USK 15/25/36/64SE Saphir Quarts Sleeve O Ring and Teflon Washer Set

This USK seal kit from WrekinWater contains the O-ring and Teflon washer needed to reseal a 24mm single-ended quartz sleeve across the full Daro Saphir range, covering Saphir 1, 2, 3, 4, 7 and 10 units. It is the small but essential seal fitted at the sleeve end whenever a quartz sleeve is removed or replaced. Using a fresh kit each time keeps the joint watertight after the housing has been opened.

Signs your quartz sleeve needs replacing

• You are already fitting a new quartz sleeve and the old O-ring and washer are worn or perished.
• There is weeping or a slow drip at the sleeve retaining nut on your Saphir unit.
• The O-ring looks flattened, cracked, or has taken a permanent set from being compressed.
• You are servicing the UV unit and want to reseal the joint properly rather than reuse old seals.

The O-ring and Teflon washer in this kit are what keep the single-ended quartz sleeve joint watertight where it seats into the UV housing on Saphir 1, 2, 3, 4, 7 and 10 units. Rubber seals harden and lose their compression set over time from constant water contact and periodic warmth near the lamp, so refitting a sleeve onto an old, perished O-ring is a common cause of a fresh leak at the retaining nut. Renewing both parts whenever the housing is opened is the simplest way to guarantee a dry, reliable seal.

WrekinWater, based in Bettisfield, Shropshire, has supported more than 50,000 customers over 15 years and keeps the small consumable parts like this USK seal kit in stock alongside the sleeves themselves. Ordering both together from a supplier rated Excellent on Trustpilot means you are not left waiting on a seal kit after the housing is already open.

How to replace it

1. Isolate the water supply to the UV unit and switch off the power.
2. Undo the retaining nut at the single end of the housing and withdraw the lamp, then the quartz sleeve.
3. Remove the old O-ring and Teflon washer from the sleeve end and wipe the seating area clean.
4. Fit the new Teflon washer followed by the new O-ring from this kit onto the sleeve end.
5. Reinsert the sleeve and lamp, then reassemble and hand-tighten the retaining nut.
6. Restore the water supply and power, and check the joint closely for leaks before leaving it in service.