erant leak. Leak-test all refrigerant tubing connections
using electronic leak detector, or liquid-soap solution. If
a refrigerant leak is detected, see following Check for
Refrigerant Leaks section.
c. Inspect all field- and factory-wiring connections. Be sure
that connections are completed and tight.
d. Inspect coil fins. If damaged during shipping and han-
dling, carefully straighten fins with a fin comb.
3. Verify the following conditions:
a. Make sure that outdoor-fan blade is correctly positioned
in fan orifice. Top edge of blade should be 3.125 in.
down from condenser outlet grille. See Condenser Fan
section in this publication.
b. Make sure that air filter is in place.
c. Make sure that condensate drain pan and trap are filled
with water to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.
START-UP
Use the Start-Up Checklist supplied at the end of this book, and
proceed as follows:
I.
CHECK FOR REFRIGERANT LEAKS
A.
Locate and repair refrigerant leaks and charge the
unit as follows:
1. Using both high- and low-pressure ports, locate leaks and
reclaim remaining refrigerant to relieve system pressure.
2. Repair leak following accepted practices.
NOTE:
Install a filter drier whenever the system has been opened
for repair.
3. Check system for leaks using an approved method.
4. Evacuate refrigerant system and reclaim refrigerant if no
additional leaks are found.
5. Charge unit with R-22 refrigerant, using a volumetric-
charging cylinder or accurate scale.
Refer to unit rating
plate for required charge.
Be sure to add extra refrigerant to
compensate for internal volume of field-installed filter
drier.
II.
START-UP COOLING SECTION AND MAKE ADJUST-
MENTS
CAUTION:
Complete the required procedures given in
the Pre-Start- Up section this page before starting the
unit.
Do not jumper any safety devices when operating the
unit.
Do not operate the compressor when the outdoor tem-
perature is below 40 F.
Do not rapid-cycle the compressor. Allow 5 minutes
between ‘‘on’’ cycles to prevent compressor damage.
A.
CHECKING COOLING CONTROL OPERATION
Start and check the unit for proper cooling 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 when FAN switch is
placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch
in AUTO position. Set cooling control below room tem-
perature. Observe that compressor, condenser fan, and
evaporator blower motors start. Observe that cooling cycle
shuts down when control setting is satisfied.
3. When using an automatic changeover room thermostat,
place both SYSTEM and FAN switches in AUTO. posi-
tions. Observe that unit operates in Cooling mode when
temperature control is set to ‘‘call for cooling’’ (below
room temperature).
III.
REFRIGERANT CHARGE
Amount of refrigerant charge is listed on unit nameplate (also refer
to Table 1). Refer to Carrier Refrigerant Service Techniques
Manual, Refrigerants section.
Unit panels must be in place when unit is operating during
charging procedure.
A.
NO CHARGE
Use standard evacuating techniques. After evacuating system,
weigh in the specified amount of refrigerant (refer to Table 1).
B.
LOW CHARGE COOLING
Use Cooling Charging Charts, Fig. 17-20. Vary refrigerant until
the conditions of the appropriate chart are met. Note that charging
charts are different from the type normally used. Charts are based
on charging the units to the correct superheat for the various
operating conditions. Accurate pressure gauge and temperature
sensing device are required.
To measure suction pressure, perform the following:
1. Connect the pressure gauge to the service port on the
suction line.
2. Mount the temperature sensing device on the suction line
and insulate it so that outdoor ambient temperature does not
affect the reading. Indoor air cfm must be within the normal
operating range of the unit.
C.
TO USE COOLING CHARGING CHARTS
1. Take the outdoor ambient temperature and read the suction
pressure gauge.
Fig. 11—Control Box Wiring
C00011
ELECTRIC
HEATER
FUSES
GROUND
LUG
INDOOR
FAN
RELAY
OUTDOOR FAN MOTOR
AND COMPRESSOR
START CAPACITOR
HIGH
VOLTAGE
LEADS
—9—
