P/N 42-9540 11/12 Copyright 2012 Hydrotherm
Page 6 KN INSTALLATION INSTRUCTIONS FOR VENT AND AIR PIPING
Vent piped through the roof (combustion air from the boiler room) (cont.)1
Table 1 Vent system components
Figure 2 Vent termination minimum clearances
❑Slope horizontal runs toward the boiler. All horizontal runs of vent pipe
must slope continuously at least 1/4 inch per foot (21 mm per meter) to ensure
condensate drains completely back to the boiler. DO NOT install the vent piping
with any sections that could trap condensate.
2 — Vent piping components
❑See Table1 for acceptable vent components. NO OTHER vent materials are
acceptable.
❑Carefully follow the instructions supplied by the vent piping manufacturer.
❑e vent joints seal with elastomer rings in the pipe and ings. Avoid damaging
these seals.
❑Adjustable lengths of EZ-Seal pipe —Lengthadjustmentswith EZ-Seal piping
are made with slip-t adjustable length sections, not by cuing the pipe. Make sure
the adjustable length does not jut into elbows or terminations. is could block
ue gas and condensate ow.
❑Maximum vent piping length — See the table in Figure 3 for the maximum
allowable length. Each elbow causes the same pressure drop as 10 feet of vent pipe,
so the allowable length reduces 10 feet for each elbow used in the piping. When
45° elbows are used, two 45° elbows are equivalent to one 90° elbow.
❑Insulate the vent piping where it passes through unheated areas to prevent
condensate freeze-up.
❑If the pipe passes through an occupied space, install a chase around the pipe,
following the vent pipe instructions and applicable codes.
❑Clearance from combustible materials — Provide minimum clearance to all
combustible materials of at least 2 inches (51 mm).
❑Using an existing chimney as a chase —event piping can beroutedthrough
an existing UNUSED and STRAIGHT chimney. DO NOT vent directly into the
chimney. Install the vent piping so it can be inspected aer installation. Follow vent
pipe manufacturer’s instructions for chimney-as-chase installations.
3 & 4 — Support the vent piping completely
❑DO NOT use the boiler vent connection to support the vent piping. Provide
support straps from the ceiling and pedestal supports from the oor; utilize
noncombustible saddle. is is required on ALL installations, regardless of the
length of the horizontal piping connected to the boiler.
❑Ventpipingcannotbesupportedfromabove(suchasrelyingonroofjacksections).
You must install supports on the horizontal piping before the vent turns upward.
Provide a support on the horizontal piping within 6 inches of every upturned
elbow to support the vertical run.
❑Install at least one support on every horizontal run. For horizontal runs
longer than 5 feet (1.5 m), install a support every 3 feet (0.9 m).
❑Follow the vent pipe manufacturer’s instructions for placement and installation of
supports.
5 — Floor and wall penetrations
❑Followapplicablecodesand the ventpipe instructionstoinstallrestops,thimbles
or other devices at all oor and wall penetrations.
❑Provide minimum 2 inches (51 mm) clearance to all combustible construction.
6 — Roof penetrations
❑Followapplicablecodesandtheventpipeinstructions toinstallaroofjack, ashing
and support. Long extensions of vent pipe above the roof may require the use of
guy supports as specied in the vent pipe instructions.
7 — Rain cap termination
❑Use only the rain caps listed in Table 1.
❑e rain cap exhaust opening must be at least 2 feet (0.6 m)
above the highest roof point within 10 feet, as shown in
Figure 1. See the National Fuel Gas Code, ANSI/NFPA 54
for details on pitched roof applications.
❑See Figure 2 for additional minimum clearances.
Combustion air openings
❑Combustion air must be supplied from the boiler room as
shown in Figure 1. Make sure the installation provides air
openings as required by applicable codes and the Boiler
manual.
Multiple boiler installations
❑Install multiple vents through the roof following all guide-
lines for single-vent installations.
❑Install the vents so they are no closer than 12 inches on
centers.
KN-2 KN-4
Vent components Heat-Fab Heat-Fab
Vent piping/components
(incl. supports, thimbles, etc.)
EZ-Seal
3-inch
EZ-Seal
4-inch
Rain cap vent termination 5300CI 5400CI
Joint sealant, required GE RTV106 or equivalent GE RTV106 or equivalent
