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WARNING
In addition to preventing
ingestion of chemical
contaminants, care must
be taken to ensure air
intake terminals are not
installed in locations where
contamination might occur
due to ingestion of particulate
foreign material (dust, dirt
and debris).
WARNING
Intake air openings must be
configured such that rain
or other forms of moisture
cannot enter the air intake
piping system. Otherwise
serious damage to the boiler
may result.
NOTE
Care must be taken when
installing air intake piping to
ensure that a "trap" is not
formed in the piping so as to
allow a build-up of water, and
blockage of intake air.
Such blockage will result in a
boiler safety shut-down.
1-14
HC SERIES BOILERS HC 13-50, HC 15-95, HC 15-96, HC 20-125, HC 33-160
Figure 14B: Distance Inside / outside minimums
1.4.7 "Direct Vent" Combustion Air Intake Piping
The boiler must always be installed as a Direct Vent venting system with the
combustion air piped directly from the outdoors to the boilers combustion air
connection. Provisions for combustion and ventilation air in accordance with
the section "Air for Combustion and Ventilation," of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54, or Clause 8.2, 8.3 or 8.4 of Natural Gas and Propane
Installation Code, CAN/CSA B149.1, or applicable provisions of the local building
codes.
Figure 15: Direct vent combustion air intake
For 3" Flexible PPs, up to 35 actual lineal feet are allowed in a nominally vertical
orientation (>45°). The equivalent length of 3" Flexible PPs shall be computed
using a multiple of 1.4:1, e.g. 35' x 1.4 = 49' equivalent. The balance of the
venting allowance is still available for use with rigid PPs piping material. 2"
Flexible PPs is not allowed.
INSTALLATION AND OPERATION INSTRUCTIONS
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