Thermal Solutions APEX APX425C Installation, Operating And Service Instructions page 37

4
Venting
(continued)
c. Do not exceed the individual boiler
maximum vent length listed in Table 4-2.
d. For horizontal sidewall terminations,
maintain at least 12 in. (300 mm) minimum
horizontal distance between any adjacent
individual boiler vent terminations.
Additional horizontal spacing between any
adjacent individual boiler vent terminations
as well as extending the distance from
building surfaces to vent termination end
are recommended to avoid frost damage to
building surfaces where vent terminations
are placed.
NOTICE: Installing multiple individual boiler vent
terminations too close together may result in
combustion product water vapor condensation
on building surfaces, where vent terminations are
placed, and subsequent frost damage. To avoid/
minimize frost damage, extend the distance from
building surfaces to vent termination end and
increase the horizontal distance between adjacent
vent terminations.
e. Individual boiler sidewall vent terminals
must be placed at least 12 in. (300 mm) [18
in. (460 mm) in Canada] above the ground
plus the expected snow accumulation.
106308-05 - 3/23
APEX Installation, Operating, & Service Instructions
f. Multiple individual boiler vertical vent pipes
may be piped through a common conduit or
chase so that one roof penetration may be
made.
g. For vertical roof terminations, maintain at
least 12 in. (300 mm) minimum horizontal
distance between adjacent individual boiler
vent terminations.
2. Combustion Air Piping
a. Multiple boiler combustion air terminations
are shown in Figure 4-34.
b. Each individual boiler must have own
combustion air pipe and terminal. Refer to
Paragraphs A through F (as applicable) for
individual boiler combustion air guidelines
and options.
c. Do not exceed the individual boiler
maximum combustion air pipe length listed
in Table 4-2.
d. If possible, locate vent and combustion
air terminals for an individual boiler on the
same wall to prevent nuisance shutdowns.
If not, an individual boiler may be installed
with a roof vent terminal and sidewall
combustion air terminal.
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