Saunier Duval Isofast Air Pressure Switch F28 E2 Ref. S5744000
When the heating system starts, the air pressure switch Saunier Duval Isofast F28 E2 is responsible for monitoring the air pressure, ensuring that everything operates correctly. If this component fails, you will notice that the boiler does not start or gets locked, even though the actual pressure is adequate, and the fault code 02: Flow/Air draft failure may appear. This pressure switch is compatible with models from the Isofast range, such as the Isofast F 28 E and the Isofast F 28 E1, among others. It is recommended to replace it in case of faults or lockouts during the boiler startup.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S5744000
Pressure switch with reference S5744000. Two confirmed compatibilities: Isofast F 28 E and Isofast F 28 E1.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isofast F 28 E | Isofast | Contrasted |
| Saunier Duval Isofast F 28 E1 | 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. S5744000 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 S5744000. 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 S5744000 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 spins, but it stops before the flame comes out.
Cause: The pressure switch does not close the contact even though the extractor generates air pressure, and the control board thinks there is not enough draft.
Check that the silicone tube between the pressure switch and the fan is not perforated, bent, or disconnected.
- 02
The display shows a fault code for the fan or pressure switch, and it needs to be reset to try again.
Cause: It is the safety response of the control board when the pressure switch does not confirm the pressure during the pre-purge.
With the extractor running, measure with a multimeter if the pressure switch closes the contact before replacing it.
- 03
The extractor works well, but the burner does not start.
Cause: The pressure switch acts as a filter between the extractor and the ignition; if the diaphragm is damaged, it will not switch even if there is sufficient pressure.
Also check the flue duct for obstructions (blocked terminal, nest, ice) before replacing the part.
- 04
The fault mainly occurs with wind or on cold days, and sometimes the boiler ignites without any issues.
Cause: A pressure switch at the end of its useful life may fail intermittently depending on the resistance it encounters from the fan in the duct.
Note if the fault matches those conditions before considering the part as defective.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 02 | Airflow/flue fault (flue safety). | The air pressure switch does not switch when the fan starts (damaged diaphragm/contacts, obstructed intake tubes, or poor connection), so the PCB detects a lack of pressure drop and triggers the air fault; verify by measuring the continuity of the pressure switch (Pr terminals) with a multimeter during startup, and check the pressure and exhaust tubing. |
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 S5744000
- Catalogue reference
- S5744000
- Brand
- Saunier Duval
- Type of part
- Pressure switches
- Units in stock
- 7 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- 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.
- Switching pressure
- 54/46 Pa
- Electrical contacts
- 1(0.5) A / 250 V~
- Factory code (label)
- 605.99523
- Manufacturer's internal code
- 4000115830
- Batch code
- VMSADE
- Manufacturing date
- 03/04
- This part is identical, by factory code and internal code, to the one sold for the Isomax C28 E2 (SKU PIC28E2); only the batch and manufacturing date are different.
Frequently asked questions about the pressure switch S5744000
At what pressure does the pressure switch of the Saunier Duval Isofast F28 E2 (Ref. S5744000) switch?
Which models are compatible with the pressure switch Ref. S5744000?
What electrical contacts does the pressure switch of the Isofast F28 E2 have?
How many boiler models are compatible with the pressure switch PIF28E2?
What documented fault code corresponds to this pressure switch?
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