650.65-N2
When the return duct system is not complete, the return con
nection must be run full size from the furnace to a location
outside the utility room or basement. For further details, consult
Section
5.3,
Air C ombustion and Ventilation of the National Fuel
Gas
Code,
ANSI
Z223.1
or
CAN1-B149.1
or
.2
Installation
Code (latest editions).
FILTERS
The type and s ize of filter(s) to
be
used are shown in Table
1.
12-1/4
&
1&-1/4
Inch Width Furnaces
All12-1/4
&
16-1/4 inch wide furnaces are ship ed with filters
mounted on the left side. Filters may
be
relocated to the bottom
or right side as follows:
The wire filter retainer must
be
moved if the return air applica
tion requires moving of the filter from the side to the bottom
location or vice versa. When relocating filters,
it
may
be
nec
essary to trim the filter to the proper size.
·""
SlOE
APPUCATION
BOTTOM
.APPUCA TION
METAL
lOOPS
RGURE 2
-FILTER RETAINER
ffiONT
RETAINER
The ends of the retainer are attached to the rear panel in two
metal loops (See
2). The ends must
be
squeBzed
·
together to free them
the loops. The retainer may then be
moved to the new location, and the ends inserted in the
on
the rear panel at the new location. Loops are provided
retainer location to accommodate filter application on the bot
tom or either side of the furnace.
TABLE 2-
COMBUSTION
AIR/VENT PIPE SIZES
MODEL
Pipe
Size
o-5
feet
PBNU-LD06P040/PBNU-L006N040
1-1/2"
5
2"
5
PBNU-LD1 OP060/PBNU-LD 1 ON060
1-1/2"
3
2"
5
PBNIJ-LD12P0801PBNU-LD12N080
2"
5
3"
5
PBNU-LD16P080/PBNU-LD16N080
2"
5
3"
5
PBNU-LD12P 1 OOIPBNU-LD12N100
2"
5
PBNU-LD20P 1 OO/PBNU-LD20N100
2"
5
PBNU-LD16P1201PBNU-LD16N120
3"
5
PBNU-LD20P140/PBNU-LD20N140
3"
5
To remove a filter from the bottom location, push the closed end
of the fitter retainer to the left until
it
clears the lip on the front
of the furnace base, which acts as a catch for the retainer.
Wben the retainer is clear of the lip, lift up. The retainer will pivot
in the loops. This· will expose the filter to allow removaL To
reinstall the filter, simply reverse this procedure.
To remove a filter from the side location, push the closed end
of the filter retainer down until it clears the flange on the side
panel, which acts as a catch for the retainer. When the retainer
is clear of th-e flange, it will pivot in the loops.._ Swing the retainer
toward the center of th\3 furnace. This will expose the filter to
allow removal. To reinstall the filter, simply reverse this proce-
dure.
22-1/4
&
2&-1/4
Inch Width Furnaces·
22-1/4
&
26-1/4
inch wide furnaces are shipped with filters
·
mounted in the bottom and left side.
For filter removal in these models, follow the same procedure
as with the small width furnaces.
COMBUSTION AIRNENT PIPE SIZING
Refer to Table 2 to select the proper size
for combustion
air intake and venting. The size will
be
by a com
bination of furnace model, total length of run, and the number
of elbows required. The following rules must also
be
observed.
1.
Long radius elbows are recommended for all units except
for
the
133
MBH
unit forvvhich
bng
radius
elbows
are mandatory
2.
Elbows are assumed to be
90
degrees. Two
45
degreB
elbows count as one
90
degree elbow.
3.
Elbow count refers to com bust ion air piping and vent piping
separately. For example, if the table allows for
5
elbows,
this will allow a maximum of
5
elbows in the combustion
air piping and a maximum of
5
elbows in the vent piping.
5.
Combustion· air and vent piping must
be
of the same
diameter.
6.
All piping and fittings are to be
Schedule 40
PVC, PVC
DVVV, ABS-DVVV, SDR-21
PVC, or
SDR-26
PVC.
COMBUSTION AIR INTAKE
MAXIMUM ELBOWS PER TOTAL
Note
s-1o
feet
1G-15 feet 15-20 feet 2G-25
feet
25-30 feet 30·35 feet
4
3
2
Note 1
Note 1
Note 1
5
5
5
5
5
5
2
Note 1
Note 1
Note 1
Note 1
�Note 1
5
5
5
5
5
5
4
3
2
1
Note 1
Note 1
5
5
5
5
5
5
4
3
2
1
Note 1
Note 1
5
5
5
5
5
5
5
5
5
5
5
30'Max
5
5
5
5
5
30'Max
5
5
5
5
5
5
5
5
5
5
5
30'Max.
NOTES:
1. Must use the
larger
pipe size indicated
2.
Long
radius elbows recommended
on
these
units,
except 140
MBH,
when over 25 feet of p
i
p
ing is required. On
140
MBH
units, use of long radius elbows is
mandatcxy.
