Navien NCB-190/060H, Installation & Operation Manual

Page: 82 / 145

82 Installing a Common Vent System
9.1.1 Guidelines for a Common Vent
System
CAUTION
●
To ensure the correct operation of the
common vent system,
-
a cascade communication cable MUST be
installed between all units in the common
vent system by the installer.
-
backflow vent dampers must be installed
in the exhaust duct of each boiler unit.
-
use direct vent (with separate intake
and exhaust vent) or indirect vent
(combustion air drawn from room)
systems.
●
Common vent installations for use with
natural gas and propane are only approved
for up to 4,500 ft.
●
This section covers the installation of a
common vent system for
NCB-H boilers
only
.
To ensure the safe and correct installation of
the common vent system, carefully follow the
instructions and guidelines.
●
Check to see if all contents are included in the
package (refer to the “Included Items” on page
87).
●
An NCB-H boiler unit and up to 7 NPE water
heater units may be connected to one common
vent system. In a cascade system that has more
than 7 NPE water heaters, use 2 common vent
systems, or consult Navien.
●
Use only approved PVC cements when
connecting pipes, joints, or elbows.
●
Position the boiler units as close as possible to the
vent termination.
●
Install a new vent system with this appliance. If an
existing vent system is reused, thoroughly inspect
it for punctures, cracks, or blockages prior to
connecting it to the boiler unit.
●
Horizontal vent pipe runs must be supported
every 4 feet (1.2 m) (minimum). All vertical vent
pipe runs must be supported every 6 feet (1.8 m)
(minimum). Support the vent pipe with hangers
at regular intervals or as required by local codes.
●
Install a backflow damper for each boiler unit. Use
only the damper specified in this manual.
9.1 About the Common Vent
System
The Navien Common Vent System* provides an easy
way to install the vent system for an NCB-H boiler
unit and up to 7 NPE water heater units. By sharing
the main intake and exhaust vent pipes, effective
system venting is available with less venting
materials and minimal number of penetrations on
the walls or roofing.
* Independently tested and approved by CSA
Read all safety messages and carefully follow the
guidelines in this manual when installing a common
vent system for the NCB-H boiler units.
WARNING
Improper venting of the boiler units can result
in excessive levels of carbon monoxide, which
can lead to severe personal injury or death.
The
boiler units must be vented in accordance
with the “Venting of Equipment“ section of
the latest edition of the ANSI Z223.1/NFPA
54 Natural Fuel Gas Code in the USA, as
well as all applicable local building codes
and regulations. Follow all instructions and
guidelines when venting the boiler units.
Venting should be performed only by a licensed
professional.
9. Installing a Common Vent System