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Bare Heater Model Number
Heater Sales Package PNO
Includes:
Bare Heater
Carton and packing materials
Installation sheet
Single Point Boxes and Supplementary Fuses — When
the unit MOCP device value exceeds 60A, unit−mounted
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. 39.
Single
Point Box
Field Power
Connections
Hinged
Cover
Fig. 39 − Typical Single Point Installation
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.)
On 07 − 14 size units, 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
Table 10 – Heater Model Number
C
R
H
E
A
C
R
H
E
A
A L LI ED P A
C O R P .
MO
D E L N O.
O D
E RI A L N O.
22 .2
ISTED
AIR
UIP
NDITIONING
ACCESS
2 3
1
346N.
3
P / N 2 − 5610
− 4 REV
C11490
T
E
R
0
T
E
R
1
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. 40. 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. 37
and Fig 40.
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. 39. 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.
A L LI E DPA
C O R P .
M O D E LN O.
O D
E R IA L N O.
2 2.2
ISTED
AIR
NDITIONING
1
UIP
ACCESS
2 3
346N.
3
P / N 2 − 5610
− 4 REV
Fig. 40 − Typical Location of Heater Limit Switches
(3−phase heater shown)
Low−Voltage
Control
low−voltage control leads from the heater module(s). The
50TCQ units use a various number of control wires, colors
and terminal boards depending on voltage and unit size.
29
0
1
A
0
0
0
1
A
0
PILOT-CIRCUIT/MANUAL
RESET LIMIT SWITCH
LINE-BREAK
LIMIT SWITCHES
C11489
Connections
—
Pull
0
the
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