Modine Manufacturing HD Installation And Service Manual page 8

INSTALLATION
must be sealed with metallic tape or silastic suitable for
temperatures up to 400°F. Wrap tape two full turns around
the vent pipe joint. One continuous section of double wall
vent pipe may be used with the vent system.
2. The maximum length of the horizontal run of the vent shall
be limited to the length listed in Table 8.1. The vent terminal
for a horizontal category I vent may be either a standard
vent TEE, a Gary Steel 1092 or a Breidert Type L style cap.
The maximum number of elbows, slope of the horizontal
section, and minimum vertical rise from horizontal vent pipe
for each configuration is listed in Table 8.1.
A. When using a standard vent TEE, the preferred
orientation of the TEE is for the open ends of the
TEE to be oriented horizontally. In this orientation, the
minimum clearance to combustibles is 6" above the
TEE to the eave. If the TEE is oriented vertically, the
minimum clearance to combustibles is 27" above the
TEE to the eave. Refer to Figure 9.1. The vent TEE
should incorporate a bird screen made from corrosion
resistant material. The individual strands
of mesh in the bird screen must be located at least
1/4" apart.
B. When using a vent cap, the minimum clearance to
combustibles is 6" above the cap to the eave. Refer to
Figure 9.1.
Table 8.1
Allowable Vent Configurations for Category I Horizontal Venting
Model Vent
Size Terminal
30 Vent TEE
Vent Cap
Vent TEE
Vent Cap
Vent Cap
45 Vent TEE
Vent Cap
Vent Cap
60
Vent TEE
Vent Cap
75 Vent TEE
Vent Cap
①
One of the two allowed elbows is required to create the vent extension shown in figures 9.3 and 9.4.
②
The vertical rise gained from an elbow is 4". Therefore, 4" may be subtracted from the length of vertical
pipe needed in the vent extension. If the minimum vertical rise required is 4" you do not need to add a
section of vertical pipe to the vent extension.
8
Maximum No. Minimum Vertical
Elbows Rise From
Horizontal (in)
1
2 ①
1
2 ①
2 ①
1
2 ①
2 ①
1
2 ①
1
2 ①
4. When vented horizontally, maintain a 1/4" per foot rise
away from the heater. Place a drain tee and clean out near
the vent connector. See Figures 8.1 and 9.3. Where local
authorities have jurisdiction, a 1/4" per foot downward slope
is acceptable. The Condensate is allowed to drip out of
the end when using a TEE terminal. See Figure 9.2. When
using a vent cap with an extension, a 3/8" diameter hole is
drilled in the low point of the vent by the installer exterior to
the space to allow condensation drainage. See Figure 9.4.
Figure 8.1
Horizontal Category I Venting -TEE With Upward Pitch
Exterior wall
Vent tee
12" Min
Listed thimble
Clean out/Drip leg
Maximum vent length (B)
Maximum
Horizontal Vent
Length (ft)
(A) (B)
0 10
4 ② 10
0 5
12 ② 5
18 ② 10
0 10
12 ② 10
18 ② 5
0 10
15 ② 10
0 5
18 ② 5
6-576.5
1/4" Slope up
towards termination
Vent transition
Vent
Diameter (in)
5
5
4
4
4
5
5
4
5
5
5
5