Reznor UDBS Unit Installation Manual - Manual (Page 17)

Form I-UDB, P/N 202658 R14, Page 17
Confined Space:
A space whose volume is less than
50 cubic feet per 1000 BTUH of the
installed appliance input rating
FIGURE 11 - Definition
of Confined Space and
Required Openings for
Combustion Air
(3)
(3)
(1)
(1)
(2)
(2)
Confined
Space
1. Air from inside the building -- openings 1 square inch free area per 1000 BTUH.
Never less than 100 square inches of free area for each opening. See (1) in
FIGURE 11.
2. Air from outside through duct -- openings 1 square inch free area per 2000
BTUH. See (2) in FIGURE 11.
3. Air direct from outside -- openings 1 square inch free area per 4000 BTUH. See
(3) in FIGURE 11.
NOTE: For further details on supplying combustion air to a confined space, see the
National Fuel Gas Code ANSI Z223.1a (latest edition).
Depending on how the heater was ordered, it is shipped with either horizontal louvers
or a factory-installed duct flange (Option AX4).
Shipped-separate, field-installed discharge options include a duct flange, vertical lou-
vers in addition to the horizontal louvers, a choice of one or two downturn nozzle
sections available with and without vertical louvers; and a polytube adapter for green-
house or similar applications. Follow the instructions included with the field-installed
option package to attach the parts to the heater.
Dimensions of the field-installed downturn nozzles are shown in Paragraph 3.2.
If equipped with a duct flange or a polytube adapter, field-suppled metal or polytube
ductwork will need to be installed. Duct flange dimensions are shown in FIGURE 12.
Polytube adapter dimensions and polytube requirements are shown in FIGURE 13.
6.3 Unit Discharge
FIGURE 12 - Duct
Flange Dimensions
UDBP and
UDBS
"W" "H"
inches mm inches mm
30, 45 13-13/16 351 10 254
60, 75 13-13/16 351 13 330
100, 125 13-13/16 351 21 533
150, 175, 200 23 584 16 406
225, 250 23 584 22 559
300, 350, 400 23 584 30 762 3/4”
(19mm) typ
3/4” (19mm) typ
H
W
H and W are
the opening
dimensions.
Duct Flange
is 3/4” (19mm).
A
B
B C
Polytube
Adapter
Option CD11
Model UDBP
or UDBS
Heater
Polytube
Ductwork
(field-supplied;
see table,
next page)
FIGURE 13 - Polytube Adapter Dimensions and Requirements for field-supplied Polytube
UDBP & UDBS A B C
75
inches 16-15/16 10-3/8 9
mm 430 264 229
100, 125
inches 17 10-3/8 9
mm 432 264 229
150, 175,
200
inches 16-3/16 13-3/8 12
mm 411 340 305
225, 250
inches 16-3/16 13-3/8 12
mm 411 340 305
300, 350,
400
inches 16-3/16 13-3/8 12
mm 411 340 305