3-Way Valve Saunier Duval ThemaClassic C25E Ref. S1020800

Saunier Duval boilers compatible with reference S1020800

3-way valve with reference S1020800. 16 verified compatibilities: ThemaClassic F 24 E and ThemaClassic C 24 E.

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. S1020800 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 S1020800. 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 S1020800 three-way valve resolves.

The 3-way valve diverts water between heating and domestic hot water. These are the typical symptoms and what to do:

Common symptoms and faults

• 01

  There is no hot water coming from the tap even though the radiators are heating well, or vice versa.

  Cause: The valve does not switch to the correct circuit.

  Turn off the heating and request only hot water to see if it reacts: this way you can determine if it is a fault with the gas valve or a priority issue.

• 02

  The boiler does not switch correctly between heating and domestic hot water.

  Cause: The mechanism gets stuck due to scale or wear of the gas valve.

  If you can access the valve stem, try moving it by hand when cold to check if it is stuck.

• 03

  There is accumulated water or a constant drip in the area of the gas valve.

  Cause: The internal gaskets wear out over time and stop sealing between the channels.

  Before changing the part, dry the area and check if the drip appears only in heating, only in domestic hot water, or in both: this will help you determine if it is the gas valve or a nearby fitting.

• 04

  The tap water never reaches the right temperature, it stays lukewarm.

  Cause: A small amount of flow is leaking into the other circuit because the shutter does not close properly.

  Compare the temperature with the radiators off and on: if it improves significantly with the radiators off, the valve is allowing water to pass through.

Fault codes from Saunier Duval that this spare part resolves.

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 S1020800 three-way valve.

Catalogue reference

S1020800

Brand

Saunier Duval

Type of part

3-way valves

Units in stock

1 unit

Status

Refurbished

Warranty

1 year

Shipping

1-2 business days

Return

14 days

Manuals and technical documentation

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

• Saunier Duval Themaclassic F 25 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.