Carrier 50NQ - Manual (Page 6)

drain tube downward at a slope of at least 1 in, in every 10
ft of horizontal run. Be sure to check the dreun 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 instaJlations. When using a gravel
apron, make sure it slopes away from the unit.
Step 3—Duct Connections
Model 50NQ has duct flemges on the supply and return mr
openings on the side and bottom of the unit except on sizes
048 and 060. 048 and 060 sizes do not have flanges on side
dischetrge openings. See Figs. 2 and 3 for connection sizes
and locations.
NOTE; The design and insteJlation of the duct system must
be in accordance with the standards of the National Fire
Protection Association for installation of nonresidence-type
air conditioning and ventilating systems, NFPA No. 90A or
residence type, NFPA No. 90B, and/or loced codes and
ordinances.
Adhere to the following criteria when selecting, sizing, and
installing the duct system:
1. Remove appropriate panels from unit to obtain either
horizontal or down discharge. If models 018 through
042 are installed in horizontal discharge applications,
remove side duct covers, save screws, and instedl the
covers on bottom duct openings. To install duct covers
on bottom duct openings, remove one flange which
interferes with heater mounting plate. For models 048
through 060 remove either side or bottom duct covers
as needed and discard.
2. Select and size ductwork, supply-air registers, and
return-air grilles according to ASHRAE recom­
mendations. Refer to Tables 2 & 3 for static pressure
capability.
A CAUTION
When the duct-system fastening holes are being drilled
into side of unit instead of the unit duct flanges, use
extreme care to avoid puncturing the coil or coil tubes.
See Fig. 9.
5.
6 .
3. Use flexible transition between rigid ductwork and unit
to prevent transmission of vibration. The transition
may be screwed or bolted to duct flemges. Use suitable
gaskets to ensure weather and edrtight seed.
«
4. Install external, field-supplied air filter(s) in return-air*
ductwork where it is easily accessible for service. Rec­
ommended filter sizes are shown in Table 4.
Size all ductwork for maximum required airflow (either
heating or cooling) for unit being installed. Avoid
abrupt duct size increases or decreases.
Adequately insulate and weatherproof all ductwork
located outdoors. Insulate ducts passing through
unconditioned space and use vapor barrier in accor­
dance with latest issue of SMACNA and ACCA mini­
mum installation standards for heating and air condi­
tioning systems. Secure edl ducts to building structure.
Flash, weatherproof, and vibration-isolate £dl openings
in building structure in accordance with local codes and
good building practices.
For
Canadian Installations Only—An L-shaped
exhaust duct fabricated of sheet metal or a material
rated 94-5V shall be used in the case of downflow
applications.
7.
8.
Step 4—Electricial Connections
A WARNING
The unit cabinet must have an uninterrupted, unbro­
ken, electrical ground to minimize the possibility of per­
sonal injury if an electriced fault should occur. This
ground may consist of electrical wire connected to the
unit ground lug in the control compartment, or conduit
approved for electriced ground when instedled in accor­
dance with the National Electrical Code ANSI/NFPA-
70 (in Canada, Canadian Electrical Code CSA C22.1)
and loced electriceil codes.
A CAUTION
A failure to follow these precautions could result in
damage to the unit being installed:
1. Meike all electrical connections in accordance with the
latest National Electrical Code, ANSI/NFPA-70 and
local electrical codes governing such wiring. In Canada,
all electrical connections must be in accordance with
CSA standead C22.1 Canadian Electrical Code part 1
and applicable local codes. Refer to Unit Wiring
Diagram.
2. Use only copper conductor for connections between
field-supplied electrical disconnect switch and unit. DO
NOT USE ALUMINUM WIRE.
3. Ensure that high-voltage power to unit is within oper­
ating voltage range indicated on unit rating plate (Fig.
4). On 3-phase units, ensure that phases are voltage
and current balanced. Consult local power company for
correction of improper voltage and/or phase balance.
4. Insulate low-voltage wires for highest voltage con­
tained within conduit when low-voltage control wires
are run in same conduit as high-voltage wires.
5. Do not damage internal components when drilling
through any panel to mount electriceil hardware, con­
duit, etc.
CAUTION: DO NOT DRILL
OR SCREW IN SHADED AREA 5 0"-
O
SUPPLY RETURN
INLET/OUTLET PANEL
Cabinet Size A
Smaii Cabinet 20-1/2"
018-042
Large Cabinet 21-1/4"
048-060
Fig. 9—Location of Coii Area-
Not to be Drilied