Configuring Units For Downflow (Vertical) Discharge; Install Electrical Connections - Carrier 50GL030 Installation, Start-Up, And Operating Instructions Manual

CONFIGURING UNITS FOR DOWNFLOW (VERTICAL) DIS-
CHARGE
Before performing service or maintenance operations on the
system, turn off main power to unit or electrical shock could
result.
1. Open all electrical disconnects before starting any service
work.
2. Remove side duct covers to access bottom return and supply
knock out covers (See Fig. 10).
3. To remove supply and return duct covers, break front and right
side connecting tabs with a screwdriver and a hammer. Push
cover down to break rear and left side tabs.
4. If unit ductwork is to be attached to vertical opening flanges
on the unit basepan (jackstand applications only), do so at this
time. Collect ALL screws that were removed. Do not leave
screws on rooftop as permanent damage to the roof may occur.
5. It is recommended that the basepan insulation around the
perimeter of the vertical return-air opening be secured to the
basepan with aluminum tape. Applicable local codes may
require aluminum tape to prevent exposed fiberglass.
6. Cover both horizontal duct openings with the duct covers
shipped on the unit from the factory. Ensure opening is air-and
watertight.
7. After completing unit conversion, perform all safety checks
and power up unit.
NOTE: The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence-type air conditioning and ventilating systems, NFPA
90A or residence-type, NFPA 90B; and/or local codes and
ordinances.
Adhere to the following criteria when selecting, sizing, and
installing the duct system:
8. Select and size ductwork, supply-air registers, and return-air
grilles according to American Society of Heating, Refrigera-
tion and Air Conditioning Engineers (ASHRAE) recommen-
dations.
9. Use flexible transition between rigid ductwork and unit to
prevent transmission of vibration. The transition may be
screwed or bolted to duct flanges. Use suitable gaskets to
ensure weathertight and airtight seal.
10. All units must have field-supplied filters or accessory filter
rack installed in the return-air side of the unit. Recommended
sizes for filters are shown in Table 1.
11. Size all ductwork for maximum required airflow (either
heating or cooling) for unit being installed. Avoid abrupt duct
size increases or decreases or performance may be affected.
12. Adequately insulate and weatherproof all ductwork located
outdoors. Insulate ducts passing through unconditioned space,
and use vapor barrier in accordance with latest issue of Sheet
Metal and Air Conditioning Contractors National Association
(SMACNA) and Air Conditioning Contractors of America
(ACCA) minimum installation standards for heating and air
conditioning systems. Secure all ducts to building structure.
13. Flash, weatherproof, and vibration-isolate all openings in
building structure in accordance with local codes and good
building practices.
SUPPLY
DUCT
OPENING
Fig. 9—Supply and Return Duct Opening
Step 8—Install Electrical Connections
The unit cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of personal
injury if an electrical fault should occur. This ground may
consist of an electrical wire connected to the unit ground lug
in the control compartment, or conduit approved for electrical
ground when installed in accordance with NEC (National
Electrical Code) ANSI/ NFPA (latest edition) (in Canada,
Canadian Electrical Code CSA [Canadian Standards Associa-
tion] C22.1) and local electrical codes. Failure to adhere to
this warning could result in personal injury or death.
7
RETURN
DUCT
OPENING
C99011