Installation Guide

Polypropylene (PP) Common Venting Installation Instructions 28

Installaon Instrucons

Recommended Spacing of Water Heaters

Spacing of the water heaters is crical for the common

vent system to mounng easily and securely. The

common vent headers are made for 20.5” spacing (center

line to center line) between water heaters. If a dierent

spacing is needed, please contact Rinnai concerning your

applicaon. Rinnai recommends using the Tankless Rack

System (TRS) which is designed for 20.5” spacing. The

engineered system is designed to make installaon simple

and greatly reduces installaon me.

Custom Water Heater Spacing

If common venng with LESS than 20.5” between water heaters:

• The installer assumes all responsibility of following local codes. Inspectors can reject the installaon if the

rang plate cannot be seen for all water heaters.

• The Exhaust Header and 3” Diameter Extension Pieces must be cut appropriately to maintain the required

3° slope.

If common venng with GREATER than 20.5” between water heaters:

• The vent extension and 3” Diameter Extension Pieces must be cut to the appropriate length between to

maintain a 3° slope.

• The length of each addional vent extension must be considered in the maximum allowable vent length.

Exhaust Vent Installaon Procedures:

To maintain a 3° slope, use the following

formula to calculate 3” Diameter Extension

Piece length (L):

(L) = (water heater spacing) X 0.05

Example: if the adjacent water heater is

20.5” away

Length (L) = 20.5” x 0.05 = 1.02”

Example: if the adjacent water heater is 26”

away

Length (L) = 26.0” x 0.05 = 1.30”

20.5”

Vent extension

cut to size

Air Intake

extension

3” Diameter

Extension Piece