Reznor SC Duct Furnace Unit Installation Manual - Manual (Page 21)

Form I-SC, P/N 207696 R11, Page 21
6.4.2 Duct Furnace
Blower Connection
Proper air arrangement of blower and duct furnace with respect to angle of approach
of the duct connection and the arrangement of the discharge opening of the blower are
shown in FIGURE 19. Blowers should be bottom horizontal discharge when coupled
to the duct furnace. When a top horizontal discharge blower is connected to the duct
furnace, be sure that sufficient length of duct is provided to permit an even flow of air
at the furnace. Or, insert baffles between the blower and the heater to assure an even
flow of air across the heat exchanger.
Direct
Coupling
Slanted Transition
Suggested blower connections for straight through airflow. Use
either method for good air coverage and efficient operation.
15°
6” (152mm)
Remote
24”
(610mm)
minimum
Turning Vanes
3”
(76mm)
3”(76mm)
3”(76mm)
6” (152mm)
6” (152mm)
X
15°
Y
No air
X
No air
Z
NOTE: “X” should
never be less than 1/2 “Y”
NOTE: “X” should
never be less
than 1/2 “Y”
NOTE: Angle “Z”
should never be
more than 15°
Turning Vanes 3”
(76mm)
3”(76mm)
3”(76mm)
6” (152mm)
6” (152mm)
Z
NOTE: Angle “Z”
should never be
more than 15°
X
15°
No air
No air
GOOD
GOOD
POOR POOR
POOR
POOR
Y
Y
NOTE: “X” should
never be less than
1/2 “Y”
FIGURE 19A -
Straight
Through Air
vanes should be used in elbows or turns in the air inlet
to ensure proper air distribution (See Paragraph 6.4.2).
If it is determined that the blower CFM is greater than
allowed or desirable, see Paragraph 6.4.3 for instruc-
tions on determining the correct size of bypass duct
required.
Or, if a higher CFM is required through the furnace
within the limits in the chart on the right, install the high
CFM conversion kit, P/N 263309, that was shipped with
the unit.
Model
SC Size
High Air Throughput (CFM) with Kit, P/N 263309
MAXIMUM MINIMUM
100 3700 980
125 4630 1230
150 5555 1480
175 6480 1725
200 7405 1975
225 8330 2220
250 9255 2465
300 11110 2960
350 12900 3455
400 14815 3950
FIGURE 19B -
With Elbows
Up or Down
WARNING
The furnace must be installed on the positive pressure side of the air-circulating blower.
CAUTION: Abrupt angle approaches such as shown in FIGURES 19B and 19C can be
detrimental to unit life. Be certain that ample air is directed at the base of the tube section
by using turning vanes as shown. See Hazard Levels, page 2.
Direct
Coupling
Slanted Transition
Suggested blower connections for straight through airflow. Use
either method for good air coverage and efficient operation.
15°
6” (152mm)
Remote
24”
(610mm)
minimum
Turning Vanes
3”
(76mm)
3”(76mm)
3”(76mm)
6” (152mm)
6” (152mm)
X
15°
Y
No air
X
No air
Z
NOTE: “X” should
never be less than 1/2 “Y”
NOTE: “X” should
never be less
than 1/2 “Y”
NOTE: Angle “Z”
should never be
more than 15°
Turning Vanes 3”
(76mm)
3”(76mm)
3”(76mm)
6” (152mm)
6” (152mm)
Z
NOTE: Angle “Z”
should never be
more than 15°
X
15°
No air
No air
GOOD
GOOD
POOR POOR
POOR
POOR
Y
Y
NOTE: “X” should
never be less than
1/2 “Y”
FIGURE 19C -
With Elbows
Left or Right