Saunier Duval Isofast 21 Condens F30 PCB Ref. 0020105958
If your boiler does not start, locks out, or behaves erratically, you may need the Saunier Duval Isofast 21 Condens control board Ref. 0020105958. This control PCB manages the ignition, burner modulation, pump, and safety features of the boiler. If it fails, you may see the fault code F.70, which indicates an invalid boiler identification and lack of communication with the board. It is compatible with the Isofast 21 Condens model, among other boilers in the same range. It is recommended to replace it when the mentioned symptoms occur.
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Consult via WhatsAppSaunier Duval boilers compatible with reference 0020105958
PCB with reference 0020105958. A proven compatibility: Isofast 21 Condens.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isofast 21 Condens | Isofast 21 Condens | 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 the ref. 0020105958 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 0020105958. If it is not visible, do not identify the part by 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 0020105958 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 and the display is off, with no indicators.
Cause: The PCB does not receive or distribute power to the other components.
Check the fuse on the PCB and verify that there is incoming power before considering it faulty.
- 02
A fixed fault code appears on the screen and the boiler does not start even after resetting.
Cause: The PCB prevents ignition by detecting an incorrect signal from a sensor or actuator.
Note the exact code and check the indicated component, such as the sensor or the pressure switch, before replacing the PCB.
- 03
The remote control or the panel are not responding, but the boiler continues to operate on its own.
Cause: There is usually a fault in the communication between the display and the PCB, not in the control logic.
Check the flat connector or the cable that connects the display and the PCB before replacing either of the two.
- 04
The boiler turns on and off by itself without a visible pattern or fault code.
Cause: A relay or a solder joint on the PCB degrades with heat and fails intermittently.
Check for any signs of moisture stains or corrosion on the control board casing before replacing it.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.70 | Invalid boiler identification. | It usually appears when the screen/interface and the main PCB are replaced simultaneously and the appliance's code/variant is not reconfigured; the interface remains 'unrecognized'. Verify by entering technical mode to adjust the product code and, if it persists, try with another screen/interface or check the resistance/power coding. |
| with | There is no communication with the PCB (screen ↔ electronics communication). | The interface/display board loses the data bus connection with the main PCB (fault of the interface itself or its connection/power supply). Check voltages and connectors between the display and the PCB, continuity of the harness, and, if applicable, temporarily replace the interface to rule out the fault. |
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 PCB 0020105958.
- Catalogue reference
- 0020105958
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 1 unit
- 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 Isofast 21 Condens Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the PCB 0020105958
For which boiler is the Saunier Duval Isofast 21 Condens F30 electronic PCB Ref. 0020105958 compatible?
How many models are compatible with this PCB?
What fault code is documented for this PCB?
What is the reference for this PCB?
What fault symptoms can the fault code F.70 indicate?
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