Thomas Dudley S7 Cascade 7.5" Dual Flush Syphon — 334643
The Thomas Dudley Cascade+ (334643) is a compact, one-piece syphon engineered to deliver superior flushing performance in most low-level lever-operated cisterns. This 7.5" model features integrated DuoFlush technology, allowing for a full flush by pressing and releasing the lever, or a water-saving partial flush by holding it down. Manufactured in the UK, it is 6/7/9 litre convertible and includes a built-in internal overflow for maximum safety.
Note: As per manufacturer updates, you will be sent the current version as shown in image 2 of the listing.
Identification Guide:
MPN: 334643 | Outlet: 1.5" (38mm) BSP | Height: 7.5" (191mm to spillover) | Certification: WRAS Approved
Choosing the Correct Height
To ensure an optimal flush and prevent cistern lid issues, verify your height before ordering:
- New Installation: Measure the water level line (back of cistern) and add 1" (25mm).
- Existing Cascade: Measure from the bottom of the threaded tail flange to the spillover point (moulded ridge on the domed cap).
Technical Support & Instructions
View the official guide on how to measure your water line.
Cascade S7 Sizing Table
| Height (mm) | Syphon Size | Shop Link |
|---|---|---|
| 178mm | 7" | View FTB12813 |
| 191mm | 7.5" | This Listing |
| 203mm | 8" | View FTB477 |
| 216mm | 8.5" | View FTB478 |
| 229mm | 9" | View FTB479 |
| 241mm | 9.5" | View FTB480 |
Essential Spares: Be Prepared
Common Questions
Q: Does this have an internal overflow?
A: Yes, it can act as an internal overflow provided the spillover point is below any external holes (e.g., the lever hole).
Q: How do I adjust the flush volume?
A: You can adjust the full flush volume by removing the small white plugs on the side of the syphon body.
Q: Fitting to a close-coupled toilet?
A: Trim the threaded tail back to 2-3mm from the back nut to ensure the flush is not throttled.