Display and Keyboard Module Saunier Duval Isofast C24EV A F35E1 / Isomax C-F28E
The Saunier Duval Isofast C24EV to F35E1 / Isomax C-F28E display and keyboard module is a control PCB that manages the ignition, burner modulation, pump, and safety features of the boiler. When faults occur, the boiler may fail to start, lock out, or operate erratically, displaying fault codes such as F12, F18, or F13. This module is compatible with several boilers in the Isofast range, such as models C 28 E, C 35 E, and F 35 E, among others, as well as in the Isomax range, like the C 28 E and F 28 E. It should be replaced when these malfunction symptoms are detected.
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 screen goes completely black, but the boiler continues to heat and provide hot water.
Cause: The display module is a separate board from the power board: if it fails, the display is lost but not necessarily the operation.
Check that hot water and heating are working before replacing the part: if the boiler operates without a display, the fault is in the module.
- 02
Some buttons respond while others do not, or they need to be pressed several times to work.
Cause: The keyboard is a membrane type and loses contact over time and humidity; not all traces fail at the same time.
Clean the surface of the buttons and check that the flat connector between the module and the boiler cable is properly fitted before replacing the part.
- 03
The screen flickers, turns off and on by itself, or shows stripes.
Cause: A poor connection in the connector or flat cable between the module and the main PCB causes intermittent power cuts to the display.
Turn off the boiler, disconnect and reconnect the flat connector of the module, and check if the flashing disappears.
- 04
The fault code cannot be seen nor can the boiler lock be reset from the control panel.
Cause: The keyboard is the only point of interaction with the control unit; if it does not respond, it is not possible to navigate the menu or confirm a reset.
Cut the main power to the boiler for 30 seconds and then restore power: if the lock resets itself, the fault points to the control panel and not to an underlying fault.
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
- 1-2 business days
- 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 screen and keyboard module compatible with a Saunier Duval Isofast C35E1?
Is this module compatible with the Saunier Duval Isomax C28E?
Spare parts related to Saunier Duval Isofast
