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START-UP
I. START-UP AND ADJUSTMENTS
CAUTION:
Complete the required procedures given
in the Pre-Start-Up section 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 25 F (Ϫ4 C) (unless accessory low am-
bient kit is installed).
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 posi-
tion. 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 and condenser- and
evaporator-fan motors start. Observe that cooling cycle
shuts down when control setting is satisfied.
B. Unit Controls
All units have the following internal-protection controls:
Compressor Overload
This overload interrupts power to the compressor when
either the current or internal motor winding temperature be-
come excessive, and automatically resets when the internal
temperature drops to a safe level. This overload may require
up to 60 minutes (or longer) to reset. If the internal overload
is suspected of being open, disconnect the electrical power to
the unit and check the circuit through the overload with an
ohmmeter or continuity tester.
Time Guard II Device
The unit is equipped with accessory Time Guard II recycle
timer. The device will cause a 5-minute delay between com-
pressor starts.
Cycle-LOC™ Device
When high-pressure or low-pressure fault occurs, the Cycle-
LOC device will protect the system by not allowing the com-
pressor to start.
Low-Pressure/Loss of Charge Switch (LPS)
When the liquid line pressure drops below 7 psig (48 kPa),
the LPS opens 24-v power to the compressor contactor and
stops the compressor. When the pressure reaches 22 psig
(152 kPa), the switch resets and the compressor is allowed to
restart.
High-Pressure Switch (HPS)
When the refrigerant high-side pressure reaches 426 psig
(2937 kPa), the HPS opens 24-v power to the compressor con-
tactor and stops the compressor. When the pressure drops to
320 psig (2206 kPa), the switch resets and the compressor is
allowed to restart.
C. Sequence of Operation
At start-up, the thermostat calls for cooling. When all safety
devices are satisfied, the compressor contactor (fan con-
tactor) will energize causing the compressor and outdoor (con-
denser) fan motor to operate. Terminal ЉGЉ at the thermostat
is also energized, allowing the field-supplied and -installed
(24v) indoor (evaporator) fan contactor to function. A field-
supplied and -installed liquid line valve (connected between
Terminals G and C) will also open, allowing the system to
function in cooling. As cooling demand is satisfied, the ther-
mostat contacts break, deenergizing the contactor causing the
system to shut off. The liquid line solenoid (LLS) valve closes,
minimizing the potential for refrigerant migration at this time.
The compressor does not restart until the thermostat again
calls for cooling. If a demand for cooling occurs within 5 min-
utes after the thermostat is satisfied, the system will not re-
start due to the feature of Time Guard II device. After the
5-minute time period, the system will restart as normal upon
thermostat demand.
The system is protected with a Cycle-LOC device so that the
compressor will not start if a high-pressure or low-pressure
fault occurs. To reset the Cycle-LOC device, set the thermo-
stat to eliminate the cooling demand then return to the origi-
nal set point. This should be done only once, and if system
shuts down due to the same fault, determine the problem be-
fore attempting to reset the Cycle-LOC device.
The crankcase heaters must be energized for a minimum of
24 hours before starting a 569C and 576B unit.
D. Oil Charge
576B Units
Allow unit to run for about 20 minutes. Stop unit and check
compressor oil level. Add oil only if necessary to bring oil into
view in sight glass. Use only approved compressor oil.
Approved oils are:
Suniso 3GS
WF32-150
If oil is added, run unit for an additional 10 minutes. Stop
unit and check oil level. If level is still low, add oil only after
determining that piping system is designed for proper oil re-
turn and that system is not leaking oil.
569C Units
The 569C units do not have a sight glass and are factory charged
with the correct amount of oil.
All Units
Do not reuse drained oil or use any oil that has been exposed
to the atmosphere. Procedures for adding or removing oil are
given in the Standard Service Techniques Manual, Chapter 1,
Refrigerants.
CARE AND MAINTENANCE
To ensure continuing high performance and to minimize the
possibility of premature equipment failure, periodic mainte-
nance must be performed on this equipment. This cooling unit
should be inspected at least once each year by a qualified serv-
ice person.
NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
WARNING:
The ability to properly perform mainte-
nance on this equipment requires certain expertise,
mechanical skills, tools, and equipment. If you do not
possess these, do not attempt to perform any mainte-
nance on this equipment other than those procedures
recommended in the User’s Manual. FAILURE TO HEED
THIS WARNING COULD RESULT IN SERIOUS PER-
SONAL INJURY AND POSSIBLE DAMAGE TO THIS
EQUIPMENT.
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