Unit Without Thru-Base Connection Kit; Heat Anticipator Settings; Electric Heaters; Step 12 - Adjust Factory-Installed Options - Carrier 50LCH Series Start-Up Instructions

UNIT WITHOUT THRU-BASE CONNECTION KIT

Pass the control and communication control wires through the
bushing on the unit end panel. Route the wire through the snap-in
wire tie and up to the web bushing near the control box. Route the
wire through the bushing and into the bottom left side of the con-
trol box after removing one of the two knockouts in the corner of
the box. Using a connector at the control box to protect the wire as
it passes into the control box, pull the wires over to the required
connection points in the control box. Use the connector at the con-
trol box and the wire tie to ensure that the control and communi-
cating wire is tight and will not be damaged by contact with the
condenser coil. See Fig. 41.
NOTE: If thru-the-bottom connections accessory is used, refer to
the accessory installation instructions for information on routing
power and control wiring.
NOTE: Using the bushings and wire ties will ensure all low and
high voltage wiring are separated in accordance with UL and NEC
requirements.
Fig. 41 — Thermostat Wire Routing

HEAT ANTICIPATOR SETTINGS

Set heat anticipator settings at 0.14 amp for the first stage and
0.14 amp for second-stage heating, when available.

ELECTRIC HEATERS

50LC*H 07-12 units may be equipped with factory-installed elec-
tric heaters. The heaters are modular in design, with heater frames
holding open coil resistance wires strung through ceramic insula-
tors, line-break limit switches and a control contactor. 1 or 2 heater
modules may be used in a unit.
Heater modules are installed in the compartment below the indoor
(supply) fan outlet. Access is through the indoor access panel.
Heater modules slide into the compartment on tracks along the
bottom of the heater opening. See Fig. 42.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Not all available heater modules and single point boxes may
be used in every unit. Use only those heater modules that are
UL listed for use in a specific size unit. Refer to the label on
the unit cabinet for the list of approved heaters and single point
boxes.
Fig. 42 — Typical Component Location
Step 12 — Adjust Factory-Installed Options

SMOKE DETECTORS

Smoke detectors are available as factory-installed options on all
unit sizes. Smoke detectors may be specified for supply air only,
for return air with or without economizer, or in combination of
supply air and return air. Return-air smoke detectors are ar-
ranged for vertical return configurations only. All components
necessary for operation are factory-provided and mounted. The
unit is factory-configured for 30 second smoke detector shut-
down operation; additional wiring or modifications to the
SmartVu control may be necessary to complete the unit and
smoke detector configuration to meet project requirements.
Units equipped with factory-optional return-air smoke detectors
require a relocation of the sensor module at unit installation. See
Fig. 44 for the as-shipped location.
Completing Installation of Return Air Smoke Sensor
1. Unscrew the two screws holding the return air smoke
detector assembly. See Fig. 45, Step 1. Save the screws.
2. Turn the assembly 90 degrees and then rotate end to end.
Make sure that the elbow fitting is pointing down. See
Fig. 45, Step 2.
3. Screw the sensor and detector plate into its operating posi-
tion using screws from Step 1. See Fig. 45, Step 3.
4. Connect the flexible tube on the sampling inlet to the sam-
pling tube on the basepan.
Additional Application Data
Refer to Factory-Installed Smoke Detectors for Small and Medi-
um Rooftop Units 2 to 25 Tons for instruction and explanation on
additional control features of these smoke detectors including
multiple unit coordination.

DUCT PRESSURE TRANSDUCER

The unit can be equipped with factory wired and installed duct
pressure transducer for variable speed fan operation based on duct
static pressure. See Fig. 43. The 1/4 in. OD (outside dimensions)
high pressure pickup port must be piped to the supply duct for
pressure measurement.
First, identify a location in the supply ductwork for pressure mea-
suring. The sensing location should be 1/3 to 2/3 of the way down
the ductwork, if possible. Make sure the pressure sensing location
is away from any duct accessories that would cause pressure dis-
turbances, such as turning vanes, duct tees or wyes, VAV (Variable
Air Volume) boxes, or smoke dampers. Install a static pressure
probe for best results.
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