![background image](http://html1.mh-extra.com/html/carrier/pg80msu/pg80msu_installation-start-up-operating-and-service-and-maintenance-instructions_2563007010.webp)
PG80MSU: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
10
Table 4 – Opening Dimensions - In. (mm)
Horizontal Installation
The furnace can be installed horizontally in an attic or crawl space on
either the left-hand (LH) or right-hand (RH) side. The furnace can be
hung from floor joists, rafters or trusses or installed on a
non-combustible platform, blocks, bricks or pad.
Suspended Furnace Support
The furnace may be supported under each end with threaded rod, angle
iron or metal plumber’s strap as shown, see
. Secure
angle iron to bottom of furnace as shown. Heavy-gauge sheet metal
straps (plumber’s straps) may be used to suspend the furnace from each
bottom corner. To prevent screws from pulling out, use 2 #8 x 3/4-in. (19
mm) screws into the side and 2 #8 x 3/4-in. (19 mm) screws in the
bottom of the furnace casing for each strap, see
. If
the screws are attached to ONLY the furnace sides and not the bottom,
the straps must be vertical against the furnace sides and not pull away
from the furnace sides, so that the strap attachment screws are not in
tension (are loaded in shear) for reliable support.
Platform Furnace Support
Construct working platform at location where all required furnace
clearances are met, see
. For furnaces with 1-in. (25
mm) clearance requirement on side, set furnace on noncombustible
blocks, bricks or angle iron. For crawl space installations, if the furnace
is not suspended from the floor joists, the ground underneath furnace
must be level and the furnace set on blocks or bricks.
A180240
Fig. 14 – Typical Attic Installation
A10130
Fig. 15 – Horizontal Unit Suspension
Roll-Out Protection
Provide a minimum 17-3/4 in. x 22 in. (451 mm x 559 mm) piece of
sheet metal for flame roll-out protection in front of burner area for
furnaces closer than 12 inches (305 mm) above the combustible deck or
suspended furnaces closer than 12 inches (305 mm) to joists. The sheet
metal MUST extend underneath the furnace casing by 1 in. (25 mm)
with the door removed.
The bottom closure panel on furnaces of widths 17-1/2 in. (445 mm) and
larger may be used for flame roll-out protection when bottom of furnace
is used for return air connection. See
roll-out shield.
FURNACE
CASING
WIDTH
APPLICATION
PLENUM OPENING
FLOOR OPENING
A
B
C
D
17–1/2
(445)
Upflow Applications on Combustible or Noncombustible Flooring
(subbase not required)
16
(406)
21-5/8
(549)
16-5/8
(422)
22-1/4
(565)
Downflow Applications on Noncombustible Flooring (subbase not
required)
15-7/8
(403)
19
(483)
16-1/2
(419)
19-5/8
(498)
Downflow applications on combustible flooring (subbase required)
15-1/8
(384)
19
(483)
16-3/4
(425)
20-5/8
(600)
Downflow Applications on Combustible Flooring with Coil Assembly or
coil box (subbase not required)
15-1/2
(394)
19
(483)
16-1/2
(419)
20
(508)
21
(533)
Upflow Applications on Combustible or Noncombustible Flooring
(subbase not required)
19-1/2
(495)
21-5/8
(549)
20-1/8
(511)
22-1/4
(565)
Downflow Applications on Noncombustible Flooring (subbase not
required)
19-3/8
(492)
19
(483)
20
(508)
19-5/8
(498)
Downflow applications on combustible flooring subbase required)
18-5/8
(473)
19
(483)
20-1/4
(514)
20-5/8
(600)
Downflow Applications on Combustible Flooring with Coil Assembly or
coil box (subbase not required)
19
(483)
19
(483)
20
(508)
20
(508)
WARNING
!
FIRE, EXPLOSION, AND CARBON MONOXIDE
POISONING HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Do not install the furnace on its back or hang furnace with control
compartment facing downward. Safety control operation will be
adversely affected. Never connect return-air ducts to the back of the
furnace.