Saunier Duval Thelia 23 PCB Ref. 8/050149E
If your boiler does not start, locks out, or exhibits erratic behavior, you may need the Saunier Duval Thelia 23 PCB Ref. 8/050149E. This control board manages essential functions such as ignition, burner modulation, and the pump, ensuring the proper operation of the boiler. Users may notice issues such as fault code F.28, which indicates a start-up failure, or F.63, related to the EEPROM. This board is compatible with several models in the Thelia range, including the 23 (post-CE) and the 623, among others. It is recommended to replace it when the mentioned symptoms are detected.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 05712700
PCB with reference 05712700. Four confirmed compatibilities: 23 (post-CE) and 623.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval 23 (post-CE) | Thelia | Contrasted |
| Saunier Duval 623 | Thelia | Contrasted |
| Saunier Duval 623 CE | Thelia | Contrasted |
| Saunier Duval AS 23 (post-CE) | Thelia | Contrasted |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if ref. 05712700 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 05712700. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the PCB 05712700 resolves.
The PCB controls the ignition, modulation, and safety features of the boiler. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler ignites, starts the sequence, and halfway through the process it stops by itself for no apparent reason.
Cause: The PCB distributes its outputs across three different relays; if one gets stuck or opens prematurely, it cuts that circuit halfway through the sequence.
Look at which component stops receiving current just before the cut to identify which of the three relays is failing.
- 02
The same circuit always fails (for example, the domestic hot water) while the other two operate normally.
Cause: Each relay on the PCB controls a different output, so an isolated fault only affects that circuit.
Measure with the multimeter if voltage reaches the component of that circuit when it should be activated, before replacing the entire PCB.
- 03
The fuse on the PCB blows again as soon as it is replaced.
Cause: A fuse that keeps blowing usually indicates a short circuit on the PCB itself or in something connected to it.
Disconnect the components powered by the PCB one by one to see if the short circuit disappears before considering the board as lost.
- 04
The boiler does not start at all, with no indicators or display lit up.
Cause: If the input stage of the PCB fails, power does not reach the rest of the electronics.
Check the fuse and the mains voltage at the input connector of the PCB before replacing it.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.63 | EEPROM fault. | The EEPROM memory of the PCB is corrupted or unreadable; the self-diagnosis locks the equipment. Verify by measuring the power supplies of the PCB and, if the peripherals are correct, confirm by reprogramming/initializing or replacing the PCB. |
| F.64 | Fault in the electronics / NTC. | The analogue-to-digital converter or the measurement stage of the PCB misinterprets the NTCs (incoherent readings). Verify the actual resistances of the NTC at the board connector and the continuity of the harness; if they are correct and the fault persists, the PCB is faulty. |
| F.70 | Invalid product code (DSN). | After replacing the display and/or PCB, the DSN has not been recoded or there are missing/errors in the coding resistor; the board goes into lockout. Check the appliance code in the service menu and recode (d.93) or install the correct resistor/code. |
| F.61 | Gas valve control/activation fault. | The PCB driver does not deliver the appropriate signal/voltage to the gas valve (or detects it as short-circuited). Check the continuity of the harness and the command voltage/waveform at the valve terminals during the ignition attempt; if the valve and wiring are fine and there is no correct command, the cause is the PCB. |
| F.28 | Start-up fault: ignition failed. | If the ignition/control stage of the PCB fails (does not excite the spark transformer or does not switch the valve), the burner does not start and F.28 appears. Check the spark and control voltage to the transformer/valve; if gas, electrodes, and harnesses are OK and there is no excitation from the PCB, the cause is the PCB. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Saunier Duval 05712700 PCB.
- Catalogue reference
- 05712700
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 2 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- PCB code
- 8/050149E
- Additional code (MTLC)
- MTLC 9716
- Fuse
- 80 mA T
- Main relays
- ZETTLER AZ 696-1A-24DE, coil DC 24V, contacts AC 250V 8A (x3)
- Supply voltage
- 230 V
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval 23 Manual (post-CE) (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the PCB 05712700
Is the PCB Ref. 8/050149E compatible with the Thelia range?
What reference should I request for the PCB of the Thelia AS 23?
When should I replace the PCB in the Thelia boiler?
How many models are compatible with this PCB?
What fault codes are documented for this PCB?
What is the reference for the PCB for the Thelia range?
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