He reads the boiler memory
The last codes and how often they appeared tell him whether the fault is new or has been building up for months.
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Buderus Error Codes
Is your Buderus boiler (Logamax plus GB172, GB192, Logano G125…) showing a code? Find out what it means in the table below. A code tells you where the boiler has detected a problem, not how to repair it. Our heating engineers work on Buderus gas and oil boilers 7 days a week, and the price is given before any repair.
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Buderus boiler repair
Codes such as 6A, 4C, 3C or EL mean the boiler has put itself in safety mode: it has detected an ignition failure, overheating, a fan problem or a control fault. One code can have several causes, and only measurements on site show which one is behind it.
Our engineer arrives with his measuring equipment. He tests the ignition, the ionisation current, the fan, the sensors and the circuit board, explains what he has found and gives you the price of the repair before starting. He carries the common Buderus spare parts so that most faults are fixed in a single visit.
Many Belgian homes still run a Buderus oil boiler (Logano G115, G125) next to a tank in the cellar. On those, the burner has its own control box and the faults are read differently: the technician knows both families, gas and oil.
Buderus boiler service: fewer codes, fewer breakdowns
Most codes that keep returning come from a dirty boiler: a worn electrode, a fouled burner, a blocked condensate trap or a combustion setting that has drifted. A regular service prevents them.
During the service, the technician cleans the burner and the heat exchanger, analyses the combustion, tests the safety devices and hands you the service attestation. He also reads the codes stored in the boiler memory: they show what happened since his last visit.
Buderus error code table
Type your code in the search box to find it straight away. Codes made of a digit and a letter (6A, 4C…) are faults; "-H", "=H" or "0H" are normal operating messages.
| Code | Service code (if shown) | Meaning | What the technician checks |
|---|---|---|---|
| -A | 208 | Appliance in chimney sweep mode (cleaning mode) | Chimney sweep mode switches itself off after 30 minutes. |
| -H | 200 | Boiler in heating mode | Normal operating state. |
| =H | 201 | Appliance in DHW mode (domestic hot water) | Normal operating state. |
| 0A | 202 / 305 | Cycle lock active / temperature maintenance (GB172-24K) | End of the hold cycle (service functions 2.3b / 2.3F). |
| 0C | 283 | Burner starting | Operating information. |
| 0E | 265 | Heat demand lower than minimum output — on/off operation | Normal behaviour when demand is low. |
| 0H | 203 | Appliance in standby (no heat demand) | Heat demand from the thermostat or controller. |
| 0L | 284 | Gas valve opening — first safety delay | Gas start-up and gas valve. |
| 0U | 270 | Appliance starting up | Operating information. |
| 0Y | 204 / 276 | Flow temperature > setpoint / flow temperature > 95 °C | Water circulation in the system, radiator valves, air in the circuit. |
| 2E | 357 | Air purge function active | Information — air purge in progress. |
| 2H | 358 | Anti-seize protection for circulation pump / 3-way valve active | Circulation pump and three-way valve if the code keeps coming back. |
| 2P | 342 | Gradient limit: temperature rising too fast in DHW mode | Domestic hot water operation. |
| 2Y | 282 | No rotation speed feedback from the circulation pump | Speed sensor and circulation pump. |
| 5H | 268 | Control system test | Service information. |
| 3C | 217 | Fan not running | Cables, connectors and fan, replaced if necessary. |
| 3L | 214 | Fan stopped during the safety delay | Electrical connections and fan. |
| 3P | 216 | Fan running too slowly | Fan and its power supply. |
| 3Y | 215 | Fan running too fast | Fan and flue gas system. |
| 4C | 224 | Heat exchanger temperature limiter or flue gas limiter triggered | Heat block, temperature limiters, wiring, operating pressure. |
| 4U | 222 | Flow sensor short-circuited | Flow sensor and its wiring. |
| 4Y | 223 | Flow sensor interrupted / defective | Flow sensor, replaced if faulty. |
| 6A | 227 | No flame detected (after 4 ignition attempts => lockout) | Gas supply, ignition and ionisation electrodes, gas valve. |
| 6L | 229 | No ionisation signal while the burner is running | Ionisation signal and electrode; without a repair, 6A follows. |
| 8Y | 232 | AT90 controller problem or jumper missing / condensate pump defective | AT90 controller or connection jumper, condensate pump. |
| EL | 290 | Base controller BC25 defective | BC25 base controller, replaced if faulty. |
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 any other code, write it down and call us: the technician knows what to look at and brings the right parts.
What the technician does when your Buderus shows a code
He measures before replacing
Ionisation, pressure, temperatures, fan speed, sensors: he looks for the real cause instead of swapping parts at random.
He repairs and explains
Price given upfront, repair, combustion test, then the job report and invoice are handed over.
What our customers say
Where do we work?
Our heating engineers repair and service Buderus boilers all over Belgium: in Brussels, in Wallonia and in Flanders. Call us and we will tell you straight away when a technician can be at your home.
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 6A mean on a Buderus boiler?
The boiler did not detect a flame after several ignition attempts and has locked out. The cause can be the gas supply, the ignition or ionisation electrode, or the gas valve: the technician finds it by measuring.
What does code 4C mean?
A temperature limiter on the heat exchanger or the flue gas has tripped: the boiler got too hot. The reason (water circulation, pump, fouling) has to be found before the boiler goes back into service.
Is "-H" or "=H" a fault?
No. "-H" means the boiler is heating the house and "=H" that it is making hot water. These are normal operating messages.
The code comes back after a restart: what should I do?
Write the code down and call us. A boiler that keeps going into safety mode has a real fault: restarting it again and again does not solve it and can make it worse.
Do you repair Buderus oil boilers?
Yes, Buderus gas boilers (Logamax plus GB172, GB192…) as well as oil boilers (Logano G125, G115…), for repairs and servicing.
How soon can a technician come?
For a breakdown we offer the first available slot, often the same day depending on where you live. The price is given before the work starts.
Is your Buderus showing a code?
Call us or book a slot online: a heating engineer comes to your home with the right parts.