Demand Duo
™
H
-
Series Installation and Operation Manual
17
•
When installed as direct vent, refer to the
Tankless Water Heater Installation and
Operation Manual for a complete list of
approved vent manufacturers and products.
You must use vent components that are
certified and listed with the water heater
model.
•
Avoid dips or sags in horizontal vent runs by
installing supports per the vent
manufacturer
’
s instructions.
•
Support horizontal vent runs every four feet
and all vertical vent runs every six feet or in
accordance with local codes.
•
Venting should be as direct as possible with
a minimum number of pipe fittings.
•
Engineered vent systems must be firmly
pressed together so that the gaskets form an
air tight seal.
•
The vent piece connected to the water heater
must be secured with one self
-
tapping screw.
•
When installed as Non
-
Direct Vent (Room
Air), the venting must be Category IV and of
a type listed by a national recognized testing
agency or PVC (when allowed by local code).
WARNING
DO NOT use cellular core PVC/CPVC.
DO NOT use Radel or galvanized materi-
al to vent this appliance.
DO NOT cover non
-
metallic vent pipe
and fittings with thermal insulation.
DO NOT combine vent components from
different manufacturers.
DO NOT reduce the vent diameter.
DO NOT connect the venting system with
an
existing vent or chimney.
DO NOT common vent with the vent pipe
of any other manufacturer
’
s water heater
or appliance.
IMPORTANT
For venting information not specified in this
section, refer to the Installation and Operation
Manual for Condensing Tankless Water
Heaters (supplied with each tankless water
heater). This manual includes complete
venting information, including approved vent
manufacturers and terminations.
Topics in this section
•
Venting Requirements
•
Select a Vent Type
IMPORTANT
If it becomes necessary to access an
enclosed vent system for service or
repairs, Rinnai is not responsible for any
costs or difficulties in accessing the vent
system. The warranty does not cover
obtaining access to a vent system in an
enclosed environment.
•
If the vent system is to be enclosed, it is
suggested that the design of the enclosure
shall permit inspection of the vent system.
The design of such enclosure shall be
deemed acceptable by the installer or the
local inspector.
•
Refer to the instructions of the vent system
manufacturer for component assembly in-
structions.
