Trane R Series Installation Operation & Maintenance page 95

95
Pre-Start Checkout
result from untreated or improperly
treated water, or saline or brackish
water.
CAUTION
Use Piping Strainers!
To prevent evaporator damage, pipe
strainers must be installed in the wa-
ter supplies to protect components
from water born debris. Trane is not
responsible for equipment-only-dam-
age caused by water born debris.
6. Close the fused-disconnect switch(es)
that supplies power to the chilled water
pump starter.
7. Start the chilled water pump to begin
circulation of the water. Inspect all pip-
ing for leakage and make any necessary
repairs.
8. With water circulating through the sys-
tem, adjust water flow and check water
pressure drop through the evaporator.
9. Adjust the chilled water flow switch for
proper operation.
10. Reapply power to complete proce-
dures.
11. Prove all Interlock and Interconnect-
ing Wiring Interlock and External as de-
scribed in the Electrical Installation sec-
tion.
12. Check and set, as required, all
CH530 menu items.
13. Stop the chilled water pump.
14. Energize compressor and oil separa-
tor heaters 24 hours prior to unit start-up.
Unit Voltage Power Supply
Voltage to the unit must meet the criteria
given in the Installation-Electrical Sec-
tion. Measure each leg of the supply
voltage at the unit's main power fused-
disconnect. If the measured voltage on
any leg is not within specified range, no-
tify the supplier of the power and correct
the situation before operating the unit
CAUTION
Equipment Damage!
Provide adequate voltage to the unit.
Failure to do so can cause control
components to malfunction
shorten the life of relay contact, com-
pressor motors and contactors.
Unit Voltage Imbalance
Excessive voltage imbalance between
the phases of three-phase system can
cause motors to overheat and eventually
fail. The maximum allowable imbalance
is 3%. Voltage imbalance is determined
using the following calculations:
% Imbalance = [(Vx - V ave) x 100]/Vave
V ave = (V1 + V2 + V3)/3
Vx = phase with the greatest difference
from V ave (without regard to the sign)
For example, if the three measured volt-
ages are 221, 230, and 227 volts, the
average would be:
(221+230+227)/3 = 226
The percentage of the imbalance is then:
[100(221-226)]/226 = 2.2%
This exceeds the maximum allowable
(2%) by 0.2 percent.
Unit Voltage Phasing
CAUTION
Compressor Damage!
It is imperative that L1, L2, L3 in the
starter be connected in the A-B-C
phase sequence to prevent equip-
ment damage due to reverse rotation.
It is important that proper rotation of
the compressors be established before
the unit is started. Proper motor rota-
tion requires confirmation of the electri-
cal phase sequence of the power sup-
ply. The motor is internally connected
for clockwise rotation with the incoming
power supply phased A, B, C.
Basically, voltages generated in each
phase of a polyphase alternator or circuit
are called phase voltages. In a three-
phase circuit, three sine wave voltages
are generated, differing in phase by 120
electrical degrees. The order in which
the three voltages of a three-phase
system succeed one another is called
phase sequence or phase rotation. This
is determined by the direction of rotation
of the alternator. When rotation is clock-
wise, phase sequence is usually called
"ABC," when counter clock-wise, "CBA."
This direction may be reversed outside
the alternator by interchanging any two
of the line wires. It is this possible inter-
change of wiring that makes a phase
sequence indicator necessary if the op-
erator is to quickly determine the phase
rotation of the motor.
and
Proper compressor motor electrical
phasing can be quickly determined and
corrected before starting the unit. Use a
quality instrument, such as the Associat-
ed Research Model 45 Phase Sequence
Indicator, and follow this procedure.
1. Press the STOP key on the CH530.
RTAC-SVX002A-EN