Water Pressure Sensor Saunier Duval Isofast F 35 E1 - Ref. S5720500
The water pressure switch Saunier Duval Isofast F 35 E1 is a sensor that measures the pressure of the circuit and sends the information to the boiler's PCB. When it fails, incorrect readings and lockouts due to false low pressure can occur, which could disrupt normal operation. This component is installed in boilers from the Isofast range, such as the F 35 E model, as well as in other models from the ThemaClassic range, among others. It is recommended to replace it upon the appearance of the fault code F9: Water pressure detector failure.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S5720500
Pressure sensor with reference S5720500. Six confirmed compatibilities: F 25 E and C 25 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval F 25 E | ThemaClassic | Contrasted |
| Saunier Duval C 25 E | ThemaClassic | Contrasted |
| Saunier Duval F 30 E | ThemaClassic | Contrasted |
| Saunier Duval C 24 E1 | ThemaClassic | Contrasted |
| Saunier Duval F 24 E1 | ThemaClassic | Contrasted |
| Saunier Duval F 35 E | 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. S5720500 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 S5720500. 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 sensor S5720500 resolves.
The pressure sensor measures the water pressure for the electronics. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
A pressure fault indicator or fault code appears on the display, even though the circuit is properly filled.
Cause: The sensor sends an incorrect reading and the PCB locks the boiler for safety.
Measure the pressure displayed on the screen with an external manometer before changing the sensor.
- 02
The boiler locks up as soon as you try to start it, without the burner igniting.
Cause: The PCB requires a valid pressure signal to allow ignition, and it is not receiving it.
Disconnect and reconnect the 4-wire connector of the sensor; a poor connection can cause the same fault.
- 03
The pressure value on the display does not change even when you fill the circuit with the filling key.
Cause: The sensor has stopped generating the signal proportional to the pressure and remains fixed at a value.
Fill the circuit slowly and check if the pressure number rises on the display; if it doesn't move, the signal is not reaching.
- 04
The boiler works normally at times and other times it stops by itself showing a pressure fault.
Cause: An intermittent contact in the wiring of the sensor causes the signal to be lost sporadically.
Check the cable route of the sensor for bends or abrasions before considering the part faulty.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F9 | Water pressure sensor fault. | The pressure transducer S5720500 delivers an absent/out-of-range signal or does not reach the PCB, the electronics interpret an abnormal pressure and lock with F9; verify by measuring the sensor signal and the harness/wiring and comparing with an external manometer. |
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.
Data sheet for Saunier Duval pressure sensor S5720500
- Catalogue reference
- S5720500
- Brand
- Saunier Duval
- Type of part
- Pressure sensors
- 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.
- Pressure range
- 0/4.5 bar
- Electrical output
- 1/4 Vdc (literal reading from the label)
- power supply
- 5 Vdc
- Protection class
- T70 / CLASS III
- pinout
- 1: 0V | 2: +Vcc | 3: NC | 4: OUT
- Part code
- PSN0001A (final suffix cut off in the photos, see notices)
- Manufacturing origin
- MADE IN FRANCE
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval F 25 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the pressure sensor S5720500
What function does this pressure sensor Ref. S5720500 perform in the Isofast F 35 E1?
Is this sensor compatible with the Saunier Duval ThemaClassic F 24 E1?
What pressure range does the sensor Ref. S5720500 measure?
What voltage does this pressure sensor from Isofast operate on?
How many models are compatible with the pressure sensor Ref. S5720500?
What fault code is documented for this pressure sensor?
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