Navien NPE Installation & Operation Manual page 35

3.6.1 Selecting a Vent Type
Navien NPE Series water heaters are Category IV appliances and are prepared at the factory to be direct vent (sealed combustion) appliances
that draw all of their required combustion air directly from the outdoors. Navien recommends direct air vent installations whenever possible to
avoid back drafting cold air through the water heater. If you cannot use a direct vent, ensure that an ample supply of make-up air is available
in the installation location.
Navien also recommends installing a new vent system with this appliance. If reusing an existing vent system, thoroughly inspect it for
punctures, cracks, or blockages prior to connecting it to the water heater.
Direct Venting
The water heater uses 2 in or 3 in diameter exhaust and 2 in or 3 in diameter intake air ducts. To ensure the draw of air directly from and
exhaust of air directly to the outside of the building, create an airtight seal from the water heater collar to the vent termination.
Intake materials can be made of ABS, PVC, CPVC, PP, galvanized steel, corrugated aluminum or any other such materials. If you use a
corrugated material, ensure that there is not inadvertent crimping of, or damage to, the intake air pipe.
When using direct venting, maintain the following venting clearances, as required by ANSI Z21.10.3 and the National Fuel Gas Code, ANSI
Z223.1/NFPA 54, and CAN/CGA B149.1 Natural Gas and Propane Installation Code:
Ref Description
A Clearance above grade, veranda, porch, deck, or balcony
B Clearance to window or door that may be opened
C Clearance to permanently closed window
Vertical clearance to ventilated soffit located above the
D terminal within a horizontal distance of 2 ft (61 cm) from
the center line of the terminal
E Clearance to unventilated soffit
Canadian Direct Vent Installations
12 in (30 cm)
36 in (91 cm)
*
*
*
1
US Direct Vent Installations
12 in (30 cm)
12 in (30 cm)
*
*
*
Installing the Water Heater
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