No hot water
Sensor, charging pump, priority setting or controller; the tank itself is checked too.
Home › Heating › ACVService 7 days a week
ACV Heating Engineer: Boiler Repair, Servicing and Breakdowns
ACV is a Belgian manufacturer famous for its tank-in-tank technology, which gives plenty of hot water. Its Delta, HeatMaster and Prestige boilers and its Smart Line cylinders are found in homes, restaurants and small businesses across the country. We repair and service them in Brussels, Wallonia and Flanders, 7 days a week.
5,0on Google22 years of experiencePrice agreed before the work
Tank-in-tankDelta and HeatMaster
PrestigeWall-hung condensing
Homes and businessesLarge hot water needs
7 days a weekPrice given first
Delta and HeatMaster: boilers with built-in hot water
The idea behind ACV is simple: the domestic hot water tank sits inside the heating water, which surrounds and heats it. That is the tank-in-tank principle used in the floor-standing Delta boilers (oil or gas) and in the HeatMaster, which delivers a lot of hot water quickly and is popular in large houses, hair salons, restaurants and sports clubs.
These appliances are durable but need regular care: burner service, cleaning of the flue tubes, a check of the tank, the safety valve and the expansion vessel, and a combustion test. Neglected, they lose efficiency and the burner starts to lock out.
When there is no hot water or no heating, our engineer checks the burner, the controls, the circulators and the sensors. He explains what he finds and gives you the price before the repair.
Because ACV is a Belgian manufacturer, parts for most of its recent appliances are easy to source through Belgian wholesalers. For older Delta models, the engineer checks availability before the visit, so that the repair can be done as quickly as possible.
Prestige wall-hung boilers
ACV's wall-hung condensing gas boilers, sold under the Prestige name, also use tank-in-tank technology in their combi versions. They are found in flats and houses where a high hot water flow is wanted from a compact appliance. Their stainless steel construction copes well with hard water, which is one reason they are popular in many Belgian towns.
Their display shows a code when the boiler locks out: ignition, flame, temperature, water pressure or fan. The main codes are explained on our ACV error codes page. Our engineer uses the code as a starting point and confirms the cause with his measuring tools.
The service follows the usual steps for a condensing boiler: cleaning of the exchanger and burner, siphon, safety devices, combustion analysis and adjustment. You receive the maintenance attestation at the end.
Smart Line cylinders and hot water for businesses
Many installations combine any boiler with an ACV Smart Line indirect cylinder, also built on the tank-in-tank principle. When the hot water runs out too quickly or takes long to heat, the cause may be the cylinder's sensor, the charging pump, the priority setting or scale.
For businesses that depend on hot water (restaurants, salons, gyms, care homes), a breakdown is costly. We service these installations on a regular schedule and come quickly when something fails, 7 days a week.
We also size and install new ACV systems or other brands for professional premises, after a visit and a free quote.
Replacing an old ACV boiler
Some ACV Delta boilers have been working for decades. When the inner tank starts leaking, the boiler cannot be repaired and must be replaced. We tell you frankly when that point is reached.
Depending on the building, we propose a new condensing boiler with a tank-in-tank cylinder, a high-output water heater for a business, or an air-to-water heat pump for a well-insulated home, possibly in a hybrid setup.
The visit and the quote are free. Our team removes the old appliance, installs the new one and commissions it.
Typical ACV issues
These come up most on ACV equipment.
Water around the boiler
Safety valve, expansion vessel or, on old units, a leaking inner tank.
Burner lockout
Fuel supply, electrodes, photocell or gas pressure, depending on the burner.
Heating weak while hot water fine
Circulator, mixing valve or controller settings on the heating side.
How we handle your ACV call
Tell us
Model (Delta, HeatMaster, Prestige…), fuel, code and whether heating or hot water is affected.
Price first
Call-out and first hour announced; parts priced before fitting.
Repair or service
The engineer works, explains and leaves the job sheet and invoice.
What our customers say
ACV service throughout Belgium
We repair and maintain ACV boilers and cylinders all over Belgium: in Brussels, in Wallonia and in Flanders, for homes and for professional premises.
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 is tank-in-tank?
A hot water tank placed inside a larger tank of heating water, which heats it from all sides. It gives a lot of hot water and resists scale well.
Can you repair a leaking ACV Delta?
If the leak comes from a valve or a fitting, yes. If the inner tank itself leaks, the boiler must be replaced.
Do you work on ACV HeatMaster in restaurants?
Yes. We service and repair HeatMaster units and other ACV equipment in businesses.
Are you ACV's service department?
No. We are an independent firm that repairs and services ACV boilers and cylinders.
My Prestige shows a code. What should I do?
Note it and call 0477 03 88 98. Our ACV error codes page explains the most common ones.
How often should an ACV boiler be serviced?
It depends on the fuel and your Region. Oil boilers generally every year; we tell you the rule.
Do you come on Sundays?
Yes, 7 days a week. The supplement is announced beforehand.
Can an ACV cylinder be connected to another brand of boiler?
Yes. Smart Line cylinders work with most boilers and heat pumps. We check the connection, the pump and the controls so the hot water gets priority when needed.
ACV boiler not working?
Call us for a repair, book a service or ask for a free quote.