Saunier Duval ThemaClassic F24 E Air Pressure Switch - Ref. S1008900 (605.99561)
Air pressure switch that checks the correct operation of the extractor/fan before allowing the burner to ignite. If it does not detect the switching pressure within the set range, the boiler locks out for safety. It is replaced when the burner does not start even though the extractor is operating normally, or the contact does not switch.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S1008900
Pressure switch with reference S1008900. Seven confirmed compatibilities: ThemaClassic F24 E and ThemaClassic F25 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval ThemaClassic F24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F AS 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F AS 25 E | ThemaClassic | Contrasted |
| Saunier Duval Thematek SF 24 E | Thematek | Contrasted |
| Saunier Duval Thematek F 24 E | Thematek | Contrasted |
| Saunier Duval Combitek F24 E | Combitek | 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. S1008900 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 S1008900. 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 S1008900 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 turns on the fan but stops before igniting, without releasing any gas.
Cause: The pressure switch does not close the contact that allows the gas to flow, so the control board cuts the cycle before ignition.
Check that the silicone tube between the pressure switch and the flue is not bent, broken, or disconnected.
- 02
The display gets stuck in the pre-purge phase, with the fan running and never moving on to ignition.
Cause: The pressure differential generated by the extractor does not reach the pressure switch contact, or the internal spring is stuck.
Check that the fan rotates smoothly and without unusual noises before assuming that the pressure switch is faulty.
- 03
The boiler tries to ignite several times in a row and ends up showing a ventilation fault.
Cause: A pressure switch that switches intermittently causes the control unit not to receive a stable signal and to repeat the attempt.
Check the electrical connections of the pressure switch, as they can sometimes come loose or oxidize and give an irregular signal.
- 04
You have cleaned the flue and the boiler still won't ignite.
Cause: If the pressure switch is already damaged, cleaning the flue does not solve the blockage because the contact still does not switch.
With the extractor running, use a multimeter to check if the pressure switch contact closes when reaching the operating regime.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F2 | Air deficiency safety (Themaclassic F): flue gas intake/exhaust fault. | The air pressure switch does not switch (does not close) when the fan starts due to lack of depression, fatigued diaphragm, or blocked inlets/tubes; check continuity at its terminals during the pre-purge and inspect tubes to the fan and flue duct. |
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 the Saunier Duval pressure switch S1008900
- Catalogue reference
- S1008900
- 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.
- Model code
- 605.99561
- Set (switching/reset)
- 80/68 Pa
- Switching value of the contact
- 1(0.5)/250~
- Long code (likely internal ref. Saunier Duval/Vaillant)
- 4000121232
- Batch code
- UUDEEC
- Date (week/year)
- 44/02
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval ThemaClassic F AS 25 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the pressure switch S1008900
Is the air pressure switch Saunier Duval ThemaClassic F24 E compatible with a Glow-worm CI 24?
Is it an air pressure switch or a flue gas pressure switch that the ThemaClassic F AS 25 E has?
What air pressure is the pressure switch of the Combitek F24 E set to?
How many models are compatible with the Saunier Duval ThemaClassic F24 E air pressure switch?
What fault code is documented for the air pressure switch PTF24E?
Spare parts related to Saunier Duval ThemaClassic
