Starting 40 To 50 Ton Standard Efficiency Vav Units; Starting 27.5-50 Tons High Efficiency; Units And 40-50 Tons Standard; Units - Trane Voyager Commercial Installation, Operation And Maintenance Manual

S S t t a a r r t t u u p p
I I m m p p o o r r t t a a n n t t : : The compressors are protected from
reverse rotation caused by improper
sequencing of the customer supplied unit
power wires by the unit phase monitor. It is
imperative to verify correct sequencing of
compressor power wires to prevent
compressor failure from reverse rotation.
Refer to the unit wiring schematic and/or
wire color markers vs. the compressor
terminal block color markers.
Figure 63. Compressor terminal block color markers
If a scroll compressor is rotating backwards, it will not
pump and a loud rattling sound can be observed. If
allowed to run backward for even a very short period of
time, internal compressor damage may occur and
compressor life may be reduced. If allowed to run
backwards for an extended period of time, the
compressor will likely fail or the motor windings will
overheat and cause the motor winding thermostats to
open. The opening of the motor winding thermostat
will cause a "compressor trip" diagnostic and stop the
compressor.
Starting 40 to 50 Ton Standard Efficiency
VAV Units
Install a set of service gauges onto the suction and
discharge service ports of each circuit. Follow the same
procedures as above to start the first stage of
compressor operation.
After the compressor and the condenser fans have
been operating for approximately 30 minutes, use
91 through Figure 97, p. 104
operating pressures for that circuit.
Jump across the "Test Terminals" once again. This will
allow the second stage compressors to start. The first
stage compressor will shut off providing the 3 minute
"On" time has elapsed.
N N o o t t e e : : When the second refrigerant circuit is requested
to operate, both compressors of the 50 ton unit
will run simultaneously. Verify that the
compressors are rotating in the correct direction.
Observe the operation of the compressor(s) and the
system operating pressures. After compressors and
condenser fans for the circuit have been operating for
approximately 30 minutes, use
90
, p.
to determine the proper
, p. 91 through Figure
97, p. 104 to determine the proper operating pressures.
For subcooling guidelines, refer to
Subcooling," p. 105.
Units with Lead/Lag function disabled, jump across the
"Test Terminals" once again. This will allow the third
stage of cooling (number one circuit) to start providing
the 3 minute "Off" time has been satisfied.

Starting 27.5-50 Tons High Efficiency

Units and 40-50 Tons Standard Efficiency
Constant Volume Units
Install a set of service gauges onto the suction and
discharge service ports of the circuit. Jump across the
"Test Terminals" on LTB1 or toggle the test switch
three consecutive times if it is a constant volume
application, or five times if it is a variable air volume
application for two to three seconds per jump in order
to get to cooling stage 1.
Jump across the "Test Terminals" two more times for
full load cooling. After the compressor and the
condenser fans have been operating for approximately
30 minutes, use , p. 91 through
determine the proper operating pressures for that
circuit.
For subcooling guidelines, refer to
Subcooling," p. 105.

Line Weights

The standard and high efficiency units use line weights
to dampen vibration. Do not remove, relocate, or over-
torque these weights. The torque specification for the
attaching bolts is 6 ft-lbs ± 1.0 ft-lb.
The locations of the line weights are shown in the
following figures.
Figure 64. Line weight locations TE, YC, TC*330, 360,
and 420 standard efficiency w/o service valves
0.75±0.25
"Measuring
Figure 97, p. 104 to
"Measuring
0.75±0.25
RT-SVX34R-EN