Service manual

SC Series Boilers – Installation and Service Manual
10
Figure 2. Side Termination Installation
Vent Installation
The boiler must be vented to the outdoors. Do not install the vent into a common venting system and do
not install a vent damper, or similar device to the venting system or the boiler. Vent connectors serving
the boiler must not be connected into any portion of
mechanical draft systems operating under positive
pressure. The venting can be installed as a direct
vent system in which the air for combustion is
obtained from the outdoor atmosphere directly or as
a non-direct vent in which all air for combustion is
obtained from the boiler room. The vent system will
have a positive pressure in the flue requiring that all
vent joints and seams be sealed gas-tight by
following the vent manufacturer’s instructions.
Follow the vent manufacturer’s instructions for
installation of the venting system, and firestop
spacers, thimbles, caps, roof flashing, storm collar,
supports, etc. The vent connector and firestop must
provide correct spacing to combustible surfaces, as
specified in the section 2.3. Venting is approved for combustible wall passage with a clearance of 2.5"
from the flue pipe in any direction.
Since the vent system will operate with a positive pressure in the exhaust vent pipe, it is critical that all
joints be properly cleaned and thoroughly sealed as per the vent manufacturer’s instructions. The
exhaust may condensate in the vent with a longer vent length installation. The condensate of exhaust is
acidic and can cause severe corrosion of ordinary venting materials. Boiler operation can be affected by
restrictive vent and combustion air supply piping. Therefore, the venting system must completely
conform to the requirements of Table 1. The specified minimum and maximum equivalent vent length
listed for each boiler model must be followed.
For a sidewall venting installation with one horizontal run and a short vertical section as shown in Figures
3, 4 and 5, the exhaust venting run must slope downward at least ¼ inch per foot from the beginning of
horizontal run to the vent termination. There should be no sagging of the vent. This is to ensure that any
condensate in the horizontal venting flows outside through the opening of the termination.
All horizontal runs for a vertical venting installation, as shown in Figures 6, 7 and 8, shall slope upward
not less than ¼ inch per foot. This is to ensure that any condensate in the venting flows back towards
the boiler so that the condensate can be disposed of through the condensate disposal system installed on
the venting horizontal section closest to the boiler. A condensation drain should be obtained from the
supplier of the venting system.
The venting shall be supported as required by applicable code(s) so that its weight does not bear on the
boiler. All vent pipes must be adequately supported with vent supports no less than five feet apart or as
per the vent system manufacturer’s instruction, and at smaller intervals if necessary to ensure that there
are no sagging sections along the horizontal runs. Noncombustible pipe strap or hangers suitable for the
weight can be used to support horizontal runs and maintain vent location.
Provide minimum 2.5 inches clearance from vent components to combustible materials. Use a wall
thimble when penetrating a combustible wall.
Example venting configurations are shown in Figures 3 – 8. (Follow supplier’s venting installation
instructions for all installations shown)