10
ACCESSORY DOWNFLOW SUBBASE
LOCATING
TAB
4321
1234
B
D
LOCATING
TAB
A88207
Disassembled
C
A
1
1
/
4
-in. (70 mm) TYP
PLENUM
OPENING
FACTORY-SUPPLIED
FIELD-INSTALLED
INSULATION
A97427
Assembled
FURNACE
CASING WIDTH
IN. (mm)
FURNACE IN
DOWNFLOW
APPLICATION
PLENUM OPENING*
IN. (mm)
FLOOR OPENING
IN. (mm) HOLE NO. FOR
WIDTH
ADJUSTMENT
AB C D
17---1/2
(445 mm)
Furnace with or
without Cased
Coil Assembly or
Coil Box
15---1/8
(384 mm)
19
(483 mm)
16---3/4
(426 mm)
20---3/8
(518 mm) 3
21
(533 mm)
Furnace with or
without Cased
Coil Assembly or
Coil Box
18---5/8
(473 mm)
19
(483 mm)
20---1/4
(514 mm)
20---3/8
(518 mm) 2
24---1/2
(622 mm)
Furnace with or
without Cased
Coil Assembly or
Coil Box
22---1/8
(562 mm)
19
(483 mm)
23---3/4
(603 mm)
20---3/8
(518 mm) 1
*The plenum should be constructed 1/4 in. (6 mm) smaller in width and depth than the plenum dimensions shown above.
58MXB
