G436-Li

The G436-Li is a replacement UV lamp compatible with the Wrekin SE1, the GER25SE Daro Saphir 2, and the T521 Wonder UV system. WrekinWater supplies it as the correct annual replacement lamp for these units, since UV output falls well before a lamp actually stops lighting. It's a straightforward swap that keeps disinfection performance where it should be.

Signs you need this part

• It's been around 12 months since the lamp was last changed, the standard UV maintenance interval.
• The lamp still lights but you have no way of confirming its UV output has stayed at safe levels.
• Your system's UV monitor or alarm, where fitted, has flagged low output.
• You've noticed a change in water taste, smell, or clarity despite the lamp appearing to work.

UV lamps lose intensity gradually over their working life, well before they visibly dim or fail to strike, which is why replacement is scheduled by time rather than by waiting for the lamp to stop working. A lamp that's past its 12-month interval may still light up but can be producing UV output too low to reliably disinfect the water passing through the chamber. Running past this point means you could be trusting a system that looks like it's working while no longer doing its job properly.

WrekinWater has served more than 50,000 customers over 15 years from our base in Bettisfield, Shropshire, and is rated Excellent on Trustpilot. We stock the correct replacement lamps for the systems we sell, including this one, so you're not left guessing which lamp fits your unit.

How to fit it

1. Isolate power to the UV unit and, where relevant, the water supply.
2. Undo the retaining nut or cap and carefully withdraw the old lamp from the quartz sleeve.
3. Wipe the quartz sleeve clean before fitting the new lamp.
4. Insert the new G436-Li lamp fully into the sleeve, taking care not to touch the glass with bare hands.
5. Refit the retaining nut or cap and reconnect the lamp's electrical connector.
6. Restore power and confirm the unit lights up and runs normally.