Carrier 50TCQD17-D24 Service And Maintenance Instructions page 25

On 50TCQ units, all fuses are 60- - A. Single point boxes
containing 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 actual
heater ampacity, so only 60- - A fuses are necessary.)
LCTB
CONTL
BOARD
2
VIO
3
ORN
12
BRN
ORN
1
TB4
VIO
Field
Connections
HR1: On Heater 1 in Position #1
HR2: On Heater 2 in Position #2 (if installed)
Fig. 36 - - Accessory Electric Heater Control
Connections
On 50TCQ units, all fuses are 60A. Single point boxes
containing fuses for 208/230V applications use UL Class
RK5 250V fuses (Bussmann FRNR 60 or Shawmut TR
60R). Single point boxes for 460V and 575V applications
use UL Class T 600V fuses (Bussmann JJS 60 or
Shawmut A6T 60). (Note that all heaters are qualified for
use with a 60A fuse, regardless of actual heater ampacity,
so only 60A fuses are necessary.)
Unit heater applications not requiring supplemental fuses
require a special Single Point Box without any fuses.
Connect power supply conductors to heater conductors
and field- - supplied base unit power tap leads (see text
below re: "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. 34. These are
accessed through the indoor access panel. Remove the
switch by removing 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. 34.
BRN
VIO
2 3
VIO
BRN BRN
Elec Htr
VIO BRN
HR2
VIO
HR1 BRN
C08331
Fuse
Holder
Terminal
Block
Fig. 37 - - Typical Single Point Installation
18 GA.
RED (HI-TEMP)
FEED WIRES THRU
STRAIN RELIEF BUSHING
IN CONTROL PANEL
Fig. 38 - - Typical Location of Heater Limit Switches
(3- - phase heater shown)
Completing Heater Installation
Field Power Connections — Tap conductors must be
installed between the base unit's field power connection
lugs and the Single Point Box (with or without fuses). See
Fig. 32. Refer to unit wiring schematic. Use copper wire
only. For connection using the single point box without
fuses, connect the field power supply conductors to the
heater power leads and the field- - supplied tap conductors
inside the Single Point Box. Use UL approved pressure
connectors (field- - supplied) for these splice joints.
25
INSULATED
TERMINALS
AT LIMITS
BLACK
12 GA.
RED (HI-TEMP)
BLACK
12 GA.
12 GA.
12 GA.
BLACK
12 GA.
YELLOW
BLUE
12 GA.
BLACK 12 GA.
12 GA.
YELLOW
BLUE
C09424
HTR 2
HTR 1
C10761