Installation Guide

21
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 dictated 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.
VENT/FLUE PIPE LENGTHS AND DIAMETERS
Refer to the following table for applicable length, elbows, and pipe
diameter for construction of the vent/flue pipe system. The tee
used in the vent/flue termination must be counted as an elbow
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 determin-
ing the number of elbows in the piping system.
4) 2 1/2” or 3” diameter pipe can be used in place of 2” diameter pipe.
5) Increased Clearance Configurations using (2) 45 deg. elbows should
be considered equivalent to one 90 deg. elbow.
6) One 90° elbow should be secured to the combustion air intake connection.
VENT/FLUE PIPE TERMINATIONS
NOTE: If either a 90 degree or 45 degree elbow is used for termination, it must be pointed downward.
The vent/flue pipe may terminate vertically, as through a roof, or horizontally, as through an outside wall.
Vertical vent/flue pipe terminations should be as shown in the following figure. Refer to Vent/Flue Pipe and Combustion Air Pipe -
Termination Locations for details concerning location restrictions. The penetration of the vent through the roof must be sealed tight
with proper flashing such as is used with a plastic plumbing vent.
Horizontal vent/flue pipe terminations should be as shown in the following figure. Refer to Vent/Flue Pipe and Combustion Air Pipe
- Termination Locations for details concerning location restrictions. The wall penetration should be sealed with silicone caulk-
ing material.
NOTE: Terminate both pipes in the same pressure zone (same side of roof, no major obstacles between pipes, etc.).
012345678
60,000
2
or 2 1/2
250 245 240 235 230 225 220 215 210
80,000
2
or 2 1/2
250 245 240 235 230 225 220 215 210
80,000 3 250 243 236 229 222 215 208 201 194
100,000
2
or 2 1/2
90 85 80 75 70 65 60 55 50
100,000 3 250 243 236 229 222 215 208 201 194
120,000
2
or 2 1/2
75 70 65 60 55 50 45 40 35
120,000 3 220 213 206 199 192 185 178 171 164
*MVM97/*CVM97 Direct Vent (2 - Pipe) and Non-Direct Vent (1- Pipe)
(6)
Maximum Allowable Length of Vent/Flue Pipe & Combustion Air Pipe (ft)
(1) (2)
Unit
Input
(Btu)
Pipe Size
(4)
(in.)
Number of Elbows
(3) (5)
COMBUSTION AIR INTAKE
(OPTIONAL)
*Not required for
single pipe installation
TEE (OPTIONAL)
9
6
”
M
A
X
.
-
3
”
M
I
N
.
R
O
O
F
L
I
N
E
INTAKE
SCREEN
OPTIONAL
12” MIN
HEIGHT DIFFERENCE
BETWEEN
INTAKE AND VENT
12” MIN TO ROOF OR HIGHEST
ANTICIPATED SNOW LEVEL
Figure 13
STRAIGHT
ELBOWS
Figure 14