
Saunier Duval Thema NOx F25 Air Pressure Switch - Ref. 0020124897 / 0020111755
Differential air pressure switch for Saunier Duval boilers Thema Condens 25-A, Thema NOx F25, and Themafast NOx F25/F30. Set to 59/24 Pa for opening/closing and electrical load 1(0.5)A at 250V~, according to the label. It has the code 605.99882 engraved; the catalog reference 0020124897 is equivalent to 0020111755 printed on the part. It is replaced when the boiler locks due to an air pressure switch fault.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 0020124897
Pressure switch with reference 0020124897. Two confirmed compatibilities: Thema NOX F25 and Themafast NOX F30.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Thema NOx F25 | Thema NOX / Themafast NOX | Contrasted |
| Saunier Duval Themafast NOx F30 | Thema NOX / Themafast NOX | 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. 0020124897 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 0020124897. 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 pressure switch 0020124897 resolves.
The pressure switch controls the air or water pressure to authorize operation. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler is locking out and the display shows a fault or blockage of the pressure switch.
Cause: This pressure switch compares the pressure between two connections and, if the difference does not reach the required value, it does not allow the ignition.
Make sure that both pressure connections are properly connected and in the correct order; if they are swapped, it can cause the same fault as a broken part.
- 02
The extractor works correctly, but the burner never ignites.
Cause: If the pressure difference does not reach the necessary point, the electronics do not receive the signal to ignite, even though the fan is working properly.
Check that both silicone tubes are free of obstructions, breaks, or kinks before replacing the part.
- 03
The fault is intermittent: some days it starts without issues and other days it gets stuck.
Cause: A contact that activates the system near its set point may fail due to small variations in pressure or dirt in the mechanism.
Carefully clean the pressure connections and make sure there is no condensation accumulated in the pipes.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F2 | Safety lack of draft (SRC) or pressure switch. | The air pressure switch does not switch when the fan starts due to lack of vacuum or internal fault; it can be checked by measuring continuity at its terminals during start-up and inspecting/cleaning tubes and venturi. |
| F33 | Air flow fault. | The air pressure switch remains open and does not confirm flow/depression, blocking ignition; check with a multimeter if it changes state when the fan is activated and inspect the condition of hoses and venturi connections. |
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.
Datasheet for Saunier Duval pressure switch 0020124897
- Catalogue reference
- 0020124897
- Brand
- Saunier Duval
- Type of part
- Pressure switches
- Units in stock
- 1 unit
- 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.
- Pressure differential (open/close)
- 59/24 Pa
- Electric charge
- 1(0.5)A / 250V~
- Manufacturer code
- 605.99882
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval Thema Nox F25 Manual (PDF)Document © Saunier Duval, provided as a technical reference.












