Operating instructions
2. Connect ground lead to chassis ground connection.
3. Locate the black and yellow wires connected to the lines side
of the contactor.
4. Connect field L1 to black wire on connection 11 of the
compressor contactor.
5. Connect field wire L2 to yellow wire on connection 13 of the
compressor contactor.
6. Connect field wire L3 to Blue wire from compressor.
SPECIAL PROCEDURES FOR 208-V OPERATION
Before making any wiring changes, make sure the gas supply
is switched off first. Then switch off the power supply to the
unit and install lockout tag. Electrical shock can cause serious
injury or death.
CONTROL VOLTAGE CONNECTIONS
Do not use any type of power-stealing thermostat. Unit control
problems may result.
Use no. 18 American Wire Gage (AWG) color-coded, insulated
(35 C minimum) wires to make the control voltage connections
between the thermostat and the unit. If the thermostat is located
more than 100 ft from the unit (as measured along the control
voltage wires), use no. 16 AWG color-coded, insulated (35 C
minimum) wires.
Standard Connection
Remove knockout hole located in the flue panel adjacent to the
control access panel (See Fig. 2 and 3). Remove the rubber
grommet from the installer’s packet (included with unit) and install
grommet in the knockout opening. Provide a drip loop before
running wire through panel.
Run the low-voltage leads from the thermostat, through the inlet
hole, and into unit low-voltage splice box.
Locate five 18-gage wires leaving control box. These low-voltage
connection leads can be identified by the colors red, green, yellow,
brown, and white (See Fig. 11). Ensure the leads are long enough
to be routed into the low-voltage splice box (located below right
side of control box). Route leads through hole in bottom of control
box and make low-voltage connections (See Fig. 11). Secure all
cut wires, so that they do not interfere with operation of unit.
HEAT ANTICIPATOR SETTING
The room thermostat heat anticipator must be properly adjusted to
ensure proper heating performance. Set the heat anticipator, using
an ammeter between the W and R terminals to determine the exact
required setting.
NOTE: For thermostat selection purposes, use 0.18 amp for the
approximate required setting. Failure to make a proper heat
anticipator adjustment will result in improper operation, discom-
fort to the occupants of the conditioned space, and inefficient
energy utilization; however, the required setting may be changed
slightly to provide a greater degree of comfort for a particular
installation.
TRANSFORMER PROTECTION
The transformer is of the energy-limiting type. It is set to
withstand a 30-sec. overload or shorted secondary condition.
Table 4—Legend
C99024
452=5v
457=7v
455=2v
LEGEND
FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps
NOTES:
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NEC
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power Supply fuse. Canadian units may be
fuse or circuit breaker.
2. Minimum wire size is based on 60 C copper wire. If other than
60 C wire is used, or if length exceeds wire length in table,
determine size from NEC.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%.
Use the following formula to determine
the percentage of voltage imbalance.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
average voltage
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
452 + 464 + 455
Average Voltage =
3
1371
=
3
= 457
Determine maximum deviation from average voltage.
(AB) 457
(BC) 464
(AC) 457
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
®
CKT BKR
—
Circuit Breaker
13