Installation Guide

Rinnai Tankless Water Heater Installaon and Operaon Manual 39
Common Vent (Indoor Units Only. Direct Vent and Non-Direct/Room Air Vent)
3
Sample Inline, Freestanding Conguraon
Common Vent Maximum Equivalent Vent Lengths
For the table below:
• Header is the main vent pipe into which several vents connect.
• Vent Length is the distance from the end of the header to the
vent terminaon.
• Maximum vent length starts at the end of the header system.
Header
Vent Length
Common Vent Maximum Vent Length
Water Heater
Model
# Water
Heaters
Vent Diameter
Max System
BTU/HR
3 in. 4 in. 6 in.
RU199i (REU-N3237FF-US)
RU180i (REU-N2934FF-US)
2
398,000
360,000
65 
(20 m)
150 
(46 m)
150 
(46 m)
RU160i (REU-N2530FF-US)
RU130i (REU-N2024FF-US)
2
320,000
260,000
90  150  150 
Common venng allows mulple Rinnai Tankless Water Heaters to
share the same vent system.
When operang mulple water heaters in a common venng
system, it is recommended to use Rinnai’s EZ Connect cable
(purchased separately) which electronically connects two water
heaters so they funcon as one hot water source.
Do not common vent this water heater with any other water
heater or appliance.
Common vent equivalent lengths include polypropylene pipe (PP) or PVC in a back-to-back or inline conguraon.