PG80VTLA: 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
 
HORIZONTAL INSTALLATION 
The  furnace  can  be  installed horizontally  in  an  attic  or  crawlspace  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 Fig. 14 and Fig. 15). 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.
screws into the side and 2 #8 x in. screws in the bottom of the furnace
casing for each strap. (See Fig. 14 and Fig. 15).
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 Fig. 2 and Fig. 13). For furnaces with 1-in. (25
mm)  clearance  requirement  on  side,  set  furnace  on  non-combustible
blocks, bricks or angle iron. For crawlspace 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. 
A10164
Fig. 13 – Typical Attic Installation
Table 3 – Opening Dimensions - In. (mm)
FURNACE 
CASING 
WIDTH 
APPLICATION 
PLENUM OPENING  FLOOR OPENING 
A  B  C  D 
14–3/16
(360)
Upflow Applications on Combustible or Noncombustible Flooring (subbase 
not required) 
12-11/16
(322) 
21-5/8
(549) 
13-5/16
(338) 
22-1/4
(565)
Downflow Applications on Noncombustible Flooring
(subbase not required) 
12-9/16
(319) 
19
(483) 
13-3/16
(335) 
19-5/8
(498) 
Downflow Applications on Combustible Flooring
(subbase required) 
11-13/16
(284) 
19
(483) 
13-7/16
(341) 
20-5/8
(600) 
Downflow Applications on Combustible Flooring with Cased Coil (subbase 
not required) 
12-5/16
(319) 
19
(483) 
13-5/16
(338) 
20
(508)
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 Cased Coil (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 Cased Coil (subbase 
not required) 
19
(483)
19
(483) 
20
(508) 
20
(508)
24-1/2
(622) 
Upflow Applications on Combustible or Noncombustible Flooring (subbase 
not required) 
23
(584) 
21-1/8
(537) 
23-5/8
(600) 
22-1/4
(565) 
Downflow Applications on Noncombustible Flooring 
(subbase not required) 
22-7/8
(581) 
19
(483) 
23-1/2
(597) 
19-5/8
(498) 
Downflow Applications on Combustible Flooring 
(subbase required) 
22-1/8
(562) 
19
(483) 
23-3/4
(603) 
20-5/8
(600) 
Downflow Applications on Combustible Flooring with Cased Coil (subbase 
not required) 
22-1/2
(572) 
19
(483) 
23-1/2
(597) 
20
(508)
WARNING
!
FIRE, EXPLOSION, AND CARBON MONOXIDE 
POISONING HAZARD
Failure to follow this warning could result in personal injury, death, 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. 
30-IN. (762mm) 
MIN WORK AREA
6″ MIN*
TYPE-B
VENT
17 
3
/4
″
22
″
SHEET
METAL
SEDIMENT
TRAP
EQUIPMENT MANUAL
SHUT-OFF GAS VALVE
LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS, OR FRAMING.
GAS
ENTRY
17 
3
/4
″ 
(451mm)
OVERALL
4 
3
/4
″ 
(121mm) 
UNDER DOOR
1″ 
(25mm) 
UNDER   FURNACE
EXTEND OUT 12″ 
(305mm)
FROM FACE OF DOOR
* WHEN USED WITH
SINGLE WALL VENT
CONNECTIONS
UNION
(152mm)
(451mm)
(559mm)