The ignitor supplies the high-voltage pulse that strikes the ultraviolet lamp arc at start-up, after which the ballast takes over and holds the running current. A failed ignitor is the usual cause of a lamp that will not strike but tests sound, and it is the part to check before condemning a lamp on a no-start. This is the PZS 1000 K TC ignitor. Wedeco was founded in Herford, Germany in 1976 and is now a Xylem brand.