HTP Hydra Smart RT-199, User Manual

Page: 34 / 73

lp-505 Rev. 000 Rel. 015 Date 1.7.20
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I. Common Vent Piping - 199 Model in Cascade Applications Only!
These units can be common vented. Connecting several units together
requires proper sizing of the intake and exhaust pipes. Up to eighteen
(18) units can be common vented together.
Common Vented units must be direct vented, with an exhaust vent
and intake air pipe vented to the outdoors. DO NOT power vent
Common Vented units! Doing so will result in property damage,
severe personal injury, or death.
1. Vent Diameter Sizing and Lengths
These units are designed for 3 inch exhaust vent and intake pipes. The
following chart outlines the maximum length of common venting
allowable. A vent system’s length is calculated by adding the length
of all straight pieces used (both horizontal and vertical) and then
adding the equivalent lengths of each fitting used in the system. A
vent system’s length must not exceed the maximum length outlined
in the chart below.
Maximum Vent Length (in Ft.) for Direct Vent (2 Pipe)
Number of Units
Common Vented
Load
(BTU/Hr)
Pipe Size
3” 4” 6” 8” 10” 12”
1 199,000
100 100
N/A
N/A
N/A
N/A
2 398,000
50 83
3 597,000
N/A
58 133
4 796,000
N/A
101
5 995,000 75
6 1,194,000 67 117
7 1,393,000 58 99
8 1,592,000
N/A
89
9 1,791,000
79 124
10 1,990,000
71 110
11 2,189,000
65 101
12 2,388,000 59 92
13 2,587,000
N/A
86
14 2,786,000 79 114
15 2,985,000 74 107
16 3,184,000
70 101
17 3,383,000
65
N/A
18 3,582,000
62
Table 20 - Maximum Common Vent Length for Direct Vent (2 Pipe)
NOTE:
Reduce the maximum equivalent length above by 5 feet per
90
o
elbow used and by 2 feet per 45
o
elbow used. DO NOT exceed the
above set limits.
DO NOT ATTEMPT to common vent 150 model water heaters! Doing
so will result in property damage, severe personal injury, or death.