14
INDOOR INSTALLATION AND VENTING:
POSITIVE AND NEGATIVE PRESSURE VENTING SYSTEMS
The heater is designed such that it may be vented using either a negative-pressure or a positive-pressure
venting system. The appropriate system of venting for a particular site will depend on many factors such as
vent termination needs (horizontal/vertical), and the cost of venting system. Table 3 lists the indoor venting
kits available and the limitations of each system. Multipe forced- or induced-draft units should never be vented
uisng common venting or vent terminations.
Table 3
Indoor Vent Kits and Limitations of Venting Systems
Indoor Vent Kit Part
Number
Description
For Use With
Heater
Models
Vent Pipe Limitations
Vent Pipe
Material
Vent
Termination
Requirement
UHXNEGVT12501
Indoor Vent Adapter Kit,
Negative Pressure,
Vertical Venting
Applications
TR250
50 ft max vertical height,
25 ft max horizontal length
(horizontal length cannot
exceed 1/2 of vertical height),
3 elbows max
Single or Double
Wall Galvanized
Non-Sealed
Vent Pipe
Vertical Only,
Termination Above
Roof of House/
Building
UHXNEGVT14001
TR400
UHXPOSHZ12502
Indoor Vent Adapter Kit,
Positive Pressure,
Horizontal or Vertical
Venting Applications
TR250
50 ft max with 1 elbow,
40 ft max with 2 elbows,
or 30 ft max with 3 elbows
(horizontal or vertical)
Single or Double
Wall Stainless
Steel Sealed
Vent Pipe
Horizontal or
Vertical, Termina-
tion Immediately
Outside Wall of
House/Building
UHXPOSHZ14002
TR400
CLEARANCES:
The heater must be installed such that the installation and service clearances from combustible materials
shown in Table 4 are maintained. This heater may be installed
on combustible fl oors. Do not install heater in a closet.
AIR SUPPLY:
Indoor installations and outdoor shelters (confi ned spaces)
must be provided with adequate combustion and ventilation air
vents to assure proper heater operation. These vents must be
sized according to the requirements stated in paragraph A or B
below (whichever applies to the installation). These vents must
never be obstructed when heater is in operation.
When air blowers are used in spa/hot tub installations and are
located in proximity to the heater, caution must be observed to ensure suffi cient combustion air is available to
the heater for proper combustion. A separate blower air duct is recommended.
Table 4
Indoor Installation Clearances
Heater Panel
Required Clearance
Top
36 inches
Front
24 inches
Back
6 inches
Water Connection Side
12 inches
Side Opposite Water
Connection
6 inches