Install Instructions

50 103448-08- 9/16
IV. Venting F. Multiple Boiler Installation Venting
WARNING
Asphyxiation Hazard. No common manifold venting (vent piping and vent terminals) is permitted.
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.
1. Vent Piping and Terminations
a. Multiple boiler vent terminations are shown in
Figure 18.
b. Each individual boiler must have its own vent
pipe and vent terminal. Refer to Paragraphs A
through E (as applicable) for individual boiler
vent guidelines and options.
c. Do not exceed the individual boiler maximum
vent length listed in Table 5A.
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.
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.
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 18.
b. Each individual boiler must have own
combustion air pipe and terminal. Refer to
Paragraphs A through E (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 5A.
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.
F. Multiple Boiler Installation Venting