3-Way Valve Motor Saunier Duval Isofast F35 E H-MOD (Saia-Burgess) Ref. S1053700
Three-way valve actuator motor for Saunier Duval boilers from the Isofast, Isomax, Isosplit, Isotwin, Semia, and Thema series. The actuator is a Saia-Burgess with code UCL53N04A1DZ1 and a duty cycle of 20% ED, according to the label. It is replaced when the valve does not switch between heating and domestic hot water or the motor does not reach the end of its travel.
Saunier Duval boilers compatible with reference S1053700
3-way valve with reference S1053700. 23 verified compatibilities: Themafast and Themafast C 25E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Themafast | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast C 25E | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast C 30E | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast F25E | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast F30 | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast Condens F25 | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Themafast Condens F 30 | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Condens F 24E | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Condens F 30E | Themafast / Themafast Condens | Contrasted |
| Saunier Duval Isofast | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isofast F 30E | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isofast F 35E | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isofast 21 F25 | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isofast 21 F30 | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isofast 21 F35 | Isofast / Isofast Condens | Contrasted |
| Saunier Duval Isotwin C 30 | Isotwin / Isotwin Condens | Contrasted |
| Saunier Duval Isotwin F 25 | Isotwin / Isotwin Condens | Contrasted |
| Saunier Duval Isotwin F 30 | Isotwin / Isotwin Condens | Contrasted |
| Saunier Duval Isotwin F 30A | Isotwin / Isotwin Condens | Contrasted |
| Saunier Duval Isomax C 30 | Isomax / Isomax Condens | Contrasted |
| Saunier Duval Isomax F 35 B | Isomax / Isomax Condens | Contrasted |
| Saunier Duval Isomax F 35 E | Isomax / Isomax Condens | Contrasted |
| Saunier Duval Isomax F 35 H | Isomax / Isomax Condens | 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. S1053700 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 S1053700. 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 S1053700 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 valve motor stops moving or feels hot to the touch.
Cause: This motor is designed to operate intermittently; if the boiler switches modes too frequently, it may overheat and lock up.
Leave the boiler off for a few minutes and try again; if it starts moving again after cooling down, the motor is at its limit and it is advisable to replace it.
- 02
The boiler shows a fault with the 3-way valve or the end-of-travel motor.
Cause: The motor does not indicate to the control board that it has reached the final position.
Check that the coupling between the motor and the gas valve shaft is properly adjusted; sometimes it can become misaligned just with use.
- 03
The motor makes noise, gets stuck, or does not rotate completely when changing position.
Cause: The motor gear is worn or broken and does not complete the cycle.
Observe if the motor turns a little and then goes back; that pattern is typical of a broken gear tooth.
- 04
The valve does not switch between heating and domestic hot water.
Cause: The motor does not move the internal stem of the valve even though it receives the command from the control board.
With the motor disassembled, check by hand if the valve shaft rotates freely; if it is stuck, the problem is the valve and not the motor.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.318 | The 3-way motorised valve does not move. | The motor of the 3-way valve (S1053700) is blocked/faulty or its connector/harness is loose; verify by actuating the valve with the actuator test (e.g., T.002) and checking in d.35 that the position does not change, as well as reviewing the connection and continuity to the motor. |
| F.326 | The hydraulic test of sensors/actuators has detected that at least two hydraulic components are not functioning. | A documented cause is the blocked/defective 3-way motorised valve (S1053700); check its operation with T.002 or P.008 and observe in d.35 if it does not change position, in addition to checking the connector and wiring harness. |
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 S1053700.
- Catalogue reference
- S1053700
- 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
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- Actuator manufacturer
- Saia-Burgess
- Actuator code
- UCL53N04A1DZ1
- Duty cycle
- 20% ED
Frequently asked questions about the 3-way valve S1053700
Who manufactures the valve motor for the Isofast F35 E H-MOD Ref. S1053700?
When should the motor of the 3-way valve be replaced in an Isofast F35 E H-MOD?
Is this motor Ref. S1053700 compatible with the Isomax F35 E or the Isotwin C30?
What is the duty cycle of the Saia-Burgess UCL53N04A1DZ1 actuator?
What fault codes are documented for this valve motor?
What reference should I look for regarding the 3-way valve motor of the Isofast F35 E H-MOD?
Spare parts related to Saunier Duval Themafast / Themafast Condens
