Lacroix SYMSI7.0 PCB Saunier Duval Isofast F35E H-MOD
The control PCB governs the ignition, burner modulation, pump, and safety features of the boiler. When it fails, the boiler may not start, lock out, or exhibit erratic behavior, displaying fault codes such as 13: Main printed circuit failure, 12: No user interface signal, or 20: Communication defect. This PCB is compatible with Saunier Duval Isofast F30 E H-MOD and Isofast F35 E H-MOD boilers, among others. It should be replaced when the mentioned symptoms or associated fault codes occur.
VAT included
Consult via WhatsAppSaunier 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
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 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 and faults that the PCB S1020000 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 doesn't light up any indicator, it seems completely off.
Cause: A fault in the power supply to the PCB prevents it from receiving current to operate.
Check the input voltage to the boiler and the main fuse before considering the PCB as faulty.
- 02
A fault code appears on the display that disappears when the boiler is turned off and on, but returns after a while.
Cause: A PCB with damaged solder joints can cause intermittent faults without any actual mechanical failure.
Note the exact code and the point in the cycle when it appears before deciding on the change.
- 03
The boiler control loses connection and shows a communication fault.
Cause: The PCB manages communication with the control and can fail at that stage.
Check the connection of the control bus on the terminal block of the PCB before replacing it.
- 04
The boiler starts but stops by itself after a few seconds, in a loop.
Cause: If the PCB does not correctly process the signals from the safety sensors, it will cut off the ignition cycle as a precaution.
Check the status of the safety sensors and their wiring before blaming the PCB.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 13 | Main PCB fault | Fault in the main PCB (PCB SYMSI 7.0), e.g. circuit/EEPROM failure, preventing control; check power supplies and connectors and, if necessary, confirm by replacing with a compatible PCB in good condition. |
| 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
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 3 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- 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.
- Control platform
- SYMSI7.0
- Barcode code
- SP.284A
- Batch number
- 137178
- Lacroix is the manufacturer of the electronic component, not the boiler: Saunier Duval is the brand of the boiler.
Frequently asked questions about the PCB S1020000
Who actually manufactures the SYMSI7.0 PCB of the Isofast F35E H-MOD, Lacroix or Saunier Duval?
What control platform does the Lacroix SYMSI7.0 PCB use?
In which Saunier Duval models can I install the Lacroix SYMSI7.0 PCB?
How many models are compatible with the Lacroix SYMSI7.0 PCB?
What fault codes are documented for the Lacroix SYMSI7.0 PCB?
What is the reference for the Lacroix PCB for the Isofast F35E H-MOD?
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