Startup
RT-SVX34F-EN
77
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.
Note:
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
Table 61, p. 79
through
Table 71, p. 84
to determine the proper operating
pressures. For subcooling guidelines, refer to “Checking
Subcooling” at the end of this section.
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.
The 40 and 50 ton units employ the use of 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 location of the line weights is shown in
Figure 57,
p. 77
, and
Figure 58, p. 77
.
Compressor Oil
Once all of the compressors have been started, verify that
the oil level is visible through the sight glass or above the
sight glass. Use appropriate lighting (flash light) to verify
the presence of oil. A tandem manifold set may have
different oil heights, but still must be visible in the sight
glass or above the sight glass.
After shutting the compressors off, check the oil’s
appearance. Discoloration of the oil indicates that an
abnormal condition has occurred. If the oil is dark,
overheating may have occurred. Potential causes of
overheating: compressor is operating at extremely high
condensing temperatures; high superheat; a compressor
mechanical failure; or, occurrence of a motor burnout. If
the oil is black and contains metal flakes, a mechanical
failure has occurred. This symptom is often accompanied
by a high compressor amperage draw.
Refer to the Refrigeration system in the maintenance
section for details on testing and replacing oil.
Figure 57.
Line weight locations — 50 Ton
Figure 58.
Line weight locations — 40 Ton