Carrier 50KC04, Installation Instructions Manual, Page: 20 / 52

20
Electric Heaters
The 50KC units may be equipped with field-installed accessory
electric heaters. The heaters are modular in design, with heater
frames holding open coil resistance wires strung through ceramic
insulators, line-break limit switches and a control contactor. One
or two 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. 34-36.
Not all available heater modules 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 ap -
proved heaters.
Fig. 34 — Typical Access Panel Location (3-5 Ton)
Fig. 35 — Typical Component Location
Fig. 36 — Typical Module Installation
SINGLE POINT BOXES AND SUPPLEMENTARY FUSES
When the unit MOCP device value exceeds 60-A, unit-mounted
supplementary fuses are required for each heater circuit. These
fuses are included in accessory single point boxes, with power dis -
tribution and fuse blocks. The single point box will be installed di -
rectly under the unit control box, just to the left of the partition
separating the indoor section (with electric heaters) from the out -
door section. The single point box has a hinged access cover. See
Fig. 37. The single point box also includes a set of power taps and
pigtails to complete the wiring between the single point box and
the unit’s main control box terminals. Refer to the accessory heater
and single point box installation instructions for details on tap con -
nections.
All fuses on 50KC units are 60-A. (Note that all heaters are quali -
fied for use with a 60-A fuse, regardless of actual heater ampacity,
so only 60-A fuses are necessary.)
SINGLE POINT BOXES WITHOUT FUSES
Unit heater applications not requiring supplemental fuses require a
special single point box without any fuses. The accessory single
point boxes contain a set of power taps and pigtails to complete
the wiring between the single point box and the unit’s main control
box terminals. Refer to accessory heater and single point box in -
stallation instructions for details on tap connections.
Fig. 37 — Typical Single Point Installation
DISCONNECT MOUNTING
LOCATION
UNIT BLOCK-OFF
PANEL OUTDOOR
ACCESS PANEL
INDOOR
ACCESS
PANEL
DISCONNECT
MOUNTING
LOCATION EMT OR RIGID CONDUIT
(FIELD-SUPPLIED) SINGLE
POINT BOX CENTER
POST
HEATER
COVERS
HEATER
MOUNTING
BRACKET HEATER
MODULE
(LOCATION 2) HEATER
MODULE
(LOCATION 1)
SINGLE POINT
BOX
MOUNTING
SCREW
BRACKET AND
CONDUIT
DRIP BOOT MAIN
CONTROL
BOX
CONTROL WIRE TERMINAL BLOCK
MANUAL RESET
LIMIT SWITCH
TRACK
FLANGE
ALLIED PA
MODEL NO.
ERIAL NO.
CORP.
11 13
21 23
OD
22.2
3
1
23
ISTED AIR
NDITIONING
UIP ACCESS
346N
.
P / N 2-
5610-4 REV
1
1
1
3
2
1
2 3
CONTROL
BOX
BUSHING
SINGLE
POINT BOX
MOUNTING
SCREWS
FOAM
BUSHING
DRIP BOOT
BRACKET
MOUNTING
SCREWS
HEATER
RELAYS
POWER
WIRES
HEATER
MOUNTING
SCREWS