Slant/Fin Caravan LDWO-1100-3-6 Application Manual page 8

a) Starting with modules in the section furthest from the
chimney, count the number of modules venting into that
section of breeching.
b) Find breeching necessary to vent these boilers.
c) Count the modules venting into the next section. To this
figure add the number of modules from the preceding
section, since their output also moves through the second
section.
d) Find the correct size breeching for the second section.
e) Repeat steps (c) and (d) for each section until breeching
for the entire battery has been sized.
f) If the system has more than one battery, repeat steps (a)
through (e) for each battery.
g) Where multiple breeching runs are required, a section of
common breeching is often used to join the multiple runs to
the chimney. To determine the size of this piece, add up
the total number of modules feeding it, and then refer to
Table 2 or chimney manufacturer's data.
h) Find the lengths of the various sections of breeching
needed for a particular job from Table 2.
i) To calculate the length of the battery-to-chimney breeching
section, use the method applicable to the type of breeching
Figure 9. Suggested venting system constructions
as follows:
• Breeching for only one boiler battery. Measure the
distance between the chimney and nearest boiler. Add
this to the figure obtained in step (h).
• Breeching to multiple runs. Measure the distance
between the chimney and the first module of the boiler
battery that is in the same axis as the common
breeching. This is the length of common breeching,
measure the distance between side of the common
breeching and nearest boiler. Add this to the figure
obtained in step (h).
j) To determine the required chimney dimensions, total the
number of modules in the system and refer to Table 3.
Where building height exceeds the recommended
minimum chimney height, refer to chimney paragraph.
NOTE: These procedures DO NOT take into account all
possible field conditions. As with all generalized sizing
information, the final specifications should be tempered with
the engineer's practical experience, and the chimney
manufacturer's data, and ASHRAE Handbook.
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