Saunier Duval Isomax F 28 E PCB Ref. 05724800
PCB for Saunier Duval Isomax and Isofast C/F 28 E and 35 E boilers. The actual manufacturer of the board is Saunier Duval; the integrated transformer is manufactured by Lacroix Poland (marked VDE), with reference No. SOFREL 03101231D003 and code 116844 4/50K 06 16. It has a fuse of 125 mAT/250V. It is replaced when the boiler's control electronics fail.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 05724800
PCB with reference 05724800. Eight confirmed compatibilities: C 28 E and C 28 E NOx.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval C 28 E | Isofast | Contrasted |
| Saunier Duval C 28 E NOx | Isofast | Contrasted |
| Saunier Duval F 28 E | Isofast | Contrasted |
| Saunier Duval C 35 E | Isofast | Contrasted |
| Saunier Duval F 35 E | Isofast | Contrasted |
| Saunier Duval C 24 E V | Isofast | Contrasted |
| Saunier Duval C 28 E | Isomax | Contrasted |
| Saunier Duval F 28 E | 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. 05724800 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 05724800. 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 05724800 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 or show any signs, as if it were completely without power.
Cause: The PCB has a protection fuse; if it blows, it cuts off the power to all the electronics even if the rest of the boiler is fine.
Locate the fuse on the PCB and check its continuity with a multimeter before replacing the entire board.
- 02
The boiler works for a while and then turns off by itself, without a clear fault code.
Cause: A transformer or power supply stage with an intermittent fault can cause the PCB to lose voltage temporarily.
Check that the connections to the transformer integrated on the PCB are not loose or oxidized before replacing it.
- 03
The display does not turn on, but a small buzzing or clicking sound can be heard when power is supplied.
Cause: That noise may come from a relay trying to activate without the rest of the PCB receiving sufficient voltage.
Check the mains voltage at the boiler socket and rule out an electrical installation issue before declaring the PCB faulty.
- 04
The boiler shows a fault code as soon as power is supplied, before attempting anything else.
Cause: A fault detected during the startup of the control board itself, for example in its internal power supply, is displayed before it attempts to initiate the ignition cycle.
Note the exact code that appears as soon as power is supplied, because that information narrows down whether the issue is with the PCB or an external component.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 13 | Main printed circuit board fault. | The main PCB is faulty. Check auxiliary voltages (5/12 VDC) and connectors of the PCB; if the power supply and wiring/UI are correct and the board does not deliver voltages or shows damage/continuous reset, replace the PCB. |
| 20 | Communication fault/incompatible interface with the main PCB. | The main PCB is incompatible or there is a communication failure with the user interface (coding/DSN or e‑Bus). Verify product code and compatibility UI↔PCB; if the fault persists with the correct UI, 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 05724800 PCB.
- Catalogue reference
- 05724800
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 1 unit
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- 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.
- Fuse
- 125 mAT / 250V
- Manufacturer of the transformer integrated into the PCB
- Lacroix Poland (marked VDE)
- Printed reference on the transformer (SOFREL)
- N.º SOFREL 03101231D003
- Code printed on the transformer
- 116844 4 / 50K 06 16
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 05724800
Who manufactures the PCB of the Isomax F 28 E, Ref. 05724800?
Why does the Lacroix or Sofrel brand appear in some photos of this PCB?
What fuse does the PCB 05724800 of the Isomax F 28 E use?
Is this PCB compatible with an Isofast F 35 E?
What code is engraved on the transformer of this PCB?
Spare parts related to Saunier Duval Isofast
