Saunier Duval Isofast F 35 E Air Pressure Switch - Code 605.99534
When you turn on the heating, the air pressure switch Saunier Duval Isofast F 35 E - 605.99534 is responsible for monitoring the air pressure and authorizing the operation of the boiler. If this part fails, you will notice that the boiler does not start or gets locked, even if the pressure is adequate, and the fault code 02: Air flow safety may appear. This pressure switch is compatible with several models, such as those from the Isofast, Isomax, Isotwin ranges, among others. It is advisable to replace it when these symptoms occur to avoid problems in the heating system.
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 a fault warning for flue or smoke evacuation appears on the display.
Cause: The pressure switch does not close the safety circuit because it does not detect the minimum depression required to allow the gas to flow.
Check that the fan rotates freely and without strange noises; if it is slow or makes noise, the problem may be with the fan and not with the pressure switch.
- 02
The fan starts and sounds normal, but the boiler interrupts the process before igniting the burner.
Cause: The switching of the pressure switch is what allows the ignition; if it does not change position, the control board understands that there is no proper extraction.
Turn off the power and check the silicone tubes of the pressure switch: make sure they are not cracked, punctured, or filled with condensation.
- 03
The fault mainly occurs on cold or humid days and then disappears on its own.
Cause: Condensation in the connection pipes can distort the pressure reading without the pressure switch actually being damaged.
Bleed and dry the connection pipes before considering that the replacement of the pressure switch is correct.
- 04
The boiler is locked and does not respond to any attempts to reset.
Cause: A pressure switch with a stuck or damaged contact prevents the control board from receiving the correct flue signal.
With the boiler disconnected, measure the continuity of the pressure switch with a multimeter in its two positions before discarding it.
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
- 4 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~
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval F 35 E H-MOD Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the pressure switch S5744100
What code should the pressure switch of my Isofast F 35 E have?
Is this pressure switch suitable for a Saunier Duval Themafast F 30 E?
At what pressure does the pressure switch of the Isofast F 35 E switch?
Spare parts related to Saunier Duval Themafast
