Carrier 48KHA - Manual (Page 7)

A CAUTION
Feiilure to follow these precautions could result in dam­
age to unit being installed.
1. Make all electrical connections in accordance with
National Electrical Code ANSI/NFPA 70-1984 and
local electrical codes governing such wiring.
2. Use only copper conductor for connections between the
field-supplied electrical disconnect switch and the unit.
Do not use aluminum or copper-clad aluminum wire.
3. Ensure that high-voltage power to unit is within oper­
ating voltage range indicated on unit rating plate. On
3-phase units, ensure that phases are balanced within
2%. Consult local power company for correction of
improper voltage and/or phase balance.
4. When low-voltage control wires are run in same conduit
as high-voltage wires, insulate low-voltage wires for
highest voltage contained within conduit.
5. Do not damage internal components when drilling
through any panel to mount electrical hardware, con­
duit, etc.
HIGH-VOLTAGE CONNECTIONS-Unit must have a
sepeirate electriceil service with a field-supplied, waterproof,
fused disconnect switch per NEC mounted near, and within
sight from, the unit. Refer to unit rating plate for maximum
fuse size and minimum circuit amps (ampacity) for wire siz­
ing. Table 3 shows recommended wire sizes and lengths
based on rating plate data.
The field-supplied disconnect switch box may be mounted
on unit over the high-voltage inlet hole in control corner
pemel. See Fig. 4.
A WARNING
Label Part No. A74191B, which is shipped loose in bag
of parts, must be affixed to the disconnect switch box.
This label states: "DO NOT DISCONNECT THE
ELECTRICAL POWER TO THIS APPLIANCE
WITHOUT FIRST TURNING OFF THE GAS
SUPPLY.”
Proceed as follows to complete the high-voltage connections
to unit:
1. Connect ground lead to chassis ground connection
when using a separate ground wire.
2. Run high-voltage leads into unit control box and con­
nect to contactor. See unit wiring label and Fig. 6
and 8.
NOTE; On 3-phase units, connect third high-voltage lead to
brown high-voltage pigtail lead. See unit wiring label and
Fig. 8.
SPECIAL PROCEDURES FOR 208-V OPERATION
A WARNING
Make sure power supply to unit is switched OFF before
making any wiring changes. Electrical power may cause
personal injury or death.
For operation on 208 volts, disconnect orange transformer­
primary lead from contactor. See unit wiring label and
Fig. 6. Remove tape emd cover from terminal on end of red
transformer-primary lead. Save cover. Connect red lead to
contactor terminal from which orange lead was dis­
connected.
Using cover removed from red lead, insulate loose terminal
on orange lead. Wrap cover with electricEd tape so that
metal terminal cannot be seen.
NOTE: For some 48KHA,KLA units, the factory-wired
blower-motor speed connections may require changing for
208-v operation to ensure adequate airflow at the rated
external static pressure. See unit wiring label. Insulate all
unused motor leads following same procedures described for
tremsformer leads.
LOW-VOLTAGE CONNECTIONS-Use a suitable room
thermostat as specified on unit wiring label.
Locate room thermostat on an inside wall in space to be con­
ditioned where it will not be subjected to either a cooling or
heating source, or direct exposure to sunlight. Mount ther­
mostat 4 to 5 ft above floor.
Use no. 18 AWG color-coded, insulated (35 C minimum)
v/ires to make low-voltage connections between thermostat
and unit. If thermostat is located more than 100 ft from
unit (as measured along the low-voltage wires), use no. 16
AWG color-coded, insulated (35 C minimum) wires.
A grommeted, low-voltage inlet hole is located in the panel
adjacent to control access panel. See Fig. 4. Run low-voltage
leads from thermostat, through inlet hole and to low-voltage
flagged pigtail leads that run through a hole in bottom of
unit control box. See Fig. 6. Connect thermostat leads to
pigtail leads as shown in Fig. 8
HEAT ANTICIPATOR SETTING—Room thermostat heat
anticipator must be properly adjusted to ensure proper
heating performance. Set heat anticipator, using ammeter
to determine exact required setting.
NOTE: For thermostat selection purposes, use 1.0 amps for
approximate required setting.
Failure to make a proper heat anticipator adjustment will
result in improper operation, discomfort to occupants of
conditioned space and inefficient energy use; however,
required setting may be changed slightly to provide a
greater degree of comfort for a particular installation.