Page 27
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
sors.
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
4- Set the fan switch to AUTO or ON and move the sys
tem selection switch to HEAT. Adjust the thermostat
setting above room temperature.
5- The indoor blower and first stage electric heat immedi
ately start.
6- Additional stages are controlled by indoor thermostat
and electric heat time delays.
D-Safety or Emergency Shutdown
Turn off power to the unit.
VI-COOLING SYSTEM SERVICE CHECKS
CHA16 is factory charged and requires no further adjust
ment; however, charge should be checked periodically us
ing the approach method. The approach method
compares actual liquid temperature with the outdoor ambi
ent temperature. Thermometer wells have been provided
to allow accurate liquid temperature measurement.
A-Gauge Manifold Attachment
Service gauge ports are identified in figures 14, 15, 16, 17
and 18. Attach high pressure line to liquid line gauge port
on thermometer well. Attach low pressure line to suction
line service port.
NOTE-If owner complains of insufficient cooling, the unit
should be gauged and refrigerant charge checked.
B-Charging
All units are factory charged and requires no further ad
justment; however, check charge during start-up using
the approach method outlined below. Approach meth
od compares actual liquid temperature with outdoor
ambient temperature. Thermometer wells have been
provided to allow accurate liquid temperature mea
surement.
If the system is completely void of refrigerant, the rec
ommended 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 facilities are not available or if the unit
is just low on charge, use the following procedures:
To Next Page
Loading...
Need help?
General
