Maintenance · Gas boiler
Gas boiler servicing
Every 2 years in Brussels and Flanders (from 20 kW), every year if you want to keep most manufacturers' warranty. Cleaning, flue-gas analysis, tuning and official certificate.
Schedule my maintenance+32 15 62 70 80
- 1,100+ customers serviced in 2 years
- Certified gas and oil technicians
- Official certificate provided
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What the law says
Brussels
Inspection every 2 years by a certified technician (GI or GII), who records the certificate with Brussels Environment. The tenant arranges it unless the lease says otherwise.
Flanders
From 20 kW: every 2 years, by a certified technician. The certificate lands in your Woningpas; a refused boiler still in use can cost you your fire insurance.
Our advice
Every year: it is most manufacturers' warranty condition, and 6 out of 10 gas boiler services replace a wear part, most often the burner gasket (€30 to €45 excl. VAT).
Sources: Brussels Environment (19/01/2025), vlaanderen.be (read on 09/11/2026), Regulation (EU) 2024/573 on fluorinated gases.
What we check at each maintenance
The points of the sheet our technicians fill in at every visit, one by one.
Appliance servicing
- General condition checked: cleanliness, tightness, wear, operation
- Casing and electronics dusted
- Burner cleaned
- Electrodes cleaned and set
- Heat exchanger cleaned
- Condensate drain checked, siphon cleaned and filled
- Burner set to the manufacturer's values
Flue and air
- Flue checked and cleaned, or the sweep's certificate seen
- Combustion air duct checked (room-sealed appliance)
Hydraulics and controls
- Circulator works
- Thermostat talks to the boiler
- Valves and air vents work, no leak
Safety
- Measuring ports sealed again
- Safety devices
The measurement
With the analyser, not by eye.
- Combustion analysed before and after the work
- CO, efficiency and flue gas temperature
- Compared with the legal limits of your region
- The analyser's report kept as proof
- Ambient CO measured on arrival and in front of the appliance
One-off service or maintenance contract
Two ways to have your appliance serviced: on request, or without giving it another thought.
One-off service
You call us when the due date nears, we schedule the visit, you pay for the service.
- The same full service and the certificate
- No commitment
Maintenance contract
We remind you before the due date and schedule the visit for you, at the pace of the chosen plan.
- Reminder and scheduled visit
- Fixed price per appliance, known in advance
- History and certificates in your customer area
Why service
19
deaths a year in Belgium
Carbon monoxide is the first cause of fatal accidental poisoning. In Brussels, 2 to 3 people are poisoned every week, mostly by poorly maintained heaters and water heaters.
Poison Centre, 2018 to 2023 average; be.brussels, 15/10/2025
+5 %
more consumption
A poorly maintained boiler uses about 5% more: a well-tuned burner shows straight on the bill.
2 years
of legal warranty, without proof of servicing
Without proof of servicing, the warranty often stops there. Vaillant grants its 3 extra years only to a serviced appliance, Viessmann asks for a maintenance contract.
Frequently asked questions
Let us schedule your next service
Tell us your appliance and your municipality: we suggest a date.