Navien NPE Installation & Operation Manual page 50

Clearances Between Multiple Units
Ensure that the installed water heaters satisfy all installation
clearances provided in the manual. It is essential that there is
sufficient clearance space for the common vent system to work
properly.
The water heater units can be mounted either IN-LINE or BACK TO
BACK.
Navien Modular Conf iguration with Rack System
In-line Setup
50 Installing a Common Vent System
Back to Back Setup
<Clearance Chart for Common Vent Applications>
Bottom 12" (300 mm)
Back 0.5" (13 mm)
Side 3" (76 mm)
Front 4" (100 mm)
Top 9" (229 mm)
The recommended clearance from the TOP of the unit
Note
is 36" for servicing the common vent.
Additionally, the recommended clearance from the
FRONT of the unit is 24" for maintaining and servicing.
General and Local Standards Information
When installing and operating the common vent system, the
following standards and regulations must be complied with and
adhered to:
Local codes or, in the absence of local codes, the National Fuel
Gas Code, ANSI Z223.1/NFPA 54.
Appliance manufacturer's Installation Instructions.
Regulations on the supervision of construction.
Statutory provisions.
Installation and service work must be carried out by licensed
professionals only.