MGI Modular Gravity Hood with Filters
(throat sizes 78" & larger)
INSTALLATION & ASSEMBLY MANUAL
See Catalog 4720 for sizes that ship assembled.
IM-4720FSL
August 2013
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40 Cap Screw, Serrated Flange, 1/4-20 x 5/8"
40 Hex Nut, Serrated Flange, 1/4-20
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4 Doubler plates
4 Cap Screw, Serrated Flange, 5/16-18 x 3/4"
4 Hex Nut, Serrated Flange, 5/16-18
Note: Not always required.
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8 Cap Screw, Serrated Flange, 5/16-18
8 Hex Nut, Serrated Flange, 5/16-18
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40 Screws, 12 x 3/8"
Hardware Kit #1B
Item
Hardware Kit #1C
Item
Hardware Kit #3
Item
Hardware Kit #4A
Item
Figure 1.
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60 Screws, 12 x 3/8"
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88 Screws, 12 x 3/8"
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A/R Hood Clips (Only for hood panels longer than 108")
Qty
28 Cap Screw, Serrated Flange, 5/16-18 x 3/4"
28 Hex Nut, Serrated Flange, 5/16-18
Hardware Kit #4B
Item
Hardware Kit #4C
Item
Hardware Kit #5
Item
Hardware Kit #6B
Item
Hood End Panel
Assembly (Female Rib)
Hood Panel
Hood Support Assembly
Side Filter
Hood End Panel
ssembly (Male Rib)
Hood Rail Assy
End Filter
Filter Rail, Type -C-
Filter Stop Plate
Stiffener Angle
Filter Rail, Type -B-
©2013 Twin City Fan Companies, Ltd.
Base Assy
Hood Mount Bar
Filter Rail, Type -A-
Step 1 – Base Assembly
Fasteners (Kit #1B and #1C) – Note: There may be extra fasteners.
Lay out the Curb Base Side, Hood Support Assembly and Curb Base End in approximate location to each other. See
Figure 2. Use (3) 1/4-20 fasteners for 5" base height and (4) 1/4-20 fasteners for 12" base height. Leave top two
holes open on the Base End. Note: Hand tighten only until Step 3. Bolt together Curb Base Sides to Hood Support
Assembly with (8) 1/4-20 fasteners per Hood Support Assembly for 5" bases and (10) 1/4-20 fasteners for 12" bases.
On some hoods, a Doubler Plate is required. See Detail A of Figure 2. For base assemblies with more than one
Hood Support Assemblies, orient top flanges away from center.
Figure 2.
Curb Base Side
Hood Support Assembly
Curb Base Side
Curb Base End
Screw
Hex Nut
Curb Base End
Curb Base Side
Curb Base Side
Doubler Plate
DETAIL A
* When Kit 1C provided.
Step 2 – Hood Mount Bars
Fasteners (Kit #1B and #1C)
Loosely assemble Hood Mount Bars on both sides of the Base Ends using (4) 1/4-20 fasteners per side. On hoods
using a Doubler Plate, mount Brace using 5/16-18 hardware. See Figure. 3b.
Figure 3a. Figure 3b.
Hood Mount Bar
Hood Mount Bar
Brace
Step 3 – Caulk
Caulk inside corners of base assembly and tighten all fasteners. Install assembly onto roof curb before proceeding.
Ensure that assembly is properly anchored to roof curb.
Step 4 – Filter Rails
Fasteners (Kit #6B) – Note: There may be
extra fasteners.
Attach Filter Channel, Type -A- to the
Hood Mount Bar using cap screws and
nuts (hand tight). Lay Filter Channel,
Type -B- onto assembly and wedge Filter
Stop Plate between them and the Base
Assembly. Assemble with cap screws and
nuts (hand tight).
2 Twin City IM-4720FSL
Figure 4.
Filter Rail, Type -B-
Filter Rail, Type -A-
Screw, Flanged Head
Filter Stop Plate
Base Assy