A UV lamp is a scheduled replacement, not a failure item. Its UV-C output falls steadily through life while the lamp continues to light normally, so a reactor with visibly working lamps can be well below its dosing duty. Replace on elapsed operating hours against the measured intensity trend, not on the lamp going out, and handle the new lamp by its ends only. The matching quartz module for the WLR20 is stocked under item 13161-0212. Wedeco was founded in Herford, Germany in 1976 and is now a Xylem brand.