20
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 distribution and fuse
blocks. The single point box will be insta lled di r ectly
under the unit control box, just to the left of the partition
separating the indoor section (with elec tric heaters) from
the outdoor section. The Single Point Box has a hinged
access cover. See Fig. 30. 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 i nstructions for deta ils on tap
connec tions.
All fuses on 50TC units are 60--A. (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.)
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 installation
instructions for details on tap c onnections.
A
L
LIE
D
P
A
M
O
DE
L
NO
.
ER
I
A
L
N
O.
C
O
R
P
.
O
D
2
2
.
2
3
1
2
3
ISTED
AI
R
NDITIONIN
G
UI
P
ACCES
S
346
N
.
P
/
N
2
-
5
6
1
0
-
4
RE
V
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
C14253
Fig. 30 -- Typical Single Point Installation
Low--Voltage Control Connections —
Pull the low--voltage control lea ds from the heater
module(s) -- VIO a nd BRN (two of each if two modules
are installed; identify for Module #1) -- to the 4--pole
terminal board TB4 located on the heater bulkhead to the
left of Heater #1. Connect the VIO lead from Heater #1 to
terminal TB4--1. Except for CRHEATER128B00--129B00,
for 2 stage heating, connect the VIO lead from Heater #2
to terminal TB4 --2. For 1 stage heating with 2 heater
modules connect the VIO lead from both Heater #1 and #2
to terminal TB4 --1. Connect both BRN leads to terminal
TB4--3. See Fig. 31.
ORN
BRN
Field
Connections
HR1: On Heater 1 in Position #1
HR2: On Heater 2 in Position #2 (if installed)
2
3
12
13
VIO
ORN
VIO
BRN
VIO
BRN
BRN
VIO
2
TB4
VIO
HR2
HR1
BRN
VIO
BRN
Elec Htr
CTB
CONTL
BOARD
C08331
Fig. 31 -- Accessory Electric Heater Control
Connections (Except CRHEATER128B00--129B00)
For CRHEATER128B00--129B00 only
— Connect the
ORN lead from Heater Relay 1 (HR1) to terminal TB4--1.
For 2 stage heating connect the VIO lead from Heater
Relay 3 (HR3) to terminal TB4--2. For 1 stage heating
with CRHEATER128B00 or CRHEATER129B00 connect
the ORN lead from HR1 and the VIO lead from HR3 to
terminal TB4-- 1. Connect the BRN lead from HR1 to
TB4--3. See Fig. 32.
CTB
CONTL
BOARD
ORN
BRN
Field
Connections
LS: Primary Limit Switch
2
3
12
31
VIO
ORN VIO BRN
BRNVIO
2
TB4
VIO
HR3
HR1
ORN BRN
Elec Htr
ORN
For simplicity, not all control
wiring internal to the electric
heaters is shown.
LS
a50--- 9606
Fig. 32 -- Accessory Electric Heater Control
Connections for CRHEATER128B00--129B00 Only
50TC
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