5532522-UIM-B-0619
Johnson Controls Ducted Systems
7
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 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 7.
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 FILTERS
Any branch duct (rectangular or round duct) attached to the plenum
must attach to the vertical plenum before the filter. Use of straps and/or
supports is required to support the weight of the external filter box.
SECTION IV: GAS PIPING
GAS SAFETY
GAS PIPING INSTALLATION
Properly sized wrought iron, approved flexible or steel pipe must be
used when making gas connections to the unit. If local codes allow the
use of a flexible gas appliance connection, always use a new listed con-
nector. Do not use a connector that has previously serviced another gas
appliance.
Some utility companies or local codes require pipe sizes larger than the
minimum sizes listed in these instructions and in the codes. The furnace
rating plate and the instructions in this section specify the type of gas
approved for this furnace - only use those approved gases. The instal-
lation of a drip leg and ground union is required. Refer to Figure 9.
CAUTION
All filters and mounting provision must be field supplied. All installa-
tions must have a filter installed.
NOTICE
Single side return above 1800 CFM is approved as long as the filter
velocity does not exceed filter manufacturer’s recommendation.
Table 3:
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
1600 (45.3)
C
16 x 25
20 x 25
2000 (56.6)
C
(2) 16 x 25
20 x 25
FIGURE 7:
Side Return Cutout Markings
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6,'(2)
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IMPORTANT:
Some accessories such as electronic air cleaners and
pleated media may require a larger side opening. Follow the instruc-
tions supplied with that accessory for side opening requirements. Do
not cut the opening larger than the dimensions shown in Figure 6.
DANGER
An overpressure protection device, such as a pressure regulator,
must be installed in the gas piping system upstream of the furnace
and must act to limit the downstream pressure to the gas valve so it
does not exceed 0.5 PSI (14" w.c., 3.48 kPa). Pressures exceeding
0.5 PSI (14” w.c., 3.48 kPa) at the gas valve will cause damage to the
gas valve, resulting in a fire or explosion or cause damage to the fur-
nace or some of its components that will result in property damage
and loss of life.
FIGURE 8:
Gas Valve
IMPORTANT:
Plan your gas supply before determining the correct
gas pipe entry. Use 90-degree service elbow(s), or short nipples and
conventional 90-degree elbow(s) to enter through the cabinet access
holes.
!
INLET
WRENCH
BOSS
INLET
PRESSURE
PORT
ON
OFF
ON/OFF SWITCH
(Shown in ON position)
MAIN REGULATOR
ADJUSTMENT
OUTLET
OUTLET
PRESSURE
PORT
VENT PORT
A0226-001
