Saunier Duval Isofast C 35 E1 Display Module Ref. 05721000
The Saunier Duval Isofast C 35 E1 Display Module is a control PCB that manages the ignition, burner modulation, pump, and safety features of the boiler. When it fails, the boiler may not start, become locked, or exhibit erratic operation. Users may notice faults such as F12: No signal from the user interface, F18: User interface failure, or F13: Main printed circuit board failure. This module is compatible with boilers from the Isofast range, including models such as C 28 E, C 35 E, and others. It is replaced when these symptoms or faults 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 rear casing of the display module is cracked or broken.
Cause: Plastic deteriorates with heat and impacts when disassembling the module for inspections.
Check if the break only affects the casing and not the internal PCB before ordering the part.
- 02
The tabs or clips that hold the module to the boiler are broken and the cover does not stay in place.
Cause: The plastic anchors break when opening and closing the module repeatedly over time.
Check if you can temporarily hold the cover to confirm that the issue is only with the fastening before purchasing the complete casing.
- 03
The display module does not close properly, leaving a gap through which dust or moisture can enter.
Cause: A deformed casing or one with broken clips does not fit properly with the rest of the module.
Measure the reference and exact model of your boiler before installing it, to ensure that the front frame fits well in the new casing.
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
Does the display module ref. 05721000 work for the Saunier Duval Isofast C 35 E1?
Is this module compatible with the Saunier Duval Isomax F 28 E2?
How do I check that this module ref. 05721000 is the same as the one installed in my boiler?
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