40 RT-SVX46G-EN
Pre-Start
Use the checklist provided below in conjunction with the
“General Unit Requirements” checklist to ensure that the
unit is properly installed and ready for operation.
Verify that the condenser airflow will be unobstructed.
• Verify that the condenser fan and indoor blower turn
freely with
out rubbing and are properly tightened on
the shafts.
• Verify that a condensate trap is installed and the piping
is pro
perly 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
in
stall 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.
Measure each leg (phase-to-phase) of the power supply.
E
ac
h 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.
Excessive three phase voltage imbalance between phases
will cau
se mo
tors to overheat and eventually fail. The
maximum allowable voltage imbalance is 2%. Measure
and record the voltage between phases 1, 2, and 3 and
calculate the amount of imbalance as follows:
V1, V2, V3 = Line Vo
ltage
Readings
VD = Line Voltage reading that deviates the farthest from
the averag
e voltage.
Example: If the voltage readings of the supply power
measured 221, 230, and 227, the average volts would be:
VD (reading farthest from
average) = 221
The percentage of imbalance equals:
The 2.2% imbalance in this example exceeds the
maximum allowable imbalance of 2.0%. This much
imbalance between phases can equal as much as a 20%
current imbalance with a resulting increase in motor
winding temperatures that will decrease motor life. If the
voltage imbalance is over 2%, 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
d
eter
mined 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:
• Turn the field supplied disconnect switch that provides
power to the
main power termin
al block or to the
“Line” side of the optional factory mounted disconnect
switch to the “Off” position.
• Connect the phase sequence indicator leads to the
ter
mina
l block or to the “Line” side of the optional
factory mounted disconnect switch as follows;
Black (phase A) to L1
Red (phase B) to L2
Yellow (phase C) to L3
• Close the field supplied main power disconnect sw
itch
or ci
rcuit protector switch that provides the supply
power to the unit.
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 an appropriate
voltmeter that all capacitors have discharged.
For additional information regarding the safe discharge
of capacitors,
see PROD-SVB06A-EN.
WARNING
Rotating Components!
Failure to follow all safety precautions below 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.
% Voltage Imbalance=
100 x AV - VD
where;
AV
AV (Average Voltage)=
Volt 1 + Volt 2 + Volt 3
3
221 + 230 + 227
= 226 Avg.
3
100 x 226 - 221
= 2.2%
226
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