Carrier 48N - Manual (Page 4)

This publication contains the following:
Step 1. Moving and Setting Unit in Place
Condensate Disposal
Venting
Gas Piping
Duct Connections
Electrical Connections
7. Preparing Unit for Steurtup
8. Heating Section Startup and Adjustments
9. Cooling Section Startup and Adjustments
Care and Maintenance
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Step 10.
Step 1—Moving and Setting Unit in Place
A CAUTION
Use spreader bars and crate top when rigging the unit
to be lifted. Model 48N must be rigged for lifting as
shown in Fig. 4. Use extreme caution to prevent dam­
age when moving the unit. Unit must remain in an
upright position during eJl rigging and moving opera­
tions. The unit must be level for proper condensate
drainage; therefore, the ground-level pad or accessory
roof-mounting curb must be level before setting the
unit in place. When a field-fabricated support is used,
ensure that the support is level and properly supports
the unit.
A. Rooftop installation
A CAUTION
When installing the unit on a rooftop, be sure that the
roof will support the additional weight. Refer to Figs. 2
& 3 for Model 48N to obtain toted weight and corner
weight information.
For downflow applications, an accessory roof-mounting
curb must be installed on, and flashed into the roof before
unit installation. The instructions for installing the acces­
sory curb are packaged with the curb.
For end-discharge applications place the unit on a level base
that provides proper support. On flat roofs, be sure that the
unit is located at least 4-ins. above the highest expected
water level on the roof to prevent flooding.
B. Ground-Level Installation
Place the unit on a sohd, level, concrete pad that is a mini­
mum of 2-ins. thick and that extends approximately 2-in.
beyond the casing on all four sides of the unit. Do not secure
the unit to the pad except when required by local codes.
C. Clearances
The required minimiim operating and service clearances are
shown in Figs. 2 and 3. Adequate combustion, ventilation
and condenser air must be provided.
A CAUTION
Do not restrict condenser airflow. An air restriction at
either the outdoor-air inlet (the entire surface of the out­
door cofl.) or the fan discharge can be detrimental to
compressor hfe.
The condenser fan discharges through the top of the unit.
Ensure that the fan discheirge does not recirculate to the
condenser coil. Do not locate the unit in either a corner or
under a complete overhead obstruction. The minimum clear­
ance under a partial overhang (such as a normal house roof
overhang) is 48-ins. above unit top. The maximum horizon­
tal extension of a partial overhang must not exceed 48-in..
Do not locate the unit where water, ice, or snow from an
overhang or roof wiU damage or flood the unit by falling on
the top. Do not locate the unit where grass, shrubs, or other
plants will interfere with the airflow either into or out of the
unit. Do not install the unit on carpeting, tile, or other com­
bustible material other than wood flooring. Furnace may be
installed on wood flooriag or on Class A, B, or C roof cover­
ing materials.
Step 2—Condensate Disposal
NOTE: Ensure that condensate-water disposal methods
comply with local codes, restrictions, and practices.
Model 48N disposes of condensate water through a 3/4-in.,
Male Female NPT drain fitting. See Figs. 2 and 3 for
location.
Install a 2-in. trap at the drain fitting to ensure proper
drainage. See Fig. 5. Make sure that the outlet of the trap is
at least 1-in. lower than the unit drain pan connection to
prevent the pan from overflowing. Prime the trap with
water.
If the installation requires draining the condensate water
away from the unit, connect a drain tube using a minimum
of 7/8-in. OD copper tubing, 3/4-in. galvanized pipe, or
3/4-in. plastic pipe. Do not undersize the tube. Pitch the
drain tube downward at a slope of at least 1-in. in every 10-
ft of horizontal run. Be sure to check the drain tube for
leaks.
Condensate water can be drained directly onto the roof in
rooftop installations (where permitted) or onto a gravel
apron in ground-level installations. When using a gravel
apron, make sure it slopes away from the unit.
Step 3—Venting
The vent-cap assembly is shipped in the burner compart­
ment. Remove the access door to locate the assembly.