Saunier Duval Isofast F35 E1 Air Pressure Switch - Code 605.99534
The Saunier Duval Isofast F35 E1 air pressure switch is a device that controls the air pressure in the boiler. Its function is to ensure that the pressure is adequate to allow the boiler to operate. When it fails, you may notice that the boiler does not start or gets locked, and it may display the fault code 02: Air flow safety. This pressure switch is compatible with several boilers from the Isofast range, as well as with models from the Isomax, Isotwin, Isosplit, Themafast, Thema, Themaplus, Themaclassic, Opalia, and Opaliafast ranges. It is recommended to replace the pressure switch when it shows faults in starting or system locking.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S5744100
Pressure switch with reference S5744100. 21 verified compatibilities: F 30 E H-MOD and F 35 E1.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval F 30 E H-MOD | Isofast | Contrasted |
| Saunier Duval F 35 E1 | Isofast | Contrasted |
| Saunier Duval F 35 E H-MOD | Isofast | Contrasted |
| Saunier Duval F 28 E2 | Isomax | Contrasted |
| Saunier Duval F 28 EA | Isotwin | Contrasted |
| Saunier Duval F 30 E H-MOD | Isotwin | Contrasted |
| Saunier Duval F 30 E | Isosplit | Contrasted |
| Saunier Duval F 35 E | Isosplit | Contrasted |
| Saunier Duval F 35 E H-MOD | Isosplit | Contrasted |
| Saunier Duval F 25 E | Themafast | Contrasted |
| Saunier Duval F 25 E H-MOD | Themafast | Contrasted |
| Saunier Duval F 30 E | Themafast | Contrasted |
| Saunier Duval F 30 E H-MOD | Themafast | Contrasted |
| Saunier Duval F 25 E | Thema | Contrasted |
| Saunier Duval F 25 E STL | Thema | Contrasted |
| Saunier Duval F AS 25 E | Thema | Contrasted |
| Saunier Duval F 25 E | Themaplus | Contrasted |
| Saunier Duval F 30 E | Themaplus | Contrasted |
| Saunier Duval F AS 30 E | Themaclassic | Contrasted |
| Saunier Duval F 17 E | Opalia | Contrasted |
| Saunier Duval F 17 E | Opaliafast | 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. S5744100 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 S5744100. 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 S5744100 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 does not ignite and the display shows a fault related to the flue or smoke evacuation.
Cause: The pressure switch does not allow ignition because it does not detect the necessary negative pressure in the duct.
Before changing it, check that the flue pipe has no visible obstructions at the exterior outlet.
- 02
The extractor can be heard starting, but the burner does not ignite at any time.
Cause: Without the pressure switch signal, the control board does not allow the gas to flow even though the fan is functioning correctly.
Check the condition of the silicone tubes: cracks, folds, or disconnections can cause the same symptom as a faulty pressure switch.
- 03
The boiler only occasionally locks out, without a clear pattern.
Cause: A pressure switch with a worn contact can switch irregularly due to small pressure variations.
Check if the fault coincides with changes in wind or rain, which affect the pressure in the duct.
- 04
The boiler is locked and does not respond to reset attempts from the control.
Cause: If the pressure switch contact remains open, the control board never receives the flue validation it needs.
With the boiler turned off, use a multimeter to check if the pressure switch activates when applying a slight suction to the tube.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 02 | Air flow safety. | The air pressure switch S5744100 does not switch when the fan starts or does not detect the depression due to obstruction in tubes/venturi; check with a multimeter or manometer that the pressure switch changes state with the fan running and inspect tubes and 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 S5744100
- Catalogue reference
- S5744100
- Brand
- Saunier Duval
- Type of part
- Pressure switches
- Units in stock
- 5 units
- 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.
- Part code
- 605.99534
- Set pressure (switching)
- 59/51 Pa
- Contact (current / voltage)
- 1(0.5) A / 250 V~
Frequently asked questions about the pressure switch S5744100
Is this pressure switch suitable for a Saunier Duval Isofast F 35 E1?
At what pressure does the pressure switch of the Isofast F 35 E1 switch?
When should this pressure switch be replaced in the Isofast F 35 E1?
What electrical contact does the pressure switch of the Isofast F 35 E1 accept?
Spare parts related to Saunier Duval Themafast
