6
Fig. 8 — Horizontal Units with Mixing Box Option
4. Place mixing box assembly onto frame rail. For units with
1-in. and 2-in. filters, mount mixing box flush to the outer
edge of the end base rail, for units with 4-in. filters, the
mixing box will over-hang the base rail by 2-in. Slide duct
flanges of box over the flanges of the filter frame. It may
be necessary to remove factory-installed sheet metal
screws to enable access to all mounting holes and to
ensure proper fit. Do not remove screws unless necessary.
Secure base rail to mixing box with supplied #8 x
1
/
2
-in.
sheet metal screws, two per side (as shown in Fig. 9).
For bottom-entering configurations, length adjustments to
the bottom damper shaft may need to be completed prior
to final placement of the mixing box.
Fig. 9 — Horizontal Units with Mixing Box Option
5. Secure the mixing box to the filter frame using the sup-
plied #8 x
1
/
2
-in. sheet metal screws at the mounting hole
located at the center of each duct flange. Seal the connec-
tion between the mixing box and the return duct flange
with appropriate tape/sealant product. Be careful not to
tape or seal the filter access panel.
INLET AND OUTLET DAMPERS INSTALLATION
1. Install actuator per manufacturer's instructions.
2. Adjust damper shafts outward to extend past any obstacles
that might cause interference. Do not adjust inward end of
shaft within a distance of 2 inches of bronze bushing.
3. Position inlet damper and outlet damper to coincide with
current or intended position of actuator arm, depending on
actuator's position (opened/closed). Note rotation direction
of each damper.
4. Install crank arms to each damper shaft approximately par-
allel to each other while maintaining state/position of
dampers, as show in Fig. 10. Check for range of motion
clearances before tightening.
Fig. 10 — Install Crank
5. Install swivels to crank arms and hand tighten. See Fig. 11.
Fig. 11 — Install Swivels
6. Insert
5
/
16
-in. damper rod through mounting hole of each
swivel, as shown in Fig. 12. Position shaft to ensure there
is not interference at any point during travel. Tighten rod
clamp of swivel onto each damper rod.
Fig. 12 — Install Damper
7. Confirm correct operation of dampers. Adjust as needed.
Tighten remaining fasteners.
DETAIL A
SEE DETAIL A
DETAIL A
SEE DETAIL A
42DH WITH 2" FILTER FRAME
42DH WITH 4" FILTER FRAME
SEE DETAIL B
SEE DETAIL A
SEE DETAIL A
DETAIL A
