Rinnai RCi Series Tankless Water Heaters utilize concentric venting with an inner pipe that is designed to withstand varying flue temperature conditions that may be experienced over the life of a condensing product. 

The Ubbink Rolux® condensing concentric vent system is considered part of the direct vent tankless water heater, and has been tested and approved with the appliance by a third party testing agency. 

Standard Features

• Engineered especially for gas appliance venting
• Positive fit and lock allows for installation assurance
• Two layers of pipe equals two layers of protection
• Seals at every joint expand and contract with weather and temperature changes, so there's no flexing or cracking in the venting
• No flammable, messy or harmful glues, cements, or solvents are used
• Zero clearance to combustibles
• Single penetration through wall for both intake and exhaust