1
Direct Vent
Twin Pipe Overview
Combustion air and exhaust vent directly through separate
penetrations.
Twin Pipe Termination Clearances
12 in. (0.30 m)
minimum
Exhaust
12 in. (0.30 m)
minimum
above
combustion
air opening
Roof
Twin Pipe Vertical Termination
of Multiple Water Heaters
For illustration purposes only. Listed equivalent length is based on worst case scenario of
3 X 90° elbows or 18 equivalent ft.
30
(Twin Pipe)
12 in. (0.30 m) minimum
12 in. (0.30 m) above
grade or anticipated
snow level
Combustion
air
Combustion
Air
Combustion air termination not permitted in shaded area
Horizontal Vent and Combustion Air Piping
Rinnai Tankless Water Heater Installation and Operation Manual
Exhaust
Wall
Exhaust
Zone
Exhaust
12 in. (0.30 m)
Combustion
minimum
12 in. (0.30 m) above
grade or anticipated
snow level
Air