987158-UIM-B-1013
Johnson Controls Unitary Products
9
SECTION III: FILTERS
FILTER INSTALLATION
All applications require the use of a field installed filter. All filters and
mounting provision must be field supplied.
Filters must be installed external to the furnace cabinet.
DO NOT
attempt to install filters inside the furnace.
1. Air velocity through throwaway type filters may not exceed 300 feet per
minute (91.4 m/min). All velocities over this require the use of high velocity
filters.
2. Do not exceed 1800 CFM using a single side return and a 16x25 filter. For
CFM greater than 1800, you may use two side returns or one side and the
bottom or one side return with a transition to allow use of a 20x25 filter.
SIDE RETURN
Locate the “L” shaped corner locators. These indicate the size of the cut-
out to be made in the furnace side panel. Refer to Figure 14.
Install the side filter rack following the instructions provided with that
accessory. If a filter(s) is provided at another location in the return air
system, the ductwork may be directly attached to the furnace side
panel.
HORIZONTAL APPLICATION
Horizontal Filters
Any branch duct (rectangular or round duct) attached to the plenum
must attach to the vertical plenum before the filter. The use of straps
and / or supports is required to support the weight of the external filter
box.
FIGURE 13:
Dimensions
LEFT SIDE
RIGHT SIDE
.5”
.5”
RETURN END
B
24.25”
29.5”
(For Cladded door add appoximately an additional .75”)
28.5”
Electrical
Entry
Gas Pipe
Entry
Thermostat
Wiring
FRONT
14”
1”
1.5”
23”
SUPPLY END
C
24.38”
20”
.5”
B
Gas Pipe
Entry
Thermostat
Wiring
33”
A
.5”
Electrical
Entry
Vent Connection
Outlet
Vent
Connection
Outlet
4” Diameter
Outlet
Vent Connection
Table 3:
Cabinet and Duct Dimensions
BTUH (kW)
Input
Nominal
CFM (m
3
/min)
Cabinet
Size
Cabinet Dimensions (Inches)
Approximate
Operating Weights
A
A (cm)
B
B (cm)
C
C (cm)
Lbs
60 (17.6)
1200 (34.0)
A
14 1/2
36.8
13 1/2
34.3
10.3
26.2
94
80 (23.4)
1200 (34.0)
B
17 1/2
44.4
16 1/2
41.9
11.8
29.9
103
80 (23.4)
1600 (45.3)
C
21
53.3
20
50.8
13.6
34.5
114
100 (29.3)
1600 (45.3)
C
21
53.3
20
50.8
13.6
34.5
118
100 (29.3)
2000 (56.6)
C
21
53.3
20
50.8
13.6
34.5
122
120 (35.1)
2000 (56.6)
C
21
53.3
20
50.8
15.8
40.1
129
Table 4:
Recommended Filter Sizes (High Velocity 600 FPM)
CFM
(m³/min)
Cabinet
Size
Side
(in)
Bottom
(in)
1200 (34.0)
A
16 x 25
14 x 25
1200 (34.0)
B
16 x 25
16 x 25
1600 (45.3)
C
16 x 25
20 x 25
2000 (56.6)
C
(2) 16 x 25
20 x 25
FIGURE 14:
Side Return Cutout Markings
Some accessories such as electronic air cleaners and pleated media
may require a larger side opening. Follow the instructions supplied
with that accessory for side opening requirements. Do not cut the
opening larger than the dimensions shown in Figure 13.
All filters and mounting provision must be field supplied. All installa-
tions must have a filter installed.
Front of
Furnace
Corner
Markings
Side of
Furnace
