Domestic Hot Water Flow Sensor Saunier Duval Isomax F 28 E2

Saunier Duval boilers compatible with reference S5720200

Flow meter with reference S5720200. 33 confirmed compatibilities: ThemaClassic C24E and ThemaClassic C25E.

Proven compatibility

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. S5720200 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.

1. Find the reference printed on the installed part and check whether it matches the catalogue reference S5720200. If it is not visible, do not identify the part from its shape alone.
2. Check the full boiler model on its data plate and look for it in the model associations on this page.
3. Compare the connections and physical body with the original part before installation.
4. If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.

Symptoms and faults that the flow meter S5720200 resolves.

The flow meter detects the passage of water to activate the domestic hot water. These are the typical symptoms and what to do:

Common symptoms and faults

• 01

  When opening the hot water tap, the boiler does not start: it does not attempt to ignite the burner.

  Cause: The NTC thermistor does not detect the flow of water, so the PCB never receives the demand signal for domestic hot water.

  Open the tap fully and check that water is actually flowing before declaring the sensor faulty.

• 02

  Hot water comes out for a while and then suddenly cools down, even though the tap remains open.

  Cause: The accumulated scale on the thermistor distorts its reading, and the control unit interprets that water has stopped flowing.

  If the area has hard water, check for visible limescale on the 28 mm thread before replacing the sensor.

• 03

  The heating works well, but the hot water from the tap never starts.

  Cause: This part only operates in the domestic hot water circuit, so a fault here does not affect heating and vice versa.

  Check that the fault occurs in all the taps in the house and not just in one, to rule out an installation issue.

• 04

  The flow of hot water seems weaker than normal even though the pressure of the boiler is fine.

  Cause: An intermediate reading of the thermistor due to dirt can cause the control board to limit the ignition instead of allowing it to fully ignite.

  Measure the actual flow rate with a bucket and a stopwatch at the tap to rule out that the problem is in the installation.

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 the Saunier Duval S5720200 flow meter

Catalogue reference

S5720200

Brand

Saunier Duval

Type of part

Flow detectors

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.

Type of component and connections

Domestic hot water flow sensor, thermistor type (NTC), male thread 18 mm + female 28 mm

Manuals and technical documentation

Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.

• Saunier Duval Thematek S F24E Manual (PDF)Document © Saunier Duval, provided as a technical reference.