Viessmann Cascade Communication Module Kmk Bus For Vitodens 200 W Series Boilers. Compatible with Vitodens 200-W Series Residential Wall-Mounted Gas Condensing Boilers Any adjustments installations service or maintenance must be completed by a licensed professional heating contractor who is qualified to work with hot water boilers Check with manufacturer before ordering replacement parts to ensure a proper fit Give the manufacturer the 16-digit boiler serial number or the 12-digit ASME/NB serial number Package Contents: Viessmann 7441586 Cascade Communication Module Kmk Bus For Vitodens 200 W Series Boilers Viessmann 7441586: Cascade Communication Module Kmk Bus For Vitodens 200 W Series Boilers