Lacroix PCB SY-MSI-7.0 For Saunier Duval Isofast F 35 E H-MOD
Control PCB manufactured by Lacroix in Poland, model SY-MSI-7.0, confirmed by the silkscreen and the manufacturer's label. It is the main board that governs the operation of the boiler. Compatible with several models of the Saunier Duval Isofast, Isotwin, Themaclassic, and Themafast range. Replacement requires first confirming the fault of the part through technical diagnosis, even when the control board fails and the boiler stops responding.
- Type of part
- PCBs (control boards)
- Status
- Refurbished
- Catalogue reference
- S1020000
- Warranty
- 1 year
Saunier Duval boilers compatible with reference S1020000
PCB with reference S1020000. Two confirmed compatibilities: Isofast F30 E H-MOD and Isofast F35 E H-MOD.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isofast F30 E H-MOD | Isofast | Contrasted |
| Saunier Duval Isofast F35 E H-MOD | Isofast | 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. S1020000 is the part for your boiler
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference S1020000. 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 that require diagnosis on the PCB S1020000
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 start, as if it is not receiving the ignition command.
Cause: The control board manages the entire startup process; if it fails, no other component receives the command to start up.
Check that power is reaching the boiler and that the input fuse is not blown: a power failure mimics a dead PCB.
- 02
The control or display is not responding and does not seem to communicate with the boiler.
Cause: The PCB centralizes communication with the control; if its communication circuit fails, the control becomes unresponsive even if it is functioning properly.
Try another remote control, if possible, or check the bus wiring between the remote control and the boiler before declaring the PCB faulty.
- 03
A fault code from the PCB appears without a clear cause, with no gas, water, or pressure fault.
Cause: When the code points to the control electronics and mechanical causes have been ruled out, the fault is usually in the PCB.
Note the exact fault code and reset the boiler once: if the error reappears immediately without a mechanical reason, it points to the PCB.
- 04
The boiler suddenly stops responding, without any prior gradual symptoms.
Cause: A fault in a component of the motherboard, such as the power stage, can render it inoperative suddenly.
Before replacing the PCB, check that the residual current device or the circuit breaker of the home's electrical installation has not tripped.
Fault codes Saunier Duval that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| 13 | Main PCB fault | This symptom may be related to the part, but it does not confirm that it is faulty. A technician must check the equipment and its inspection according to the manual before deciding on a repair or replacement. |
| 12 | No signal user interface | Loss of communication between the user interface and the main board; a fault in the PCB can prevent sending/receiving data. Check the harness/wiring between the interface and the board, and if there is continuity and correct voltages, suspect the PCB. |
| 20 | Communication fault | Incompatibility/communication defect between interface and main PCB (e.g. incorrect product code/firmware or defective PCB). Check product coding and interface compatibility; if it persists, inspect/replace 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 S1020000 PCB.
- Catalogue reference
- S1020000
- Uniclima internal SKU
- CECIF35MOD
- 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
Part data and available documentation
Contrast the label codes, PCB, and revision with the installed part; they are not necessarily equivalent references.
- Model / control platform
- SY-MSI-7.0
- PCB manufacturer
- Lacroix (Poland)
- Flammability marking of the PCB
- SUNG WEI 06V0-A
Frequently asked questions about the PCB S1020000
Is the Lacroix SY-MSI-7.0 PCB for the Saunier Duval Isofast F 35 E H-MOD original from Saunier Duval?
Is this Lacroix SY-MSI-7.0 PCB also suitable for the Saunier Duval Isofast F 30 E H-MOD?
What fault in the Saunier Duval Isofast F 35 E H-MOD does this PCB fix?
How many models are compatible with the Lacroix SY-MSI-7.0 PCB?
What fault codes are documented for the Lacroix SY-MSI-7.0 PCB?
Where can I find the reference for this PCB?
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