7
Roof Curb Installation
RIGGING DETAILS
WARNING
To prevent property damage, the unit should remain in an
upright position during all rigging and moving operations. To
facilitate lifting and moving when a crane is used, place the
unit in an adequate cable sling.
IMPORTANT NOTE:
If using bottom discharge with roof
curb, ductwork should be attached to the curb prior to install-
ing the unit. Ductwork dimensions are shown in roof curb
installation instructions.
Refer to the Roof Curb Installation Instructions for proper
curb installation. Curbing must be installed in compliance
with the National Roofing Contractors Association Manual.
Lower unit carefully onto roof mounting curb. While rigging
unit, center of gravity will cause condenser end to be lower
than supply air end.
Rigging
GAS PIPING
IMPORTANT NOTE
: This unit is factory set to operate on natural
gas at the altitudes shown on the rating plate.
WARNING
To prevent property damage, personal injury or death when
using propane gas alone or at higher altitudes, obtain and
install the proper conversion kit(s). Failure to do so can
result in unsatisfactory operation and/or equipment damage.
High altitude kits are for the U.S. Installations only and are
not approved for the use in Canada.
The rating plate is stamped with the model number, type of
gas and gas input rating. Make sure the unit is equipped to
operate on the type of gas available. Conversion to LP gas is
permitted with the use of a factory authorized conversion kit.
Contact your distributor or refer to the specification sheet for
your model for a listing of approved LP gas conversion kit(s).
Refer to the Installation Manual provided with the LP kit for
conversion from natural gas to propane gas.
Natural
Min. 5.0" W.C., Max. 10.0" W.C.
Propane
Min. 11.0" W.C., Max. 13.0" W.C.
INLET GAS PRESSURE
Inlet Gas Pressure Must Be Within the Minimum and Maxi-
mum Value Shown in Table Above.
The minimum supply pressure should not vary from that
shown in the Inlet Gas Pressure table because this could
prevent the unit from having dependable ignition. In addition,
gas input to the burners must not exceed the rated input
shown on the rating plate. Overfiring of the unit could result
in premature heat exchanger failure.
High Altitude Derate (U.S. Installations Only)
Installation of this furnace at altitudes above 2000 ft (610 m)
shall be made in accordance with the Listed High Altitude
Conversion Kit available with this furnace.
D’installation de ce générateur de chaleur à des altitudes
supérieures à 2000 pi (610 m) doit être effectuée conformé
-
ment aux instructions accompagnant la trousse de conver-
sion pour haute altitude fournie avec cet appareil.
IMPORTANT NOTE:
The gas/electric units naturally derate
with altitude. Do not attempt to increase the fir ing rate by
changing orifices or increasing the manifold pressure. This
can cause poor combustion and equipment failure. At all alti-
tudes, the manifold pressure must be within 0.3 inches W.C.
of that listed on the nameplate for the fuel used. At all alti-
tudes and with either fuel, the air tempera ture rise must be
within the range listed on the unit nameplate. Contact your
distributor or refer to the specification sheet for your model
for listing of approved high altitude conversion kit(s). Refer
to the Installation Manual provided with the high altitude kit
for altitude adjustments.
NOTE:
No changes are required up to 2,000 feet. Use the
appropriate high altitude kit above 2,000 feet.
