Instruction manual
when the outdoor temperature is below 40° F (unless accessory
low-ambient kit is installed). Do not rapid-cycle the compressor.
Allow 5 minute between “on” cycles to prevent compressor
damage.
A. CHECKING COOLING AND HEATING
CONTROL OPERATION
Start and check the unit for proper control operation as follows:
1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is
placed in ON position and shuts down within 60 sec. when
FAN switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch
in AUTO position. Set control below room temperature.
Observe that cooling cycle shuts down when control setting
is satisfied.
3. Place system switch in HEAT position. Set control above
room temperature. Observe that compressor, outdoor fan,
and indoor blower motors start. Observe that heating cycle
shuts down when control setting is satisfied.
4. When using an automatic changeover room thermostat,
place both SYSTEM and FAN switches in AUTO positions.
Observe that unit operates in Cooling mode when tempera-
ture control is set to “call for Cooling” (below room
temperature), and unit operates in Heating mode when
temperature control is set to “call for Heating” (above room
temperature).
IMPORTANT: Three-phase, scroll compressors are direction
oriented. Unit must be checked to ensure proper compressor
3-phase power lead orientation. If not corrected within 5 minute,
the internal protector will shut off the compressor. The 3-phase
power leads to the unit must be reversed to correct rotation. When
turning backwards, scroll compressors emit elevated noise levels,
and the difference between compressor suction and discharge
pressures may be dramatically lower than normal.
B. CHECKING AND ADJUSTING REFRIGERANT
CHARGE
The refrigerant system is fully charged with R-22 refrigerant and
is tested and factory sealed. Allow system to operate a minimum
of 15 minutes before checking or adjusting charge.
NOTE: Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R-22 charge.
The charging label and the tables shown refer to system tempera-
tures and pressures in cooling mode only. A refrigerant charging
label is attached to the outside of the service access door. If charge
level is suspect in Heating mode, reclaim all refrigerant and charge
to nameplate amount. (This information may be obtained from the
physical data table also.)
IMPORTANT: When evaluating the refrigerant charge, an indi-
cated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as insuf-
ficient airflow across either coil or both coils.
C. REFRIGERANT CHARGE
The amount of refrigerant charge is listed on the unit nameplate
and/or the physical data table. Refer to the Refrigeration Service
Techniques Manual, Refrigerants Section.
D. NO CHARGE
Check for leak. Use standard evacuating techniques. After evacu-
ating system to 500 microns, weigh in the specified amount of
refrigerant (refer to system data plate).
E. LOW CHARGE COOLING
Use Cooling Charging Charts (Fig. 26-38). Vary refrigerant until
the conditions of the chart are met. Note that charging charts are
different from type normally used. Charts are based on charging
the units to correct superheat for the various operating conditions.
Accurate pressure gage and temperature sensing devices are
required. Connect the pressure gage to the service port on the
suction line. Mount the temperature sensing device on the suction
line and insulate it so that the outdoor ambient does not affect the
reading. Indoor air CFM must be within the normal operating
range of the unit.
F. TO USE COOLING CHARGING CHARTS
Take the outdoor ambient temperature and read the suction
pressure gage. Refer to the chart to determine what the suction
temperature should be.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
Fig. 19—Control Wiring Plate
C99070
24 V Circuit Breaker
24 Volt Compartment
Fig. 20—Transformer Label
C99058
TRANSFORMER CONTAINS A MANUAL
RESET OVERCURRENT PROTECTOR
IT WILL NOT AUTOMATICALLY RESET
DISCONNECT POWER AND INSTALL
LOCKOUT TAG PRIOR TO SERVICING
THIS COMPARTMENT MUST BE CLOSED
EXCEPT WHEN SERVICING
Fig. 21—Fan Blade Clearance
C99009
FAN GRILLE
MOTOR
1/8" MAX BETWEEN
MOTOR AND FAN HUB
MOTOR SHAFT
1/2˝
—17—