RT-SVX31A-EN28
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.
HAZARDOUS VOLTAGE!
HIGH VOLTAGE IS PRESENT AT THE TERMINAL BLOCK
OR UNIT MOUNTED DISCONNECT SWITCH.
[ ] Check all electrical connections for tightness and “point
of termination” accuracy.
[ ] Verify that the condenser airflow will be unobstructed.
[ ] Verify that the condenser fan and indoor blower turn freely
without rubbing and are properly tightened on the shafts.
[ ] Check the supply fan belts for proper tension and the fan
bearings for sufficient lubrication. If the belts require ad-
justment, or if the bearings need lubricating, refer to the
maintenance section of this manual for instructions.
[ ] 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 in-
stall all panels in preparation for starting the unit.
Voltage Imbalance
Three phase electrical power to the unit must meet strin-
gent requirements for the unit to operate properly. Measure
each leg (phase-to-phase) of the power supply. Each read-
ing 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 cause motors to overheat and eventually fail. The maxi-
mum allowable voltage imbalance is 2%. Measure and
record the voltage between phases 1, 2, and 3 and calcu-
late the amount of imbalance as follows:
% Voltage Imbalance = 100 X
AV - VD
where;
AV
AV (Average Voltage) =
Volt 1 + Volt 2 + Volt 3
3
V1, V2, V3 = Line Voltage Readings
Installation
VD = Line Voltage reading that deviates the farthest from
the average voltage.
Example: If the voltage readings of the supply power
measured 403, 402, and 389, the average volts would be:
403 + 402 + 389 = 398 Avg.
3
VD (reading farthest from average) = 389
The percentage of Imbalance equals:
100 X
398 - 389 = 2.2%
398
The 2.2% imbalance in this example exceeds the maximum
allowable imbalance of 2.0%. This much imbalance be-
tween phases can equal as much as a 20% current imbal-
ance with a resulting increase in motor winding tempera-
tures 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 in-
ternally 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 instru-
ment such as an Associated Research Model 45 Phase Se-
quence Indicator and following the steps below:
[ ] Turn the field supplied disconnect switch that provides
power to the main power terminal 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 termi-
nal 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 switch or
circuit protector switch that provides the supply power to
the unit.
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