Carrier 50KC04-06 - Single Point Boxes and Supplementary Fuses

26
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 regard-
ing approved heaters.
Unit heaters are marked with heater model numbers. But heat-
ers are ordered as and shipped in cartons marked with a corre-
sponding heater sales package part number. See Table 4 for
correlation between heater model number and sales package
part number.
NOTE: The value in position 9 of the part number differs between
the sales package part number (value is 1) and a bare heater model
number (value is 0).
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-mount-
ed supplementary fuses are required for each heater circuit.
These fuses are included in accessory single point boxes, with
power distribution and fuse blocks. The single point box will
be installed directly under the unit control box, just to the left
of the partition separating the indoor section (with electric
heaters) from the outdoor section. The single point box has a
hinged access cover. See Fig. 37.
Fig. 37 — Typical Single Point Installation
On 50KC units, all fuses are 60-A. Single point boxes contain-
ing fuses for 208/230-v applications use UL Class RK5 250-v
fuses (Bussman FRNR 60 or Shawmut TR 60R). Single point
boxes for 460-v and 575-v applications use UL Class T 600-V
fuses (Bussman JJS 60 or Shawmut A6T 60). (Note that all
heaters are qualified for use with a 60-A fuse, regardless of ac-
tual heater ampacity, so only 60-A fuses are necessary.)
Unit heater applications not requiring supplemental fuses re-
quire a special single point box without any fuses. Connect
power supply conductors to heater conductors and field-sup-
plied base unit power tap leads (see text below regarding
“Completing Heater Installation”) inside the empty single
point box using UL-approved connectors.
SAFETY DEVICES
Electric heater applications use a combination of line-break/
auto-reset limit switches and a pilot-circuit/manual reset limit
switch to protect the unit against over-temperature situations.
Line-break/auto-reset limit switches are mounted on the base
plate of each heater module. See Fig. 38. These are accessed
through the indoor access panel. Remove the switch by remov-
ing two screws into the base plate and extracting the existing
switch.
Pilot-circuit/manual reset limit switch is located in the side
plate of the indoor (supply) fan housing. See Fig. 35.
Table 4 — Heater Model Number
Bare heater
model number
CRHEATER
001A00
Heater Sale Package PNO
Includes:
Bare Heater
Carton and packing materials
Installation sheet
CRHEATER
101A00
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
AL
L
I
E
D
P
A
M
O
DE
L
NO
.
E
R
I
A
L
N
O.
C
O
RP
.
O
D
2
2
.
2
3
1
2
3
ISTED
AIR
NDITIONING
UIP
ACCESS
346
N
.
P
/
N
2-
56
1
0-
4
RE
V
1
1
13
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