
Saunier Duval Display Module Keyboard Isofast F28E Ref. 05721000
When you turn on the hot water tap or activate the heating, the Saunier Duval Isofast F28E Display Module is responsible for managing the ignition, burner modulation, pump, and safety features of the boiler. If this part fails, you will notice that the boiler does not start, locks out, or operates erratically, potentially displaying fault codes such as F12, F18, or F13. It is compatible with several models from the Isofast and Isomax ranges, such as the F 28 E and C 28 E, among others. It is recommended to replace it when these issues or faults in operation occur.
VAT included
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 control panel does not turn on or shows nothing.
Cause: It could be a fault with the module or that it is not receiving power from the main PCB.
Check that the rear connector is properly seated in its housing before considering the module as faulty.
- 02
The keyboard buttons are not responding, even though they were working normally before.
Cause: The keyboard is a membrane that can lose continuity due to wear, moisture, or accumulated dirt.
Carefully clean the surface of the keyboard and try again before replacing it; sometimes, it is only necessary to remove dust or grease.
- 03
The boiler cannot be programmed or adjusted from the panel, although it continues to provide service.
Cause: This module controls the programming and parameter adjustment; if it fails, manual control is lost even though the boiler continues to operate with the previous values.
Note if the boiler maintains the last programmed setting (indicates that the main PCB is functioning) before changing only the module.
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.












