Ignition
Electrode, gas valve, trap.
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Broken Boiler: Fault Code Read, Cause Found, Repair Explained
In short: Our heating engineers find the real cause of the fault, tell you the cost before repairing and get your heating going again, for gas and oil boilers of all makes. Call 0477 03 88 98.
No heating, no hot water, a red light on the burner or a code on the display? Note the code and the make of the boiler before you call: the engineer will know where to look and bring the parts that match your model.
5,0on Google· 22 years of experience
All makesGas and oil
Cost firstBefore the repair
Job sheetAnd invoice
Combustion checkedAfter the repair
Reading the fault code and finding the real cause
A modern boiler shows a fault code when it locks out: F28 or F29 on Vaillant and Bulex, 6A on Buderus, EA on Junkers. The code tells you the family of the problem, such as ignition, flame, pressure, overheating or a sensor, but not always the exact part.
The engineer cross-checks the code with measurements: gas pressure at the inlet, flame ionisation current, flow and return temperatures, the condition of the pump. The same F28 can come from a closed gas valve, a worn electrode or a gas valve at the end of its life. Measuring avoids replacing a part that was working.
Our pages on the fault codes of the main makes help you understand what the boiler is telling you before the visit.
Repairing an oil burner
On an oil boiler, most breakdowns are at the burner: a dirty photocell that no longer sees the flame, a blocked nozzle, badly set electrodes, a tired ignition transformer or an oil pump that no longer draws properly.
The engineer takes the burner head apart, cleans or replaces worn parts, checks the pump pressure and sets the air supply. He also checks the filter and the suction line from the tank, because a burner short of oil locks out just like a faulty one.
After the repair he runs several full starts to make sure the boiler fires every time without locking out. If the chimney or flue is very dirty, he tells you: poor draught also makes a burner go into fault.
Checking the combustion after the repair
Getting a boiler running again is not enough; it must also burn properly. After changing an electrode, a gas valve or a fan, the engineer places his analyser probe in the flue and measures the CO, the CO2 and the flue temperature.
A high CO level is dangerous and wears the boiler faster; a poor setting also raises consumption. The engineer adjusts the boiler until the values are right and writes them on the job sheet.
If your yearly service is due soon, he can do it straight after: you save a second visit and receive the service attestation your insurer or landlord asks for.
Repair or replace an old boiler
A boiler of more than twenty years can still work very well. But when faults follow one another, parts are no longer made or the heat exchanger starts to leak, repairing becomes a poor calculation.
After the diagnosis the engineer tells you frankly what he thinks: repair to get through the winter, or plan a replacement. He weighs the age of the appliance, the state of the heat exchanger, the cost of the repair and your yearly consumption.
If you decide to replace, we come to see your installation and give you a quote for a gas condensing boiler, a new oil boiler or a heat pump. Meanwhile we repair what can be repaired so you are not left without heating.
The faults we repair most often
Ignition failure: electrode, ignition lead, gas valve or a blocked condensate trap. Seized pump: the circulating pump sticks after a summer without running, and radiators stay cold.
Diverter valve: heating works but hot water does not, or the other way round. Condensate trap: a blocked trap stops a condensing boiler from starting.
Loss of pressure: a leak, the safety valve or a flat expansion vessel. Circuit board: rarer, but a board damaged by damp or a power surge must be replaced.
What to do before the engineer arrives
Check that the gas is on, that the boiler has power and that the thermostat is asking for heat. Look at the pressure gauge: below about 1 bar when cold, the boiler may refuse to start.
You can reset the boiler once. If the code comes back, do not keep resetting: note the code and call us. On an oil burner, never press the reset button several times, because unburnt oil builds up in the combustion chamber.
Smell gas? Do not touch any switch, open the windows, go outside and call 112 from there.
Most frequent faults
Pump
Seized after the summer.
Diverter valve
Heating or hot water missing.
Pressure
Leak, valve or vessel.
When you call
The code
A photo of the display.
The make
And the model.
The pressure
The figure on the gauge.
Since when
And what you have tried.
From your call to the invoice
A short call
Address, appliance, what is wrong: the office writes it down and books a time.
No surprises
You know the call-out cost before anyone leaves; a replacement or a new installation gets a written quote.
On site
Diagnosis and explanation first, then your agreement, then the work. The documents come from Service Technic Belgium.
What our customers say
Where we work
We repair boilers across Belgium, in Brussels, Wallonia and Flanders.
BrusselsWalloon BrabantFlemish BrabantHainautNamurLiègeLuxembourgAntwerpEast FlandersWest FlandersLimburg
Frequently asked questions
My boiler shows a fault code: can I reset it?
Once, yes. If the code returns, the cause is still there: call us on 0477 03 88 98 and give us the code.
Do you repair boilers of all makes?
Yes: Vaillant, Bulex, Viessmann, Buderus, Remeha, Junkers, Saunier Duval, ACV, Atag, De Dietrich, Wolf, Intergas and other common makes, gas and oil.
Does the engineer carry the parts?
He carries the common parts for the most frequent faults. A specific part may have to be ordered; you are told when.
How much does a boiler repair cost?
The call-out cost is given on the phone and the repair cost on site, before the work. You then receive a job sheet and a detailed invoice.
Should the service be done at the same time?
If it is due soon, yes: it saves a second visit and you receive the attestation.
My boiler is rented or under contract: can you come?
Check your contract first; if in doubt, call us and we look at it together.
How do I book?
Call 0477 03 88 98, send us a WhatsApp message or book online with the « Book an appointment » button. Tell us the municipality and, in a few words, what is going on.
Is your boiler broken?
Call 0477 03 88 98 with the code on the display, or book online: an engineer comes to find the cause.