028103 SITA UV 405AL, 405 LCD/LCD Plus Replacement Quartz Sleeve QJ23500DE (Domed End)

This domed-end quartz sleeve, part code QJ23500DE (SITA reference 028103), is the correct replacement for SITA UV 405AL, 405 LCD and 405 LCD Plus disinfection systems, supplied by WrekinWater. It fits over the UV lamp inside these units, keeping the lamp dry and protected while still allowing UV-C light through to treat the water. Replace it once the existing sleeve shows cloudiness, scale, or has reached its usual service interval.

Signs your quartz sleeve needs replacing

• The sleeve has turned cloudy or hazy instead of remaining clear glass.
• You notice scale, staining, or scratching on the outside of the sleeve.
• Your 405 LCD or LCD Plus display is showing a low UV intensity warning.
• The sleeve is around 12 months old or older and has not yet been changed.

Inside the SITA UV 405AL and LCD models, the quartz sleeve is what allows the lamp to sit safely dry inside the flow of water while still projecting UV-C light through the glass to disinfect it. Scale from hard water and general mineral fouling settle on the outer surface over time, and the quartz itself can dull with age, both of which reduce how much UV light actually reaches the water. This can happen gradually enough that the lamp continues to light and the system appears to run normally while disinfection quietly weakens.

WrekinWater, based in Bettisfield, Shropshire, has supplied SITA and other major UV brand parts to more than 50,000 customers over 15 years. Ordering the QJ23500DE ensures a sleeve matched exactly to your 405AL or LCD Plus system, from a family-run supplier rated Excellent on Trustpilot.

How to replace it

1. Isolate the water supply to the SITA unit and switch off the power.
2. Undo the retaining nut or union at the end of the housing and withdraw the UV lamp first.
3. Slide out the old QJ23500DE sleeve and clean any scale from inside the housing.
4. Fit new O-rings to the sleeve before inserting the replacement domed sleeve.
5. Refit the lamp and reassemble the retaining nut or union.
6. Restore water and power, check for leaks, and run to drain briefly before using the water.