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Pre-Start
Use the checklist provided below in conjunction with the
General Unit Requirements checklist to confirm the unit is
properly installed and ready for operation.
WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors
before servicing could result in death or serious
injury.
Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. Verify with a CAT III or IV
voltmeter rated per NFPA 70E that all capacitors have
discharged.
•
Check all electrical connections for tightness and point
of termination accuracy.
•
Verify that the condenser airflow will be unobstructed.
WARNING
Rotating Components!
Failure to disconnect power before servicing
could result in rotating components cutting and
slashing technician which could result in death or
serious injury.
During installation, testing, servicing and
troubleshooting of this product it may be
necessary to work with live and exposed rotating
components. Have a qualified or licensed service
individual who has been properly trained in
handling exposed rotating components, perform
these tasks.
•
Verify that the condenser fan and indoor blower turn
freely without rubbing and are properly tightened on the
shafts.
•
Verify that a condensate trap is installed and the piping
is properly sized and pitched.
•
Verify that the correct size and number of filters are in
place.
•
Inspect the interior of the unit for tools and debris and
install all panels in preparation for starting the unit.
Voltage Imbalance
Three phase electrical power to the unit must meet
stringent requirements for the unit to operate properly.
1. Measure each leg (phase-to-phase) of the power
supply. Each reading must fall within the utilization
range stamped on the unit nameplate. If any of the
readings do not fall within the proper tolerances, notify
the power company to correct this situation before
operating the unit.
RT-SVX077B-EN
Excessive three phase voltage imbalance between
phases will cause motors to overheat and eventually
fail. The maximum allowable voltage imbalance is 2
percent.
2. Measure and record the voltage between phases 1, 2,
and 3 and calculate the amount of imbalance as
follows:
% Voltage Imbalance =
AV (Average Voltage) =
•
V1, V2, V3 = Line Voltage Readings
•
VD = Line Voltage reading that deviates the farthest
from the average voltage.
Example: If the voltage readings of the supply power
measured 221, 230, and 227, the average volts would
be:
221 + 230 + 221
= 226 Avg.
3
VD (reading farthest from average) = 221
The percentage of Imbalance equals:
100 + 226 + 221
= 2.2%
226
The 2.2 percent imbalance in this example exceeds the
maximum allowable imbalance of 2.0 percent. This
much imbalance between phases can equal as much
as a 20 percent current imbalance with a resulting
increase in motor winding temperatures that will
decrease motor life.
3.
If the voltage imbalance is over 2 percent, notify the
proper agencies to correct the voltage problem before
operating this equipment.
Electrical Phasing (Three Phase
Motors)
The compressor motor(s) and the supply fan motor are
internally connected for the proper rotation when the
incoming power supply is phased as A, B, C.
Proper electrical supply phasing can be quickly determined
and corrected before starting the unit by using an
instrument such as an Associated Research Model 45
Phase Sequence Indicator and following the steps below.
100 x AV - VD
where;
AV
Volt1 + Volt2 + Volt3
3
35
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