3-Way Valve Saunier Duval 3 Thema NOx F25 B 1 Ref. S10255
RefurbishedSaunier Duval3-way valves

3-Way Valve Saunier Duval 3 Thema NOx F25 B 1 Ref. S10255

60 €VAT includedIn stock · 1 unit

3-way valve: refurbished spare part that diverts water between heating and domestic hot water. Useful if it provides hot water but does not heat radiators, or vice versa. Compatible with Isofast Condens F 35 E, Isofast Condens F 30 E, Isofast Condens F 35-A (ref. S10255). Includes a one-year warranty and delivery within 2–4 working days in the EU.

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Delivery in 2–4 working days
1-year warranty
14-day return
Technical support

Key Data

Reference
S10255
Brand
Saunier Duval
Type of part
3-way valves
Available units
1 unit in stock
Status
Refurbished
Warranty
1 year
Shipping
2–4 working days (EU)
Return
14 days

The same part (ref. S10255) equips these models. Verified compatibility; check the reference before purchasing.

Isofast

  • Isofast Condens F 35 E
  • Isofast Condens F 30 E
  • Isofast Condens F 35-A
  • Isofast 21 Condens F 25
  • Isofast 21 Condens F 35-B
  • Isofast 21 Condens F 30-B
  • Isofast F 30 E H-MOD
  • Isofast F 35 E H-MOD

Isomax

  • Isomax C 30
  • Isomax Condens F 35 E
  • Isomax Condens F 35-B
  • Isomax F 35 H-MOD

Isotwin

  • Isotwin C 30
  • Isotwin Condens F 30-A
  • Isotwin F 30 H-MOD

Themafast

  • Themafast C 25 E
  • Themafast C 30 E
  • Themafast F 25 E
  • Themafast F 30 E (2004)
  • Themafast F 25 E H-MOD
  • Themafast F 30 E H-MOD
  • Themafast NOx F 25-A LPG/GN
  • Themafast NOx F 30-NL/LL

Themafast Condens

  • Themafast Condens F 24 E
  • Themafast Condens F 25
  • Themafast Condens F 30 E
  • Themafast Condens F 30 (2010)
  • Themafast Condens F 30 H-MOD

Fault codes related to this part (not the entire boiler). They usually have more possible causes: first rule out electrodes, wiring/connections, and gas supply. Verified with ≥3 sources.

CodeWhat does it mean?Cause and diagnosis (this part)
F.318The 3-way motorised valve is not moving.The 3V motor/actuator is blocked or without power, so it does not switch between heating and DHW. Check by powering and operating the 3V with the tests (e.g., P.008/T.002) and checking its position in diagnosis (e.g., D.035/D.070), motor continuity, and ensure it is not mechanically stuck.
F.326The hydraulic test detects that at least two hydraulic components are not functioning.A blocked 3V or a loose connector causes the hydraulic self-check to fail. Confirm by ordering the movement of the 3V (tests P.008/T.002), checking its position in diagnosis (D.035/D.070), and verifying wiring, motor continuity, and free movement of the shaft.
How do I know if this 3-way valve is for my boiler?
Verify the reference S10255 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part.
What is it used for?
The 3-way valve diverts the water between the heating circuit and the domestic hot water (DHW) circuit.
Does it provide hot water but not heat the radiators (or vice versa)?
Typical symptom that the valve or its motor is not switching; check the actuator motor and ensure the body is not seized.
Which models is it suitable for?
Part shared by various models (see Compatibility). If your model does not appear, send us a photo of the marking and we will confirm it.
Installation and recommendations
Check if you need the motor, the body, or the complete assembly.
What does refurbished mean and what coverage does it have?
Part removed from a boiler out of service, inspected and tested. Includes 1-year warranty and 14-day return policy. Delivery within 2–4 working days in the EU.

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