QTZ36SE Daro Saphir 4, 7 & 10 Replacement Quartz Sleeve

The QTZ36SE is a domed-end quartz sleeve made for the larger Daro Saphir 4, Saphir 7 and Saphir 10 UV disinfection units, supplied by WrekinWater as part code QJ24887DE. It fits over the UV lamp in these units, keeping it dry and electrically isolated while letting UV-C light pass through into the water. Replace it once the existing sleeve shows cloudiness, scaling, or has reached its usual annual change point.

Signs your quartz sleeve needs replacing

• The sleeve looks cloudy or hazy instead of glass-clear.
• A brown or yellow scale ring has formed along the outside of the glass.
• The UV monitor on your Saphir 4, 7 or 10 unit is alarming despite the lamp lighting.
• It has been roughly 12 months since the sleeve was last changed.

The Saphir 4, 7 and 10 are higher-throughput units, so their quartz sleeve has to keep passing UV-C efficiently across a larger lamp and flow rate. As hard water minerals scale the outside of the sleeve and the quartz itself dulls with age, UV transmittance drops steadily, meaning water spends less time exposed to an effective UV dose even though the lamp continues to run normally. Left unchecked, this can let the system fall below the UV intensity needed for reliable disinfection.

WrekinWater has served more than 50,000 customers over 15 years from its base in Bettisfield, Shropshire, and stocks genuine-fit Daro parts including the QTZ36SE. Buying the correct sleeve for your Saphir 4, 7 or 10 unit avoids compatibility issues with a generic part, from a supplier rated Excellent on Trustpilot.

How to replace it

1. Isolate the water supply to the unit and switch off the power at the mains.
2. Undo the retaining nut at the single end of the housing and carefully withdraw the UV lamp.
3. Remove the old QTZ36SE sleeve and clean any scale build-up from inside the housing.
4. Fit a new O-ring and Teflon washer, then insert the replacement domed sleeve.
5. Refit the UV lamp and reassemble the retaining nut without overtightening.
6. Restore power and water supply, check the joint for leaks, and run to drain briefly before use.