Horizontal Venting; Flexible Vent Systems - Heat Controller 80+ AFUE Installation Instructions Manual

codes. The minimum diameter of any vent pipe is 4
inches.
• The venting system should be designed to have the
minimum number of elbows or turns. All horizontal runs
shall slope upwards from the furnace at ¼ inch per
running foot of vent. Supports for the vent pipe must
be installed a minimum of every five feet along the vent
run to ensure no displacement after installation. Under
no circumstances shall any portion of the vent system
extend into or pass through any return air duct, supply
air duct, or plenum.
• Single wall vent connectors may be used under the
limited capacity ranges found in the vent sizing tables.
It is recommended that Type B double wall vent be
used for the connector whenever possible. An existing
masonry chimney should be inspected and relined if
necessary.
• Single wall metal vertical vents shall not be used for
Category I venting. The furnace vent, if metal, may
be insulated if local codes allow. Any part of the vent
system, metal vent only, not exposed to weather,
but which are exposed to temperatures below 35° F
(1° C) must be insulated to prevent condensation. All
vent insulation shall be foil backed fiberglass of one
inch minimum thickness.
• Sheet metal fasteners should be used to secure the vent
pipe to the furnace flue. However, the NFGC states that
alternative vent products may be attached according to
the vent manufacturers instructions.
• When an existing furnace is removed from a vent
system serving other appliances, the existing vent
system may no longer be sized to properly vent the
remaining appliances. An improperly sized venting
system can result in the formation of condensate,
leakage, or spillage. The existing vent system should
also be checked to make sure it remains in compliance
with NFGC. If it isn't, the vent system must be brought
into compliance before installing the furnace.
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Horizontal Venting

• Horizontal vent systems must be sealed with a high
temperature sealant that can withstand temperatures of
450° F. Recommended sealants: Dow Corning Sealant
736 RTV; GE 106 RTV; High Tech Ind., High TEMP
RED.
• This furnace is not approved for horizontal venting
without the use of an add-on power venter. Power
venters establish negative pressure in the vent piping
and the furnace operates as if connected to a Category
I vertical vent. The power venter is only for use when
exhausting through an exterior wall.
• The power venter must be installed according to the
instructions provided by the power venter manufacturer
and applicable requirements of local codes. For
Canadian installations please refer to the Canadian
Installation Code (CAN/CGA-B149.1 or 2) and/or local
codes.
• The outlet of the vent must be at least 12 inches above
the highest expected snow accumulation.

Flexible Vent Systems

Flexible venting systems are approved for use providing
they are listed for the application and meet all local Code
requirements. These systems are primarily used to line
existing masonry chimneys. They must be sized to the
application according to the sizing tables in the National
Fuel Gas Code, including the required 20% reduction in
maximum capacity.
Flexible venting systems are permitted to be used as the
vent connector. However, great care must be taken to
ensure that there are no sags in the venting system which
could accumulate condensate. The flexible vent system
must be supported at no more than 5 foot intervals and
maintain a minimum slope of ¼ inch per foot of horizontal
run.