3-Way Valve Saunier Duval Thema C 23 E - Ref. 05740400
The 3-way valve Saunier Duval Thema C 23 E is responsible for directing water between the heating circuit and the domestic hot water circuit. If it fails, you will notice that there is hot water but no heating, or vice versa, and there may even be a mixing of both circuits. The fault codes associated with this part are F.318, F.326, and F.081. This valve is compatible with several models from the Thema range, such as Thema F 23 E, Thema 23, and others from the Themaplus and Combitek ranges. It is advisable to replace it when the mentioned symptoms occur or the fault codes are recorded.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 05740400
Three-way valve with reference 05740400. Seven confirmed compatibilities: Thema F 23 E and Thema C 23 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Thema F 23 E | Thema | Contrasted |
| Saunier Duval Thema C 23 E | Thema | Contrasted |
| Saunier Duval Thema 23 | Thema | Contrasted |
| Saunier Duval Themaplus C 23 E | Themaplus | Contrasted |
| Saunier Duval Themaplus F 23 E | Themaplus | Contrasted |
| Saunier Duval Combitek C 23 | Combitek | Contrasted |
| Saunier Duval Combitek F 23 | Combitek | 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. 05740400 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 05740400. 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 3-way valve 05740400 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
Domestic hot water comes out cold or lukewarm while the heating is working fine.
Cause: The three-way valve does not switch from heating to domestic hot water (DHW).
Check if when requesting domestic hot water you can hear or notice the small motor of the gas valve moving; if there is no movement or noise, it could be the valve or its control.
- 02
The radiators do not heat properly while there is a demand for domestic hot water.
Cause: The valve gets stuck in the DHW position and does not return to the heating circuit when it should.
Check that there is no room thermostat continuously calling for heat before considering the gas valve.
- 03
Water is leaking from underneath the boiler, near the central area of the hydraulic body.
Cause: The gasket or the shaft of the three-way valve loses tightness with use and water leaks.
Dry the area well and check again after a heating cycle and another for domestic hot water, to confirm that the leak is coming from the gas valve and not from another nearby joint.
- 04
A clicking or buzzing sound is heard when switching between heating and domestic hot water.
Cause: It is the normal noise of the actuator of the valve moving the internal mechanism; if the noise is different or lasts longer, the mechanism may be jammed.
Note whether the noise results in a real mode change or remains incomplete, to distinguish between a noisy but functional actuator and one that is faulty.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.318 | The 3-way motorised valve is not moving. | The 3-way valve (actuator or gears) is blocked or without power, so it does not switch between DHW/heating; check by activating the service test and checking voltage/continuity at the motor connector. |
| F.326 | The hydraulic test of the sensor and the actuator has determined that at least two hydraulic components are not functioning. | If the 3-way valve is blocked or disconnected, the hydraulic test detects multiple faults; check the valve movement from the test menu and inspect the connector/wiring harness or replace the assembly if it does not operate. |
| F.081 | The boost has failed. | The brand documents the 3-way valve as a possible cause when it is defective or blocked; confirm by actuating it in service test and, if it does not switch or consumes without turning, replace the valve/motor and check the wiring. |
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 05740400 three-way valve.
- Catalogue reference
- 05740400
- Brand
- Saunier Duval
- Type of part
- 3-way valves
- Units in stock
- 5 units
- 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 Thema F 23 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the 3-way valve 05740400
What is the purpose of the 3-way valve in the Saunier Duval Thema C 23 E?
Is this 3-way valve suitable for the Themaplus C 23 E?
Spare parts related to Saunier Duval Thema
