O-Ring - for Wrekin SSi UV Quartz Sleeve 30x4mm EPDM - Master

This 30x4mm EPDM O-ring is the replacement seal for Wrekin SSi UV quartz sleeves, fitting the 15WQS, 30WQS and 75WQS models. WrekinWater stocks it as the correct-size fix for a sleeve joint that has started to weep, rather than asking you to guess at a generic rubber seal from a hardware shop. EPDM is a durable rubber compound well suited to the chlorinated, warm conditions inside a UV chamber.

Signs this seal needs replacing

• Water is weeping or dripping from the quartz sleeve joint.
• The old O-ring feels hard, flattened, or cracked when you remove the sleeve.
• The joint keeps leaking even after you've refitted and retightened the housing.
• The rubber has taken on a permanent groove from sitting compressed for a long time.

This EPDM O-ring keeps the joint between the quartz sleeve and its housing watertight on Wrekin SSi 15WQS, 30WQS and 75WQS systems. EPDM is chosen because it copes reasonably well with the chlorine and warmth found inside a working UV chamber, but no rubber lasts forever under those conditions — over time it hardens and loses its ability to compress and seal. Left in place, a perished O-ring will eventually let water weep past the sleeve.

WrekinWater has been fitting and supplying parts for SSi UV systems as part of a wider stock of major water treatment brands for over 15 years, so we hold the correct EPDM size rather than a generic substitute. Getting the exact 30x4mm dimension matters here — too loose a fit and the joint will never seal properly, however hard you tighten it.

How to replace it

1. Isolate the water supply to the UV unit and depressurise the line.
2. Undo the sleeve retaining nut or union and withdraw the quartz sleeve from the housing.
3. Remove the old O-ring and wipe away any scale from the sleeve and the housing seat.
4. Lightly grease the new 30x4mm EPDM O-ring with food-safe silicone grease before fitting.
5. Refit the sleeve and union, restore the water supply, and check the joint for leaks.