5
To avoid the risk of fire or equipment damage, use copper
conductors.
NOTICE
Units with reciprocating compressors and non-bleed TXV’s require
a Hard Start Kit.
This unit is designed for three phase operation. DO NOT OPERATE
ON A SINGLE PHASE POWER SUPPLY. Measure the power supply to
the unit. The supply voltage must be in agreement with the unit
rating plate power requirements.
RATED
VOLTAGE
MINIMUM SUPPLY
VOLTAGE
MAXIMUM SUPPLY
VOLTAGE
208/230V
197
253
460V
414
506
The condensing unit rating plate lists pertinent electrical data
necessary for proper electrical service and overcurrent protec-
tion. Wires should be sized to limit voltage drop to 2% (max.)
from the main breaker or fuse panel to the condensing unit. Con-
sult the NEC, CEC, and all local codes to determine the correct wire
gauge and length. The wire size must be sufficient to carry the
Minimum Circuit Ampacity (MCA) listed on the serial plate.
The supply voltage can be unbalanced (phase to phase) within
2%. The following formula can be used to determine the percent-
age of voltage unbalance for your unit.
Percentage
Voltage
Unbalance
=
Max. Voltage Deviation From
Average Voltage
Average Voltage
Example:
L1
‐
L2
=
220V
L2
‐
L3
=
216V
Average
Voltage = (220
+
216
+
213)/3
=
649/3
Maximum
Deviation
from
Average
= 220
‐
216
=
4
%
Voltage
Unbalance
= 100
x
(4/216)
= 400/216
10
15
20
25
30
35
40
45
14
75
50
37
NR
NR
NR
NR
NR
12
118
79
59
47
NR
NR
NR
NR
10
188
125
95
75
63
54
NR
NR
8
301
201
150
120
100
86
75
68
6
471
314
235
188
157
134
118
110
*Based on NEC 1996
MAXIMUM ALLOWABLE LENGTH IN FEET
TO LIMIT VOLTAGE DROP TO 2%
Minimum Circuit Ampacity (MCA)
Wire Size
(AWG)
Example:
A
7
½
Ton
unit
is
to
be
installed.
The
distance
from
the
building
to
the
unit
is
75’.
Calculate
the
minimum
wire
size
assuming
no
more
than
2%
voltage
drop.
MCA
for
7
Ton
230V
unit
=
43.3
(from
S&R
plate).
Applying
previous
table
wire
sizes
less
than
#8
AWG
cannot
be
used
for
circuits
which
have
a
rating
of
45A.
The
#8
wire
is
not
suitable
since
the
maximum
length
for
a
45A
circuit
is
68’.
Solution:
Use
a
#6
AWG
wire
suitable
up
to
110’.
NOTE:
It
is
the
contractors’s
responsibility
to
follow
the
NEC
(USA)
or
CEC
(Canada)
when
sizing
the
service
wire
for
this
unit.
½
Local codes often require a disconnect switch located near the
unit; do not install the switch on the unit. Refer to the installation
instructions supplied with the indoor furnace/air handler for spe-
cific wiring connections and indoor unit configuration. Likewise,
consult the instructions packaged with the thermostat for mount-
ing and location information.
Overcurrent Protection
The following overcurrent protection devices are approved for
use.
•
Time delay fuses
•
HACR type circuit breakers
These devices have sufficient time delay to permit the motor-com-
pressor to start and accelerate its load.
Refer to the unit serial plate and this table for the maximum
overcurrent protection permitted.
Run all line voltage wiring a conduit from the service disconnect
box to the unit. Refer to the NEC (USA) or CEC (Canada) codes for
the correct size conduit based on the wire size. The conduit enters
the control box through the hole provided in the bottom. NOTE:
The control box hole is sized for 3/4” conduit. If permitted by
code, a flexible conduit is preferred to minimize vibration trans-
mission from the unit to the building.
Connect the line voltage wires to the L1, L2, and L3 terminals of the
definite purpose contactor (located in the unit control box). Refer
to the wiring diagram attached to the unit when making these
connections.