Item Description
Replace your Broken Wirquin Derwent Macdee Metro Round Cistern Syphon
NOTE: Ensure you choose the correct shape and size — see the last photograph and the guidance below.
Product Features
- Metro three-piece syphon with quick-release coupling nut for easy maintenance — no need to remove the cistern.
- Metro Rapid ROUND (example shown: DSY7125, 7.5"). See full size options and how to measure below.
- WRAS Approved with internal overflow.
- Supplied with syphon back nut, flush pipe coupling nut, syphon seal, low-level flush pipe seal and diaphragm.
- For internal overflow: measure from base of cistern to waterline and add 1"; this must be at least 10 mm below any cistern aperture.
- Make sure you’re ordering the correct Metro model — similar-looking versions include the Metro single flush and Metro dual flush ranges.
- Current production is supplied in Grey/Black, replacing earlier white/white & blue or grey versions.
Details
- If you’re unsure what size you require, please contact us — we’re happy to help.
- This syphon comes in various sizes and shapes (round / oblong / square / D-shaped). Choose the correct option for your cistern using the guide below.
- Do not confuse this with the one-piece Wirquin syphons — this is the Metro Rapid three-piece design.
Choosing the Correct Size & Shape (Macdee Metro Rapid – Round)
There are multiple sizes in the Metro Rapid Round range. Choosing the correct height ensures optimal flushing performance and prevents fit issues (e.g., the lid not closing).
Method 1 – New Install / Replacing a Different Syphon
- Measure from the bottom of the cistern to the waterline.
- Add 25 mm (≈1") to this measurement.
- Ensure this final measurement is at least 10 mm below any aperture in the cistern.
- Choose the syphon height that best matches this figure (see table below).
Method 2 – Replacing an Existing Metro Rapid (Round)
- Refer to the last photo for where to measure.
- Measure from the bottom of the bell/bottom of the syphon to just under the domed top.
- The measured value corresponds to the required syphon size (see table below).
Round Bell Shape – Size Reference
| Height (cm) (measured as per last photo) |
Syphon Height to Purchase | C-Link Size |
|---|---|---|
| 19.20 cm | 7.5" | 2.25" |
| 20.32 cm | 8" | 2.25" |
| 21.59 cm | 8.5" | 2.75" |
| 22.86 cm | 9" | 2.25" |
| 24.13 cm | 9.5" | 2.25" |
| 25.40 cm | 10" | 2.25" |
| 26.67 cm | 10.5" | 2.25" |
Select your required size from the dropdown at the top of this page.
Questions & Answers
Q1: How does the internal overflow on a toilet syphon work?
A syphon will internally overflow when the water level within the cistern reaches the spillover point. Water then trickles over this point, flows down the down-leg of the syphon and into the toilet bowl.
Q2: After replacing, why won’t the syphon flush, or only flushes if I “pump” the handle?
- Check the quick-release nut is tightened.
- Check the diaphragm washer is flat to the piston base and not torn/damaged.
- Check the sealing washer isn’t kinked or trapped.
- Sometimes the C-link can be a little tight; you may need a slightly longer one or to adjust it so it effectively acts longer.
Need help figuring out if this product is right for your setup?
Send us your best bathroom selfies (or, you know, just your bathroom setup pics) to [email protected] or WhatsApp 07359 625424 us, and we'll help you flush your confusion away!