Air Pressure Switch Boiler Themaclassic F25E / Thematek SF24E - 605.99561
Air pressure switch for boilers in the Themaclassic series (F AS 24E, F AS 25E, F24E, F25E) and Thematek SF24E. It controls the air pressure in the combustion circuit and allows ignition only if the fan extracts correctly. It is replaced when the boiler does not start or shows a ventilation fault. Component code 605.99561, opening/closing setting 80/60 Pa.
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 gets locked before igniting and shows a ventilation fault.
Cause: The pressure switch does not indicate to the control board that there is sufficient draft in the duct, even though the extractor is working properly.
Check that the flue duct is not obstructed by leaves, nests, or accumulated condensation.
- 02
The fan starts correctly, but the burner never ignites.
Cause: The pressure switch must close the contact to allow the gas valve to activate; if it doesn't, the gas does not reach the burner.
Cut and reconnect the silicone tubes of the pressure switch: they sometimes come loose due to vibrations.
- 03
The fault occurs mainly when there is strong wind or rain.
Cause: A pressure switch that is at the limit of its travel is more sensitive to external pressure changes that come through the flue.
Note if the blockage occurs under windy conditions before deciding whether to replace the part.
- 04
The boiler intermittently locks out: sometimes it ignites and sometimes it doesn't, without a clear pattern.
Cause: A worn or dirty internal contact can operate irregularly depending on the position of the diaphragm.
Reset the lock several times in a row and note if the fault repeats in the same way or varies with each attempt.
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.
- Component code
- 605.99561
- Switching setpoint (open/close)
- 80/60 Pa
- Electrical characteristics of the contact
- 1(0.5) A / 250 V~
- Batch code
- EKYAID
- Long reference
- 4000121232
- Date (week/year)
- 08/03
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 pressure switch from the Themaclassic F25E compatible with the Thematek SF24E?
What code should I check on the pressure switch of my boiler?
At what pressure does the pressure switch of the boiler open and close?
When should the pressure switch of the Themaclassic F25E be replaced?
What is the reference for the compatible air pressure switch?
How many models are compatible with this pressure switch?
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