Saunier Duval Display Module Control Isofast F 35 F Ref. 05721000
The control PCB governs the ignition, burner modulation, pump, and safety features of the boiler. The Saunier Duval Display Module Mando Isofast F 35 F, with reference 05721000, is essential for the operation of several models. If it fails, you will notice that the boiler does not start, locks out, or exhibits erratic behavior, potentially displaying faults such as F12, F18, or F13. This part is compatible with Isofast boilers, such as the C 28 E, C 35 E, and F 28 E, among others. It is recommended to replace it upon detecting these symptoms to avoid further issues.
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Consult via WhatsAppSaunier Duval boilers compatible with reference 05721000
PCB with reference 05721000. 14 verified compatibilities: C 28 E and C 28 E1.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval C 28 E | Isofast | Contrasted |
| Saunier Duval C 28 E1 | Isofast | Contrasted |
| Saunier Duval C 28 E NOx | Isofast | Contrasted |
| Saunier Duval C 28 E1 NOx | Isofast | Contrasted |
| Saunier Duval C 35 E | Isofast | Contrasted |
| Saunier Duval C 35 E1 | Isofast | Contrasted |
| Saunier Duval F 28 E | Isofast | Contrasted |
| Saunier Duval F 28 E1 | Isofast | Contrasted |
| Saunier Duval F 35 E | Isofast | Contrasted |
| Saunier Duval F 35 E1 | Isofast | Contrasted |
| Saunier Duval C 28 E | Isomax | Contrasted |
| Saunier Duval C 28 E2 | Isomax | Contrasted |
| Saunier Duval F 28 E | Isomax | Contrasted |
| Saunier Duval F 28 E2 | Isomax | 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. 05721000 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 05721000. 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 05721000 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 does not ignite, neither a LED lights up nor does the fan start.
Cause: The module does not supply power to the other components because its internal power supply stage has failed.
Check that there is power in the house and that voltage is reaching the network connector of the module.
- 02
A fault code appears on the display and reappears after resetting.
Cause: The module is locked for safety after detecting an anomaly that does not resolve on its own.
Identify the exact code and first rule out the components it usually indicates, such as the sensor, the pressure switch, or the flame.
- 03
The boiler starts and shuts down repeatedly after a few seconds.
Cause: The module does not maintain the command to the gas valve long enough for the ignition to stabilize.
Check if the cut occurs at the same time after startup; a repeated pattern indicates a possible fault in the module.
- 04
There is no response from the thermostat or the control panel, even though the boiler is powered.
Cause: The communication between the module and the control has stopped working.
Check the bus cable connections between the control and the module before replacing the part.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F12 | No signal from the user interface | Yes — it points to this display/interface module or its connection cable with the main PCB. |
| F18 | User interface fault | Yes — it corresponds to this display/control board module. |
| F13 | Main PCB fault | No — that code is for the MAIN PCB (a different part), not for this display. |
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 05721000 PCB.
- Catalogue reference
- 05721000
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 5 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval F 28 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the PCB 05721000
Is this electronic module compatible with the Saunier Duval Isomax C 28 E2?
Spare parts related to Saunier Duval Isofast
