3-Way Hydraulic Group with Motor for Isofast Condens - Ref. S1025500
If you notice that you have hot water but no heating, or vice versa, you may need the Hydraulic Group 3-Way with Motor for Isofast Condens. This valve switches the water between the heating circuit and the domestic hot water circuit. If it fails, it can cause the mixing of both circuits or prevent one of them from functioning. It is compatible with several models from the Isofast, Isomax, Isotwin, and Themafast ranges, among others. You should replace it when you experience these symptoms or when the fault code F.20 appears.
VAT included
Consult via WhatsAppSaunier 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
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 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 and faults that the S1025500 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
The radiators heat up, but when the tap is opened, the water takes a long time or does not get hot.
Cause: The motor of the three-way valve does not fully turn towards the DHW side.
Listen to see if the motor makes a sound when you open the tap; if there is no sound at all, the problem may be earlier, in the signal that activates it.
- 02
The motor is making a forcing or buzzing noise, but the boiler does not change mode.
Cause: The internal gear of the motor is worn or jammed and does not move the valve stem.
Pay attention to how long the buzzing lasts and whether it stops on its own or continues persistently, to rule out a simple blockage.
- 03
There is domestic hot water, but the radiators remain cold.
Cause: The valve is stuck in the DHW position and does not allow water to flow to the heating circuit.
Check that the heating demand reaches the control board (thermostat requesting) before assuming that the gas valve is blocked.
- 04
Water is appearing at the base of the boiler, near the body of the group with the red connector.
Cause: The seals of the valve body lose tightness with usage cycles.
Dry the area and check after a while of operation to confirm that the leak is coming from the body and not from a nearby fitting.
- 05
The boiler shows a fault code and stops just when requesting domestic hot water.
Cause: The control unit does not receive confirmation that the gas valve has reached its position and shuts off for safety.
Note the exact code displayed, as it usually indicates whether the warning points to the motor of the three-way valve.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 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
- 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 F 35 E H-MOD Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the 3-way valve S1025500
Is this 3-way hydraulic group with motor H3VF30EA compatible with my boiler?
What problem does changing this hydraulic group in an Isofast Condens F 30 E boiler solve?
Does the H3VF30EA 3-way hydraulic group include the motor?
What fault code is documented for this hydraulic group?
Can I use this hydraulic group in a boiler from the Isomax range?
Spare parts related to Saunier Duval Isofast
