Specifications
Page 12
III-ELECTRICAL CONNECTIONS
A-Power Supply
Refer to startup directions and refer closely to the unit wir
ing diagram when servicing. See unit nameplate for mini
mum circuit ampacity and maximum fuse size.
208/460/575 volt units are factory wired with red wire con
nected to control transformer primary. 230 volt units are
field wired with orange wire connected to control trans
former primary.
IV-PLACEMENT AND INSTALLATION
Make sure that the unit is installed in accordance with the
installation instructions and all applicable codes. See ac
cessories section for conditions requiring use of the op
tional roof mounting frame (RMF16).
V-STARTUP - OPERATION
A-Preliminary and Seasonal Checks
1- Make sure the unit is installed in accordance with the
installation instructions and applicable codes.
2- Inspect all electrical wiring, both field and factory
installed for loose connections. Tighten as required.
Refer to unit diagram located on inside of unit control
box cover.
3- Check to ensure that refrigerant lines are in good con
dition and do not rub against the cabinet or other re
frigerant lines.
4- Check voltage at the disconnect switch. Voltage must
be within the range listed on the nameplate. If not, con
sult the power company and have the voltage cor
rected before starting the unit.
5- Recheck voltage and amp draw with unit running. If
power is not within range listed on unit nameplate,
stop unit and consult power company. Refer to unit
nameplate for correct running amps.
6- Inspect and adjust blower belt (see section
VII-C-Blower Belt Adjustment).
B-Cooling Startup
NOTE-The following is a generalized procedure and
does not apply to all thermostat control systems. Elec
tronic and ramping thermostat control systems may op
erate differently. Refer to the operation sequence sec
tion of this manual for more information.
WARNING
Crankcase heaters must be energized for 24
hours before attempting to start compressors.
Set thermostat so there is no compressor demand
before closing disconnect switch. Attempting to
start compressors during the 24hour warmup
period could result in damaged or failed compres
1- Set fan switch to AUTO or ON and move the system
selection switch to COOL. Adjust the thermostat to a
setting far enough below room temperature to bring
on all compressors. Compressors will start and cycle
on demand from the thermostat (allowing for unit and
thermostat time delays).
2- Each refrigerant circuit is charged with R-22 refrigerant.
See unit rating plate for correct charge amount.
3- Refer to Cooling Operation and Adjustment section
for proper method of checking charge.
C-Heating Startup
1 Set the fan switch to AUTO or ON and move the sys
tem selection switch to HEAT. Adjust the thermostat
setting above room temperature.
2 The indoor blower and first stage gas heat immediate
ly start.
3 Additional stages are controlled by indoor thermostat.
D-Safety or Emergency Shutdown
Turn off power to the unit.
VI-COOLING SYSTEM SERVICE CHECKS
GCS24 is factory charged and requires no further adjustment;
however, charge should be checked periodically using the ap
proach method. The approach method compares actual liq
uid temperature with the outdoor ambient temperature. Ther
mometer wells have been provided to allow accurate liquid
temperature measurement.
A-Gauge Manifold Attachment
Service gauge ports are identified in figure 5. Attach high
pressure line to liquid line gauge port on thermometer well. At
tach low pressure line to suction line service port.
NOTE-When unit is properly charged liquid line pressures
should approximate those in table 2.
B-Charging
All units are factory charged and require no further adjust
ment; however, check charge during start-up using the ap
proach method outlined below. Approach method compares
actual liquid temperature with outdoor ambient temperature.
Thermometer wells have been provided to allow accurate liq
uid temperature measurement.
If the system is completely void of refrigerant, the recom
mended and most accurate method of charging is to weigh
refrigerant into the unit according to the amount shown on the
unit nameplate and in the specifications table. If weighing fa
cilities are not available or if the unit is just low on charge, use
the following procedures: