Carrier 38AK024-044 - Manual (Page 14)

Initial Check
START-UP
A CAUTION
Do not attempt to start the condensing unit, even mo­
mentarily, until the following steps have been com­
pleted. Compressor damage may result.
1. Check all auxiliary components such as air handling
equipment, and other equipment. Consult the manu­
facturer’s instructions regarding any other equipment
connected to the condensing unit. If used, air flow
switch must be properly installed. See Fig. 9.
2. Backseat (open) compressor suction and discharge
valves. Close valves one turn to allow pressure to reach
test gages.
3. Open liquid line service valve.
4. Set thermostat.
5. Check tightness of all electrical connections.
6. Compressor oil level should be visible in sightglass. See
Service, Oil Charge.
7. Be sure unit is properly leak checked, dehydrated and
charged. See below.
8. Electrical power source must agree with nameplate
rating.
9. Crankcase heater must be firmly locked into compres­
sor crankcase. Be sure crankcase is warm (heater should
be on for 24 hours before starting compressor).
10. Be sure compressor floats freely on the mounting
springs. See Compressor Mounting and Fig. 3 for
loosening compressor bolts.
Leak Test and Dehydration — Leak test the entire
refrigerant system by the pressure method described in the
Carrier Service Techniques Manual, Chapter 1, Section 1-6.
Use R-22 at approximately 25 psig backed up with an inert
gas to a total pressure not to exceed 200 psig.
Preliminary Charge — Refer to Carrier Standard
Service Techniques Manual, Chapter 1, Section 1-8 for
charging methods and procedures. Charge system with
approximately 25 lbs of R-22 by the liquid charging method
and charging by weight procedure.
Start Unit — Close field disconnect, fan circuit breaker
and set thermostat above ambient temperature so that there
is no demand for cooling. Now, only the crankcase heater is
energized. After the heater has been on for 24 hours, the unit
can be started. If no time has elapsed since the preliminary
charge step has been completed, it is unnecessary to wait the
24-hour period.
Close the compressor circuit breaker, then reset the
indoor thermostat below ambient temperature, so that a call
for cooling is ensured.
NOTE: Do not use the compressor circuit breaker to start
and stop compressor, except in an emergency.
Depending on the position of the Time Guard timer,
start-up of the compressor occurs within 12 seconds and 8
minutes from the time the control circuit is energized.
Charge System — Actual start-up should be done only
under supervision of a qualified refrigeration mechanic.
Refer to charging charts.
See Fig. 10 through 13 for the particular unit being
charged. Measure pressure at the liquid line service valve,
being sure a Schrader depressure is used if required. Also,
measure liquid line temperature as close to the liquid service
valve as possible. Add charge until the pressure and
temperature conditions of the charging chart curve are met.
If liquid pressure and temperature point fall below curve,
add charge. If liquid pressure and temperature point fall
below curve, reduce the charge until the conditions match
the curve.
A CAUTION
Never charge liquid into the low-pressure side of
system. Do not overcharge. During charging or
removal of refrigerant, be sure indoor fan system is
operating.
Operation — Refer to control circuit diagram on the unit,
or in the unit wiring book.
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