1
Direct Vent
Twin Pipe Example Vent Applications
Slope horizontal exhaust 1/4 in. per foot towards the water heater. DO NOT slope combustion air pipe towards
the water heater.
This configuration requires the use of
a Concentric Vent Termination
2 in. or 3 in.
PVC/CPVC
IPEX / Royal
Concentric
Side Wall
Termination
Configuration
2 in. or 3 in.
Schedule 40
PVC/CPVC
Snorkel
Termination
Configuration
2 in. or 3 in.
Schedule 40
PVC/CPVC
Elbow or Tee
Side Wall
Termination
Configuration
2 in. or 3 in.
PVC Low
Profile
Termination
Configuration
Twin Pipe Maximum Vent Length
Twin Pipe Maximum Equivalent Length Table
Vent Sizes
2 in. (51 mm)
Vent Lengths
65 ft (20 m)
•
45° elbow is equivalent to 3 ft (1 m)
•
90° elbow is equivalent to 6 ft (2 m)
32
(Twin Pipe)
3 in. (76 mm)
150 ft (46 m)
This configuration requires the use of
a Concentric Vent Termination
2 in. or 3 in.
PVC/CPVC
IPEX /Royal
Concentric
Vertical
Termination
Configuration
2 in. or 3 in.
Schedule 40
PVC/CPVC
Standard
upside down
"U" Vertical
Termination
Configuration
2 in. or 3 in.
Schedule 40
PVC/CPVC Tee
Vertical
Termination
Configuration
WARNING
Exhaust and
combustion air
MUST NOT be
brought
together into
a single PVC
pipe using a
pipe fitting.
Rinnai Tankless Water Heater Installation and Operation Manual
Single
Pipe
Combustion
Air
Exhaust