Viessmann Flue Adapter Cpvc 3in For Vitocrossal 300 Cu3A 26/35/45/57 Series Boilers. These Boiler Parts by the experts at Viessmann will work with 26/35/45/57 Series 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. Give the manufacturer the 16-digit boiler serial number or the 12-digit ASME/NB serial number to ensure a proper fit with your boiler. Check with manufacturer before ordering replacement parts to ensure a proper fit-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 to ensure a proper fit. Package Contents: Viessmann 7134770 Flue Adapter Cpvc 3in For Vitocrossal 300 Cu3A 26/35/45/57 Series Boilers Viessmann 7134770: Flue Adapter Cpvc 3in For Vitocrossal 300 Cu3A 26/35/45/57 Series Boilers