Both the PVC-2CT and PVC-3CT concentric terminations may be used vertically. The PRC-1 Plastic Rain Cap must be used. Please view the full installation manual on our support site: https://support.noritz.com/technical-literature
The previously offered VK3-H-PVC is approved for vertical termination only with installation of the vertical adapter set accessory, part # VK3-PVC-VAS. Otherwise, vertical installations require that 2 penetrations be made with at least 3′ of horizontal separation.