Allied 80G2DFE, Installation Instructions Manual

508145-01

Issue 2128

Page 9 of 36

RIGID LEG

remove shipping bolt and washer

Units with 1/2 or 3/4 HP Blower Motor

Figure 7. 

The  blower  access  panel  must  be  securely  in  place 

when the blower and burners are operating. Gas fumes, 

which  could  contain  carbon  monoxide,  can  be  drawn 

into living space resulting in personal injury or death.

 WARNING

Downflow Installation

Downflow unit installs in three ways: on non-combustible 

flooring,  on  combustible  flooring  using  a  downflow 

combustible  flooring  base,  or  on  a  reverse-flow  cooling 

cabinet. Do not drag the unit across the floor.

Installation on Non-Combustible Flooring

(Figure 8)

1.  Cut  floor  opening  keeping  in  mind  clearances  listed 

on  unit  rating  plate.  Also  keep  in  mind  gas  supply 

connections,  electrical  supply,  flue  and  air  intake 

connections  and  sufficient  installation  and  servicing 

clearances. See Table 1 for correct floor opening size.

2.  Flange warm air plenum and lower the plenum into the 

opening.

3.  Set the unit over the plenum and seal the plenum to 

the unit.

4.  Ensure that the seal is adequate.

Figure 8.  

              UNIT

SUPPLY AIR

PLENUM

OPENING

Cabinet 

Width

Front to Rear

Side to Side

in

mm

in

mm

A (14-1/2”)

19-3/4

502

13-1/4

337

B (17-1/2”)

19-3/4

502

16-1/4

413

NOTE - Floor opening dimensions listed are 1/4 inch (6 mm) 

larger than the unit opening. See unit dimensions on Page 

2.

Table 1. 

Non-Combustible Floor Opening Size

Installation on Combustible Flooring  

(Figure 9)

1.  When  unit  is  installed  on  a  combustible  floor,  a 

downflow combustible flooring base must be installed 

between the furnace and the floor. The base must be 

ordered  separately.  See Table  2  for  opening  size  to 

cut in floor.

2.  After opening is cut, set combustible flooring base into 

opening.

3.  Check sealing strips on combustible flooring base to 

make sure they are properly glued and positioned.

4.  Lower  supply  air  plenum  into  downflow  combustible 

flooring  base  until  plenum  flanges  seal  against  the 

strips.

NOTE: 

Be careful not to damage sealing strips. Check 

for a tight seal.

5.  Set the furnace over the plenum.
6.  Ensure that the seal between the furnace and plenum 

is adequate.

The  furnace  and  downflow  combustible  flooring  base 

shall not be installed directly on carpeting, tile, or other 

combustible material other than wood flooring.

 IMPORTANT

Figure 9.  

UNIT

SUPPLY AIR PLENUM

DOWNFLOW

COMBUSTIBLE

FLOORING BASE

PROPERLY

SIZED FLOOR

OPENING