Viqua Sterilight Quartz Sleeve O-rings BS813

This BS813 O-ring is the replacement seal used at the end of Viqua Sterilight UV quartz sleeves, where open-ended sleeves typically need two per unit. WrekinWater supplies it as a simple, inexpensive fix for a joint that will eventually weep once the original rubber perishes. It's sized to the BS813 standard so it seats correctly against the sleeve and housing without modification.

Signs this seal needs replacing

• Water is weeping or dripping from around the quartz sleeve end cap or union.
• The rubber has gone hard, cracked, or lost its stretch when you remove the sleeve.
• The joint still leaks slightly after you've refitted the housing and retightened it.
• You're already replacing the quartz sleeve and the old O-ring looks flattened or brittle.

This O-ring sits between the quartz sleeve and its housing, and its only job is to keep that joint watertight under mains pressure. Sterilight sleeves see repeated exposure to chlorinated water, warmth from the UV lamp, and the stress of being unscrewed at every service, all of which gradually harden and perish the rubber. Once it loses its seal, water can weep past the sleeve end and, eventually, reach the electrics or lamp connector.

WrekinWater is a family-run business that has supplied UK households and businesses with water treatment parts for more than 15 years, and small consumables like this O-ring are exactly the kind of low-cost fix we're asked for most often. Buying the correct BS813 size means you don't over- or under-compress the seal, which is the easiest way to cause a leak straight after a service.

How to replace it

1. Isolate the water supply to the UV system and relieve any pressure before starting.
2. Undo the retaining nut or union at the base of the housing and carefully withdraw the quartz sleeve.
3. Slide off the old O-ring(s) and clean any scale or debris from the sleeve and housing groove.
4. Lightly coat the new BS813 O-ring with food-safe silicone grease and fit it into place.
5. Refit the quartz sleeve, tighten the union by hand plus a small turn, then restore the water supply and check for leaks.