SYSTEM OPERATION
17
installation using down – venting, an alternate combustion
air opening can be used. A locating dimple is located on
the right side of the furnace cabinet. The locating dimple
is 1 7/8" measured from the front edge of the cabinet in
line with the knock out. To use the alternate combustion
air location:
1. Remove screws and combustion air flange from cabinet.
2. Insert cabinet plug in unused combustion air hole.
3. Drill a pilot hole at the cabinet dimple (size indicated by
knockout tool used).
4. Use a knockout tool to create a 3" diameter hole
5. Install combustion air flange and secure with screws
removed in step one.
6. Install screws removed in step 1 securing flange to
cabinet.
NON-DIRECT VENT (SINGLE PIPE) PIPING
Non-direct
vent
installations require only a vent/flue pipe. The
vent pipe can be run horizontally with an exit through the side
of the building or run vertically with an exit through the roof
of the building. The vent can also be run through an existing
unused
chimney; however, it must extend a minimum of 12
inches above the top of the chimney. The space between
the vent pipe and the chimney must be closed with a weath
-
er-tight, corrosion-resistant flashing.
Although
non-direct
vent
installations do not require a com
-
bustion air intake
pipe
, a minimum of one 90° elbow should be
attached to the furnace’s combustion air intake
if
: an upright
installation uses the standard intake location, or a horizontal
installation uses the alternate air intake location. This elbow
will guard against inadvertent blockage of the air intake.
VENT / FLUE PIPE LENGTHS AND DIAMETERS
NOTE:
For installations at or above 7,000 feet altitude, use
3” venting. If either a 90 degree or 45 degree elbow is used
for termination, it must be pointed downward.
Refer to the following table for applicable length, elbows, and
pipe diameter for construction of the vent/flue pipe system of
a non-direct vent installation. In addition to the vent/flue pipe,
a single 90° elbow should be secured to the combustion air
intake to prevent inadvertent blockage. The tee used in the
vent/flue termination must be included when determining the
number of elbows in the piping system.
1. Maximum allowable limits listed on individual lengths for
inlet and flue and NOT a combination.
2. Minimum requirement for each vent pipe is five (5) feet in
length and one elbow/tee.
3. Tee used in the vent/flue termination must be included
when determining the number of elbows in the piping
system.
4. 2 ½” or 3” diameter pipe can be used in place of 2” diam
-
eter pipe.
5. Increased Clearance Configurations using (2) 45 deg.
Long Sweep elbows should be considered equivalent to
one 90 degree elbow.
NON-DIRECT VENT INSTALLATIONS
A minimum of one 90° elbow should be installed on the
combustion air intake “coupling” to guard against inadvertent
blockage.
ALTERNATE VENT / FLUE LOCATION
The alternate vent / flue location is the large hole directly
in
line with the induced draft blower outlet. To use the alternate
vent / flue location refer to the following steps and the “Alter
-
nate Vent / Flue Location” figure. This option is not available
with counter-flow models.
NOTE
: In the horizontal left installation position, a means of
condensate collection must be provided to keep vent pipe
condensate from entering the draft inducer housing. If the vent
drain elbow is eliminated from the installation, an RF000142
kit must be used.
1. Remove the four screws from the vent pipe flange on top
the furnace.
2. Remove the internal elbow and vent pipe.
3. Cut 2 ½" from the flange.
4. Remove plastic plug in line with the inducer outlet
5. Install cut end of the flanged section and connect to
inducer with rubber coupling supplied with furnace.
6. Install screws removed in step 1 securing flange to cabinet.
B
E
SURE
NOT
TO
DAMAGE
INTERNAL
WIRING
OR
OTHER
COMPONENTS
WHEN
REINSTALLING
COUPLING
AND
SCREWS
.
CAUTION
ALTERNATE COMBUSTION AIR PROVISION
(Upflow / Horizontal models only)
When using the alternate venting location, either in
a horizontal left side down installation or a vertical
1
2
3
4
5
6
7
8
2 or 2 1/2
115
110
105
100
95
90
85
80
3
137
130
123
116
109
102
95
88
2 or 2 1/2
115
110
105
100
95
90
85
80
3
147
140
133
126
119
112
105
98
2 or 2 1/2
60
55
50
45
40
35
30
25
3
120
113
106
99
92
85
78
71
2 or 2 1/2
40
35
30
25
20
15
10
5
3
144
137
130
123
116
109
102
95
2 or 2 1/2
40
35
30
25
20
15
10
5
3
144
137
130
123
116
109
102
95
2 or 2 1/2
95
90
85
80
75
70
65
60
3
144
137
130
123
116
109
102
95
2 or 2 1/2
95
90
85
80
75
70
65
60
3
144
137
130
123
116
109
102
95
2 or 2 1/2
60
55
50
45
40
35
30
25
3
120
113
106
99
92
85
78
71
2 or 2 1/2
40
35
30
25
20
15
10
5
3
103
96
89
82
75
68
61
54
Direct Vent (2 - Pipe) and Non-Direct Vent (1- Pipe)
(6)
Pipe
Size
Model
Number of Elbows
*MVM970603BNA*
*MVM970803BNA*
*MVM970804CNA*
*MVM971005CNA*
*CVM971005CNA*
*MVM971205DNA*
*CVM970603BNA*
*CVM970803BNA*
*CVM970804CNA*
