For Units With Accessory Or Optional Elec- Tric Heaters - Carrier WeatherExpert Puron 50LC 08 Series Installation Instructions Manual

Step 5 — Field Fabricate Ductwork
Cabinet return-air static pressure (a negative condition) shall not
exceed 0.35 in. wg (87 Pa) with economizer or 0.45 in. wg
(112 Pa) without economizer.
For vertical ducted applications, secure all ducts to roof curb and
building structure. Do not connect ductwork to unit.
Fabricate supply ductwork so that the cross sectional dimensions
are equal to or greater than the unit supply duct opening dimen-
sions for the first 18-in. (458 mm) of duct length from the unit
basepan.
Insulate and weatherproof all external ductwork, joints, and roof
openings with counter flashing and mastic in accordance with ap-
plicable codes.
Ducts passing through unconditioned spaces must be insulated
and covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return should be
ducted through the roof deck to comply with applicable fire codes.
FOR UNITS WITH ACCESSORY OR OPTIONAL ELEC-
TRIC HEATERS
All installations require a minimum clearance to combustible sur-
faces of 1-in. (25 mm) from duct for first 12-in. (305 mm) away
from unit.
Outlet grilles must not lie directly below unit discharge.
WARNING
PERSONAL INJURY HAZARD
Failure to follow this warning could cause personal injury.
For vertical supply and return units, tools or parts could drop
into ductwork and cause an injury. Install a 90 degree turn in
the return ductwork between the unit and the conditioned
space. If a 90 degree elbow cannot be installed, then a grille of
sufficient strength and density should be installed to prevent
objects from falling into the conditioned space. Due to electric
heater, supply duct will require 90 degree elbow.
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in damage to roofing
materials.
Membrane roofs can be cut by sharp sheet metal edges. Be
careful when placing any sheet metal parts on such roof.
Step 6 — Rig and Place Unit
When the unit is ready to be rigged and no longer will be lifted by
a fork truck, the wood protector under the basepan must be re-
moved. Remove 4 screws from each base rail. Wood protector will
drop to the ground. See instructions on the unit base rails.
Keep unit upright and do not drop. Spreader bars are not required.
Rollers may be used to move unit across a roof. Level by using
unit frame as a reference. See Table 2 and Fig. 7 for additional in-
formation.
Lifting holes are provided in base rails as shown in Fig. 7. Refer to
rigging instructions on unit.
Rigging materials under unit (cardboard or wood) must be re-
moved PRIOR to placing the unit on the roof curb.
When using the standard side drain connection, ensure the red
plug in the alternate bottom connection is tight. Do this before set-
ting the unit in place. The red plug can be tightened with a
square socket drive extension. For further details, see "Install Ex-
ternal Condensate Trap and Line" on page 14.
Before setting the unit onto the curb, recheck gasketing on curb.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
All panels must be in place when rigging. Unit is not designed
for handling by fork truck when packaging is removed.
If using top crate as spreader bar, once unit is set, carefully
lower wooden crate off building roof top to ground. Ensure
that no people or obstructions are below prior to lowering the
crate.
11
CAUTION
CAUTION
/ -in.
1
2