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The Range£2.54Visit shop Thomas Dudley 127Mm Diaphragm Washer For Siphon - Oval Design - Silver
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The McAlpine 127mm (5 inch) Diaphragm Washer is an essential replacement component for DIYers and professional plumbers maintaining siphon-based toilet flushing systems. Designed to ensure a perfect, airtight seal, this washer restores flushing efficiency and prevents leaks caused by worn-out components. While its oval shape provides broad compatibility, users should verify their existing siphon measurements before purchase to ensure a correct fit for their specific cistern model.
| Model Part Number | Ptosys367470 |
|---|---|
| Brand | Thomas Dudley |
You should measure the diameter of your current diaphragm or check the documentation for your siphon; 127mm (5 inches) is a standard size for many siphon systems, but not all.
Yes, this is considered a standard DIY task that requires basic tools and no specialized plumbing skills.
Use a soft brush and a mild scale remover to gently clean the plastic housing where the washer sits.
There is no fixed interval, but it should be replaced whenever you notice a loss of flushing efficiency or visible water running into the toilet bowl.
It is designed for standard 127mm siphon applications, but compatibility depends on the design of the siphon housing rather than the brand name.
Check that the washer is seated perfectly flat and that there is no debris trapped underneath the seal.
Ensure the diaphragm is properly secured to the siphon rod; if it is loose, it cannot create the necessary vacuum.
Ensure the siphon is fully cleared of lime scale, as buildup can prevent the washer from fitting into the groove correctly.
Before starting installation, ensure the water supply to the cistern is turned off.
