Saunier Duval Themafast F 24 E Air Pressure Switch Ref. S5744000
The Saunier Duval Themafast F 24 E air pressure switch controls the air pressure in the boiler and allows for its proper operation. When this part fails, it can prevent the boiler from starting or cause it to lock out, even if the pressure is correct, and the error 02: Flow/Air draft fault may occur. This pressure switch is compatible with several models, such as the Isofast F 28 E and the Isofast F 28 E1, among others. It is recommended to replace it if you experience starting issues or lockouts in the boiler.
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 tries to ignite, the fan spins, but the burner does not start and gets locked.
Cause: The air pressure switch does not detect the depression generated by the fan, which causes it to cut off the gas for safety.
Check that the silicone tubes connecting the pressure switch to the fan and the duct are not disconnected, bent, or filled with water.
- 02
The boiler works well almost all the time, but it gets blocked with strong winds or bad weather.
Cause: The air pressure switch may incorrectly interpret the wind pressure in the flue duct as a fault.
Check the condition and output of the flue duct: a blocked grille or a poorly installed section can cause the same symptoms.
- 03
Intermittent lockouts without apparent reason, especially during the first starts of the day.
Cause: Condensation in the pressure switch connection tubes can mimic an intermittent fault.
Disconnect and carefully blow through the silicone tubes of the pressure switch to ensure they are free of water and obstructions.
- 04
The extractor makes a strange noise or spins slower than normal before the fault occurs.
Cause: If the extractor does not reach the necessary revolutions, the pressure switch is functioning correctly by blocking the ignition.
Listen to and observe the fan during an ignition attempt: if it struggles to turn or makes noise, first check the fan.
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.
- Part code
- 605.99523
- Switching pressure
- 54/46 Pa
- Contacts
- 1(0.5) A / 250V~
- Manufacturer's internal code
- 4000115830
- Batch code
- LXKBFD
- Manufacturing date
- 15/03
Frequently asked questions about the pressure switch S5744000
Is the air pressure switch Saunier Duval Themafast F 24 E Ref. S5744000 for water or air?
At what pressure does the pressure switch Ref. S5744000 switch?
Is this pressure switch compatible with the Isofast F 28 E boiler?
How many models are compatible with the pressure switch PCTF24E?
What fault code is documented for this pressure switch?
Spare parts related to Saunier Duval Isofast
