SYSTEM OPERATION
13
9.3.8.5
Ducts shall not be screened where terminating in an attic space.
9.3.8.6
Horizontal upper combustion air ducts shall not slope downward
toward the source of combustion air.
9.3.8.7
The remaining space surrounding a chimney liner, gas vent, special
gas vent, or plastic piping installed within a masonry, metal, or factory built
chimney shall not be used to supply combustion air.
Exception: Direct vent appliances designed for installation in a solid fu-
el-burning fireplace where installed in accordance with the manufacture’s
installation instructions.
9.3.8.8
Combustion air intake openings located on the exterior of the
building shall have the lowest side of the combustion air intake openings
located at least 12 in. (300 mm) vertically from the adjoining grade level.
Horizontal Applications and Considerations
Horizontal applications, in particular, may dictate many of
the installation’s specifics such as airflow direction, ductwork
connections, flue and/or combustion air pipe connections, etc.
The basic application of this furnace as a horizontal furnace
differs only slightly from an upright installation. When installing
a furnace horizontally, additional consideration must be given
to the following:
D
rain Trap and Lines
In horizontal applications the condensate drain trap is secured
to the furnace side panel, suspending it below the furnace.
A minimum clearance of 5.5” below the furnace must be
provided for the drain trap. Additionally, the appropriate
downward piping slope must be maintained from the drain
trap to the drain location. Refer to
Condensate Drain Trap and
Lines
section in this manual or the installation instructions for
further details. If the drain trap and drain line will be exposed
to temperatures near or below freezing, adequate measures
must be taken to prevent condensate from freezing.
NOTE:
The use of insulation and/or heat tape is recommended.
Failure to provide proper condensate drainage can result in
property damage.
L
eveling
Leveling ensures proper condensate drainage from the heat
exchanger and induced draft blower. For proper flue pipe
drainage, the furnace must be level lengthwise from end to
end. The furnace should also be level from back to front or
have a slight tilt with the access doors downhill (approximately
3/4”) from the back panel. The slight tilt allows the heat
exchanger condensate, generated in the recuperator coil, to
flow forward to the recuperator coil front cover.
In horizontal installations with the furnace laying on the left
hand side, the alternate vent connection may be used. In this
configuration the internal elbow is removed. The standard
piping connections may also be used in these positions. Refer
to
Vent/Flue Pipe and Combustion Air Pipe
section in the
installation instructions for details concerning the conversion
to the alternate vent/flue and combustion air con
nections on
the 90% furnace.
The 34.5” single stage furnace is one of the products in
our newly redesigned line of shorter chassis furnaces. It is
available in 92% / 96% AFUE up flow / horizontal model and
a down flow / horizontal model.
The up flow / horizontal 34.5” single stage furnace is available
in the following models:
*MES920403ANAA
*MES920603BNAA
*MES9S0803BNAA
*MES920804CNAA
*MES920805CNAA
*MES921004CNAA
*MES921005CNAA
*MES921205DNAA
*MES960403ANAA
*MES960603BNAA
*MES960803BNAA
*MES960804CNAA
*MES960805CNAA
*MES961005CNAA
*MES961205DNAA
The down flow / horizontal 34.5” single stage furnace is
available in the following models.
*CES960403BNAA
*CES960603BNAA
*CES960804CNAA
*CES961005CNAA
*CES961205CNAA
