3-Way Valve Boiler Saunier Duval ThemaFast Condens F30 - Ref. S1025500
The Saunier Duval ThemaFast Condens F30 three-way valve, reference S1025500, is a component that manages the flow of water between the heating circuit and the domestic hot water circuit. If it fails, you will notice that you have hot water but no heating, or vice versa, and it may even happen that both circuits mix. This valve is compatible with models F 25 E, F 30 E, C 25 E, C 30 E, among others in the ThemaFast range. It can also be installed in boilers from the Isofast, Isomax, and Isotwin ranges. A technician should confirm through diagnosis whether it needs to be replaced when you experience these heating or hot water issues.
- Type of part
- 3-way valves
- Status
- Refurbished
- Catalogue reference
- S1025500
- Warranty
- 1 year
Saunier Duval boilers compatible with reference S1025500
3-way valve with reference S1025500. 18 verified compatibilities: F 35 E-A and F 30 E-A.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval F 35 E-A | Isofast | Contrasted |
| Saunier Duval F 30 E-A | Isofast | Contrasted |
| Saunier Duval C 35 E-A | Isofast | Contrasted |
| Saunier Duval F 35 E H-MOD | Isofast | Contrasted |
| Saunier Duval F 30 E H-MOD | Isofast | Contrasted |
| Saunier Duval Condens F 30 E | Isofast | Contrasted |
| Saunier Duval Condens F 35 E | Isofast | Contrasted |
| Saunier Duval F 35 E | Isomax | Contrasted |
| Saunier Duval F 35 H-MOD | Isomax | Contrasted |
| Saunier Duval Condens F 35 E | Isomax | Contrasted |
| Saunier Duval F 30 H-MOD | Isotwin | Contrasted |
| Saunier Duval Condens F 30 E | Isotwin | Contrasted |
| Saunier Duval F 25 E | Themafast | Contrasted |
| Saunier Duval F 30 E | Themafast | Contrasted |
| Saunier Duval C 25 E | Themafast | Contrasted |
| Saunier Duval C 30 E | Themafast | Contrasted |
| Saunier Duval Condens F 25 | Themafast | Contrasted |
| Saunier Duval Condens F 30 | Themafast | 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. S1025500 is the part for your boiler
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference S1025500. 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 that require diagnosis in the 3-way valve S1025500
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
You take a shower and the water changes from hot to cold, or vice versa, without you touching anything.
Cause: The actuator does not complete the travel and leaves the shutter halfway, mixing the two circuits.
Listen to see if the gas valve motor completes its full cycle (a few seconds of buzzing) when opening a tap before replacing it.
- 02
The heating does not start, but the hot water from the tap does come out, or just the opposite.
Cause: The valve gets stuck in one position and does not switch to the opposite circuit.
Test several consecutive openings and closings of the faucet: if it sometimes switches, it is an indication of jamming, not an electrical fault.
- 03
A dry thump or rattling is heard in the area of the gas valve when switching from heating to domestic hot water.
Cause: The internal mechanism moves with play or the return spring is worn out.
Locate the source of the noise with the boiler running before disassembling anything: sometimes it is a loose pipe nearby and not the gas valve.
- 04
You see water droplets at the base of the boiler, near where the gas valve is mounted.
Cause: The sealing gaskets of the body give way over the years and pressure cycles.
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 fitting.
Fault codes Saunier Duval that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| F.20 | Safety shutdown: temperature limiter. | If the 3-way valve (priority valve) is blocked or disconnected, the primary flow does not switch correctly and the generator overheats, triggering the F.20; to verify, force the test/diagnosis that moves the valve from the service menu and check the power supply/wiring and ensure the shaft/motor are not seized. |
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 3-way valve S1025500.
- Catalogue reference
- S1025500
- Uniclima internal SKU
- V3VCTCF30
- Brand
- Saunier Duval
- Type of part
- 3-way valves
- Units in stock
- 3 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Part data and available documentation
Contrast the label codes, PCB, and revision with the installed part; they are not necessarily equivalent references.
- Catalogue reference
- S1025500
Frequently asked questions about the 3-way valve S1025500
What is the purpose of the 3-way valve in the Saunier Duval ThemaFast Condens F30 boiler?
When should this valve be replaced in the Saunier Duval ThemaFast Condens F30 boiler?
What is the reference for this valve for the Saunier Duval ThemaFast Condens F30 boiler?
Does this valve also work for other boiler models?
What fault code is documented for this gas valve?
What is the reference for the 3-way valve that I need for my boiler?
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