Installation Guide

Rinnai Tankless Water Heater Installation and Operation Manual 39
Twin Pipe Example Vent Applications
Slope horizontal exhaust 1/4 in. per foot (21 mm per meter) towards the water heater. DO NOT
slope intake air pipe towards the water heater.
This configuration requires the use of a
Concentric Vent Termination
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. PVC/CPVC
IPEX/ Royal Concentric
Vertical Termination
Configuration
2 in. or 3 in. Schedule
40 PVC/CPVC or ABS
Snorkel Termination
Configuration
2 in. or 3 in. Schedule 40
PVC/CPVC or ABS
Standard upside down “U”
Vertical Termination
Configuration
2 in. or 3 in. Schedule
40 PVC/CPVC or ABS
Elbow or Tee Side Wall
Termination Configuration
2 in. or 3 in. Schedule
40 PVC/CPVC or ABS
Tee Vertical Termination
Configuration
2 in. or 3 in.
PVC
Low Profile
Termination
Configuration
Exhaust and
intake air
MUST NOT be
brought
together into a
single PVC
pipe using
a pipe fitting.
Single
pipe
Exhaust
Intake air
Table 17. Twin Pipe Maximum Equivalent Length
Twin Pipe Maximum Vent Length
WARNING
Table 16
1. Direct Vent (Twin Pipe )
Vent Sizes 2 in. (51 mm) 3 in. (76 mm)
Vent Lengths
75 ft (23 m) 150 ft (46 m)
45° Elbow
3 ft (1 m) 2.5 ft (0.7 m)
90° Elbow
6 ft (2 m) 5 ft (1.5 m)