Burner will not start
E04.10 on gas models, burner lockout on oil models: fuel supply, electrodes, nozzle or gas valve.
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Has your De Dietrich boiler stopped with a code such as E04.10 or H01.08? Here is what the most common codes of the recent De Dietrich range mean. De Dietrich belongs to the same group as Remeha, and its latest wall-hung boilers share the same coding. We repair De Dietrich gas and oil boilers 7 days a week, with a price given beforehand.
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The French-German brand De Dietrich is known in Belgium for two very different families. On one side, the wall-hung condensing gas boilers such as the Naneo and Evodens. On the other, the robust cast-iron floor-standing boilers, often running on oil, that equip many detached houses.
The wall-hung models of the latest generation display a letter followed by four digits. The letter matters: H is a blocking that clears itself when conditions return to normal, E is a lockout that keeps the boiler off. The failed start E04.10 is the one we are called for most.
Floor-standing oil boilers and older De Dietrich control panels (Diematic) show their faults differently. Our engineers know these installations and read the information on site, whatever the age of the boiler.

For each code, the technician starts with measurements: gas or oil pressure, ionisation current, flow and return temperatures, fan speed, combustion values. Only then does he decide which part is at fault.
You are told what he has found and the price of the repair before he starts. When the yearly service is due, he cleans the boiler, analyses the combustion and leaves the service attestation.
Codes of the recent De Dietrich wall-hung boilers. Search for yours; for older models and oil boilers, call us and the engineer will read the fault on site.
| Code | Meaning | What the technician checks |
|---|---|---|
| H02.02 | Waiting for the configuration number | Configuration numbers CN1 / CN2, typically after a board has been changed. |
| H02.03 | Configuration error | Configuration numbers, control board. |
| H02.04 | Parameter error | Parameter settings, control board. |
| H02.05 | Memory unit (CSU) does not match the control unit (CU) | Memory unit and control board. |
| H01.05 | Maximum difference between flow and return temperature exceeded | Circulation in the heating circuit, pump, sensors. |
| H01.08 | Heating flow temperature rising too fast | Pump, circulation, air in the system. |
| H01.14 | Maximum flow temperature exceeded | Pump, circulation, flow sensor. |
| E04.08 | Safety input open | Safety devices wired to the input. |
| E04.10 | Burner failed to start after five attempts | Gas supply, ignition electrode, gas valve, flue, siphon. |
| E04.12 | False flame signal | Ionisation electrode, wiring, gas valve. |
| E04.13 | Fan blade stalled | Fan and wiring. |
| E04.17 | Gas valve driver fault | Gas valve, control board. |
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.
E04.10 on gas models, burner lockout on oil models: fuel supply, electrodes, nozzle or gas valve.
H01.05, H01.08 or H01.14: the water does not circulate well enough. Pump, valves and air in the circuit are examined.
H02.02 to H02.05: the new electronics are not configured yet. The engineer enters the right configuration.
Ageing cast-iron boilers and Diematic panels: repair when it makes sense, free quote for a replacement when it does not.
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De Dietrich boilers are repaired and serviced by our engineers everywhere in Belgium, from Brussels to Wallonia and Flanders. Call us to know when a technician can come round.
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.
The burner did not start after five attempts and the boiler locked out. The gas supply, the ignition electrode, the gas valve, the flue and the siphon are the parts inspected.
For the recent wall-hung boilers, largely yes: both brands belong to the same group and use the same electronics.
No. Oil boilers have a burner with its own control box and show faults differently. Our engineers repair them too.
The flow temperature is rising too quickly, usually because water is not circulating well. The boiler waits before starting again.
Note it and call us. Repeated lockouts point to a fault that needs a diagnosis, not to more restarts.
Yes. If your De Dietrich is no longer worth repairing, we visit and give you a free quote for a boiler or a heat pump.
Call us or book online: a heating engineer comes to your home with his measuring equipment.