Installation: Mechanical
GMND-SVX01B-EN
13
Increasing the clearance distances may be necessary if
there is a possibility of distortion or discoloration of
adjacent materials.
Accessibility
The Separated Combustion Duct Furnace is a bottom
service access type. Allow a minimum of 25 inches
(635 mm) at the bottom of the unit to facilitate servicing
the burners and pilot. Provision should also be made to
assure accessibility for recurrent maintenance purposes.
Atmospheres containing commercial solvents or
chlorinated hydrocarbons will produce corrosive acids
when coming in contact with the flames. This will greatly
reduce the life of the gas duct furnace and may void the
warranty. Avoid such areas.
The Separated Combustion Duct Furnace must be
installed on the positive pressure side of the air circulation
blower.
Ductwork
Properly designed and installed ductwork, providing a
uniformly distributed flow of air across the surfaces of the
heat exchanger, is essential to satisfactory unit
performance and life of the equipment.
All duct connection flanges/seams must be sealed to
prevent air leaks. Sealant/tape must be suitable for
temperatures 250°F (121°C) minimum.
If uniform air distribution is not obtained, install additional
baffles and/or turning vanes in the ductwork.
Figure 5
and
Figure 6
illustrate recommended ductwork
designs for both the straight-through and elbowed air inlet
arrangements.
Access panels large enough to observe smoke and
reflected light, and to detect the presence of leaks in the
heating equipment, are required both upstream and
downstream from gas duct furnaces. These panels must
be sealed to prevent air leaks. If allowed by local
regulations, install canvas connectors between the
ductwork and fan discharge opening to eliminate the
transmission of sound.
Air Flow
The installation is to be adjusted to obtain an air
throughput within the range specified on the appliance
rating plate.
Bypass
When a gas duct furnace is installed to operate in
conjunction with a summer air conditioning system, the
cfm air delivery of the system blower should be adjusted
to meet the design air volume requirements for cooling. If
this cfm delivery is greater than that required for heating,
resulting in a low air temperature rise, install a damper
WARNING
Fire Hazard!
If the gas duct furnace is to be used in a building
classified as having a hazardous atmosphere, the
installation must comply with the standards set by the
National Board of Fire Underwriters. Consult the
authorities having jurisdiction before starting the job.
Failure to follow recommendations could result in
death or serious injury.
NOTICE:
Use 90° Duct Connection Flanges!
Ducts must be properly connected to duct furnaces for
operation. Do not straighten the 90° duct connection
flanges on the duct furnaces. Straightening the 90° duct
connection flanges will affect the operation of the
furnace and will void the warranty.
Figure 5.
Recommended design for field installation of
ductwork for straight-through arrangement
Figure 6.
Recommended ductwork design for elbowed
arrangement
