Is the room fairly small where your 4" exhaust tankless water heater is to be installed? Does the room lack sufficient supply of fresh air? Then you must use a vent kit like this one that brings fresh air into the tankless unit or room.
qty. one 4" diameter termination hood
qty. one 4" diameter 90 degree elbow
qty. one 4" diameter 1' length pipe
qty. one 4" diameter wall thimble
qty. one 4" diameter Universal Appliance Adapter ("UAA")
qty. one 3" diameter galvanized steel fresh air intake hood
qty. one 3" diameter 5' length combustion air duct with clamps (aluminum flex duct pipe)
Note: This kit does not include a condensate drain pipe which may be required depending on your water heater manual guidelines and building code.
• Replace the UAA in this kit with this item if you want to add a backflow preventer and condensate drain.
• Or, this gadget with only the condensate drain can be connected to the UAA in this kit.
• Vent material: AL29-4C stainless steel, except for the fresh air intake hood
• Certification: Tested to meet or exceed Underwriters Laboratories (UL) spec UL1738 and ULS636
• Approval: Cat II, III, IV venting
• Limited Lifetime Warranty
Z-Vent SVE Series IV Installation and Maintenance Instructions, 3" to 24", Single & Double Wall
Z-Vent Dimensional Specifications