7
Fig. 1 — Typical Single Point Kit Installation
NO FUSES (NON-HIGH SCCR VERSION ONLY)
If the unit’s MOCP device rating is 60-A or less, then the MOCP
device is recognized as providing the required overcurrent
protection to the heater and no internal fusing is required. If two
heater modules are installed, a single point box that contains only
a field power terminal block is required. See tables at the
beginning of Appendix A, B and C for where-used information on
the single point boxes and for the relevant connections wiring
diagram.
For High SCCR option, see Tables A-C (Single Point BoxWiring
Diagrams) of Appendix D on page 76 for information on the
single point boxes and see Fig. AY-BB for the relevant connection
wiring diagram.
UNITS WITH FACTORY-INSTALLED HACR
(NON-HIGH SCCR VERSION ONLY)
NOTE: HACR is not available on the High SCCR option.
The amp rating of the HACR factory-installed option is based on
the size, voltage, indoor motor and other electrical options of the
unit as shipped from the factory. When field-installed accessory
electric heaters are added or changed in the unit, the HACR may
no longer be of the proper amp rating and therefore will need to be
removed from the unit. See unit nameplate and label on factory
installed HACR for the amp rating of the HACR that was shipped
with the unit from the factory. See unit nameplates for the proper
fuse, HACR or maximum over-current protection device required
on the unit with field installed electric heat.
HIGH SCCR OPTION
Unlike the non-High SCCR version, fuses for electric heater cir
-
cuits are required regardless of the unit’s MOCP to provide the
unit rated High SCCR rating for the electric heaters.
Additionally, unlike the non-High SCCR version, TB10’s are not
required for the High SCCR option.
Units with High SCCR ratings must use a single point box
(specifically for High SCCR application) for all electric heat
installations. These boxes contain High SCCR fusing rated to
protect the heaters. General installation of the Single Point Box
(SPB) and Electric Heaters is the same fro both STD SCCR and
High SCCR units. Unit power wiring must enter through the
SPB and then power is routed to the Unit Control Fuse Box
using wire harness provided. See High SCCR Single Point Box
installation details in this document.
Electric Heaters
Heaters are shipped with one heater per carton. The carton is
marked with a Sales Package Number. On all heaters except
CRHEATER101A00 through 119A00, 103B00, 104B00, 113B00
through 116B00, 128B00, and 129B00, the heater Model Number
(as marked on the heater infoplate) is the same as the Sales
Package number. On CRHEATER101A00 through 119A00,
103B00, 104B00, 113B00 through 116B00, 128B00, and 129B00,
the value in position 9 of the part number differs between the sales
package part number (value is 1 and bare heater model number
(value is 0).
The heaters are modular in design, with heater frames holding
open coil resistance wires strung through ceramic insulators, limit
switches and one or two control contactors. Power conductors are
attached. 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. 18 and 19.) Some heaters
are “keyed” with a restrictor bar on the heater frame or restrictor
plate on the back of the heater mounting plate to be able to go in
only one slot. (See Fig. 13.) These keyed heaters have been
designed and qualified to go only into the designated slot. Do not
remove the key for the purpose of putting the heater in the wrong
slot. Placing a keyed heater in the wrong slot could lead to
overheating and unit damage from the heater not operating
properly.
NOTE: The following heaters do not use the slide track:
CRHEATER101A00-109A00, 297A00, 301A00,
360A00-362A00, 371A00-373A00, 378A00, 379A00.
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 and the unit data
plate for the list of approved heaters. (See Fig. 2 and 3.)
See “Appendix D — ELECTRICAL HEATER DATA” on
page 76 for electric heater module data.
A
L
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ED
P
A
M
O
DE
L
N
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.
E
R
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A
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C
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RP
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11
13
21
23
O
D
2
2
.
2
3
1
2
3
ISTED
AI
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346
N
.
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2
-
56
10
-
4
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V
1
1
1
3
2
1
2
3
Manual Reset
Limit Switch
Control Box
Bushing
Single Point Box
Mounting Screws
Drip Boot Bracket
Mounting Screws
Power Wires
Foam Bushing
Heater Relays
Heater
Mounting
Screws