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Heating engineer · Brussels and Wallonia
Vaillant error codes
The most common codes for Vaillant gas boilers (ecoTEC and others) and turboMAG and atmoMAG water heaters, with what they mean and what to do.
On the most recent models the codes have three digits: F.022 instead of F.22, F.028 instead of F.28. The meaning is the same.
The code is shown with a dot (F.22), but often searched without one (F22): it's the same code.
Not enough water in the boiler: the pressure is too low.
PressureCheck the pressure gauge. If it's too low, top up the water (if you know how) and bleed the radiators. If the pressure drops again, there's probably a leak: call us.
No flame detected at ignition: the boiler won't start.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
The flame went out and relighting failed.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
When the pump starts, the pressure barely changes: often low water or air in the system.
PressureCheck the pressure gauge. If it's too low, top up the water (if you know how) and bleed the radiators. If the pressure drops again, there's probably a leak: call us.
Overheating: the safety temperature limiter has shut off the gas.
CirculationCheck the pressure and that the radiator valves are open. If everything looks fine and the code comes back, the water circulation needs checking (pump, bleeding, sensors): call us.
Too big a temperature difference between flow and return: the water isn't circulating well.
CirculationCheck the pressure and that the radiator valves are open. If everything looks fine and the code comes back, the water circulation needs checking (pump, bleeding, sensors): call us.
Flue gas temperature too high.
Flue · safetySwitch the boiler off and air the room. This code concerns the flue: call us. If a CO alarm goes off, or anyone has a headache or nausea, get everyone outside and call 112.
Air pressure switch fault (air intake or flue).
Flue · safetySwitch the boiler off and air the room. This code concerns the flue: call us. If a CO alarm goes off, or anyone has a headache or nausea, get everyone outside and call 112.
A flame is detected while the burner is off.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Hot water cylinder temperature sensor short-circuited.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Control electronics fault (circuit board or gas valve).
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
The flame goes out late when the burner stops.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
turboMAG and atmoMAG gas water heaters
Water heater: ignition failed at start-up.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
Water heater: the flame went out during operation.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
Water heater: a flame is detected while the gas should be off.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Water heater: the temperature limiter shut the appliance down.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
turboMAG water heater: fault with the pressure switch or the flue fan.
Flue · safetySwitch the boiler off and air the room. This code concerns the flue: call us. If a CO alarm goes off, or anyone has a headache or nausea, get everyone outside and call 112.
turboMAG plus: the burner switched off after 45 minutes of continuous use. Close the hot tap for a moment.
TemporaryThe boiler restarts on its own once the cause is gone. If the code keeps coming back, call us for a check.
The atmoMAG has no display: its light flashes red when there's a fault. Most often: gas off, air in the gas pipe or not enough water pressure. Wait 10 minutes before switching it back on.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
This code isn't in the list: call us and give it to us, we'll tell you straight away what's going on.
Source: Vaillant Belgium, official error code list (vaillant.be) and ecoTEC plus operating instructions; water heaters: turboMAG (0020291138, 0020261983) and atmoMAG (0020271932) manuals. Codes and how they're shown can differ between models: if in doubt, your appliance's manual applies.
First steps
- Write down the code shown: it saves us time.
- Check the pressure gauge.
- Check that the gas tap is open.
- Reset once. If the code comes back, call us.
Practical guides: Top up the pressure · Bleed a radiator · Reset the boiler
A breakdown, a question? Get in touch.
Call us or message us on WhatsApp. Or leave your number, with a photo of the boiler if you like: we'll call you back.
