3-Way Valve Saunier Duval ThemaClassic C24E Ref. S1020800
The 3-way valve Saunier Duval ThemaClassic C24E Ref. S1020800 is a component that allows the switching of water between the heating circuit and the domestic hot water circuit. When it fails, you will notice that you have hot water but no heating, or vice versa, or both circuits may mix. This valve is compatible with several models in the ThemaClassic range, such as the ThemaClassic F 24 E and C 24 E, among others. It is important to replace it when you observe these symptoms or if the fault code F14 appears, which indicates a heating temperature above 95 °C.
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
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval ThemaClassic F 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 24 EV | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F 25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 25 EV | ThemaClassic | Contrasted |
| Saunier Duval Thematek F 24 E | Thematek | Contrasted |
| Saunier Duval Thematek C 24 E | Thematek | Contrasted |
| Saunier Duval Thematek C 24 EV | Thematek | Contrasted |
| Saunier Duval Thematek C 18 E | Thematek | Contrasted |
| Saunier Duval Thematek C 18 EV | Thematek | Contrasted |
| Saunier Duval Thematek S F 24 E | Thematek | Contrasted |
| Saunier Duval Thematek S C 24 E | Thematek | Contrasted |
| Saunier Duval Thema F 24 E | Thema | Contrasted |
| Saunier Duval Thema C 24 E | Thema | Contrasted |
| Saunier Duval Thema C 24 EV | Thema | 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. 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.
- 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.
- 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 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 at the tap while the heating is working fine, or vice versa.
Cause: The valve does not change position and does not direct the water to the correct circuit.
Force the demand for hot water with the heating turned off to rule out priority issues.
- 02
The boiler does not switch modes when it should: it gets stuck.
Cause: The internal mechanism gets stuck, usually due to the accumulation of limescale in the gas valve.
With the cold installation, look for accessible screws or stems to manually move the valve and check if it is stuck.
- 03
A puddle of water or constant dripping appears near the gas valve.
Cause: The seals lose elasticity with heat and allow water to pass through.
Dry the area, run a complete cycle, and locate the source of the drip before replacing the part.
- 04
The water takes a long time to heat up or does not reach the temperature indicated by the thermostat.
Cause: Part of the water is diverted to the heating circuit instead of going to the domestic hot water.
Compare the heating time with the radiators off and on: if it improves significantly with the radiators off, the valve is not closing properly.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F14 | Heating temperature > 95 °C (temperature limiter). | If the 3-way valve (S1020800) gets stuck or does not switch, the boiler remains in the heating circuit during DHW demand, causing overheating and F14; verify by forcing DHW/heating demand and checking that the actuator moves the spindle and that the 3-way valve is not seized/calcified. |
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
- 0 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Frequently asked questions about the 3-way valve S1020800
Is this Saunier Duval ThemaClassic C24E 3-way valve Ref. S1020800 compatible with my ThemaClassic C24E boiler?
What other models are compatible with this 3-way valve?
What happens when the 3-way valve fails in a Thematek boiler?
What is the reference for the 3-way valve that I need for my boiler?
What fault code is related to this 3-way valve?
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