last visit is a warning sign worth taking seriously, especially before winter.
ACV error code table (ACVMax control)
These codes apply to ACV boilers fitted with the ACVMax control (recent Prestige models). Older generations and oil boilers with a separate burner may display things differently: write down what the screen shows and call us.
| Code | Meaning | What the technician checks |
|---|---|---|
| E01 | Ignition failure: the burner did not light after 5 attempts | Gas supply, ignition electrode, ignition lead, gas valve. |
| E02 | False flame: a flame is detected before ignition | Fouled electrode, earthing, control board. |
| E03 | Boiler temperature too high | Water circulation, circulating pump, flow sensor, heat exchanger. |
| E05 | Incorrect fan speed or no speed signal | Fan, wiring and connectors, ACVMax board. |
| E08 | Flame circuit error (test failed) | Flame detection circuit and control board. |
| E09 | Gas valve circuit error (test failed) | Gas valve, gas valve wiring, control board. |
| E12 | Internal fault: wrong memory configuration (EEPROM) | Control settings, board replaced if necessary. |
| E13 | Maximum number of restarts reached | Cause of the repeated lockouts: the original fault is traced. |
| E16 | Flow sensor stuck: its value no longer changes | Flow sensor, contact with the pipe, wiring. |
| E17 | Return sensor stuck: its value no longer changes | Return sensor and its wiring. |
| E18 | Sensor fault: flow or return value changes too fast | Sensors, water circulation, air in the system. |
| E19 | Flame lost during the start-up phase | Gas pressure, ionisation electrode, combustion setting. |
| E25 | Internal control fault (CRC check) | ACVMax circuit board. |
Code not in this table: call us, our technician knows it.
Smell of gas? Do not touch any switch, open the windows, leave the house and call 112 from outside. For an E code, note it exactly, digits included, before calling: the technician prepares the matching parts.
Recurring faults on ACV boilers
Overheating (E03)
The heating water no longer flows enough: seized pump, closed valves or sludge in the system.
Fan (E05)
Worn bearings or an oxidised connector: the fan no longer reaches the speed the control asks for.
Sensors (E16 to E18)
A loose sensor or a damaged cable distorts the reading and causes repeated stops.
Built-in tank
On a HeatMaster, lukewarm hot water often comes from scale or a badly set valve.
What the technician does on your ACV
He reads the stored faults
The list of recent codes shows whether the fault is a one-off or has been coming back for weeks.
He measures before replacing
Ionisation, gas pressure, fan speed, sensor values: each part is tested before it is changed.
He repairs and adjusts combustion
Price announced first, repair, analyser setting, then job report and invoice.
What our customers say
Where do we work?
Our heating engineers work on ACV boilers throughout Belgium: in Brussels, in Wallonia and in Flanders. Tell us your code and your town, and we will give you a possible arrival time.
BrusselsWalloon BrabantFlemish BrabantHainautNamurLiègeLuxembourg provinceAntwerpEast FlandersWest FlandersLimburg
The brands we work with
Our technicians work on all brands: they install, service and repair appliances from the major manufacturers. For a new installation, we recommend the model that suits your home and budget.
We buy our equipment from all the major Belgian wholesalers and suppliers, including Facq, Van Marcke and Desco: genuine parts, quickly available.
Frequently asked questions
What does code E01 mean on an ACV boiler?
The burner did not light after five attempts. The cause may be the gas, the electrode, the ignition lead or the gas valve: the technician finds it by measuring.
Is code E03 serious?
It reports an excessive temperature inside the boiler. The boiler protects itself, but the reason the water no longer circulates must be found before it runs again.
What does E13 mean?
The control has counted too many restarts in a short time. It is not the fault itself: the original problem is still there. Write the code down and call us.
Do you repair ACV HeatMaster units?
Yes, gas and oil HeatMasters as well as wall-hung and floor-standing Prestige models, for repairs and servicing.
My ACV shows no code but no longer heats: what should I do?
Note what the screen shows, or whether it is blank, and call us: a power supply or board fault can prevent the display from working.
When can a technician come?
We offer the first available slot, often the same day depending on where you live. The price is given before any work.
Your ACV shows a code?
Call us or pick a time online: a heating engineer who knows ACV boilers comes to your home.