028103C SITA UV 405CAL Replacement Quartz Sleeve QJ23650DE (Domed End)

This domed-end quartz sleeve, part code QJ23650DE (SITA reference 028103C), is the direct replacement for the SITA UV 405CAL disinfection system, supplied by WrekinWater. It surrounds the UV lamp inside the 405CAL unit, keeping it dry while letting UV-C light pass through to disinfect the water. Fit a new sleeve once the existing one has clouded, scaled, or reached its usual annual change point.

Signs your quartz sleeve needs replacing

• The sleeve has clouded over or turned hazy rather than staying transparent.
• There is visible limescale or a brownish film on the outside of the glass.
• The 405CAL unit's UV alarm or indicator is triggering despite the lamp lighting.
• The sleeve has been fitted for around 12 months, the standard replacement point.

On the SITA UV 405CAL, the quartz sleeve keeps the UV lamp completely isolated from the water while still allowing UV-C light to pass through and disinfect it. Over time, mineral scale and iron in the water settle on the outer surface, and the quartz can also dull or micro-scratch with age, reducing UV transmittance. Because the lamp continues to light and function electrically, this drop in disinfection performance is easy to miss without checking the sleeve itself.

WrekinWater has supplied SITA UV parts to more than 50,000 customers over 15 years from its base in Bettisfield, Shropshire. Ordering the QJ23650DE guarantees the correct sleeve for your 405CAL system specifically, from a family-run supplier rated Excellent on Trustpilot.

How to replace it

1. Isolate the water supply to the 405CAL 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. Remove the old QJ23650DE sleeve and clean any scale from inside the housing.
4. Fit new O-rings before inserting the replacement domed sleeve.
5. Refit the lamp and reassemble the retaining nut or union securely.
6. Restore water and power, check for leaks, and run to drain briefly before using the water.