Electrical Phasing; Variable Speed Manifolded With Fixed Speed Compressors; Precision Suction Restrictor - Trane IntelliPak with Symbio 800 Installation, Operation And Maintenance Manual

Service and Maintenance
Table 69. Oil charge per compressor
Compressor
CSHD103
CSHD075-092
CSHD105-161, VZH088
CSHD175-183, VZH117
CSHN176-315, VZH170
CSHN374
Table 70. Torque requirements for rotolock fittings
CSHD* VZH088 and VZH117
CSHN* and VZH170
Note: Always replace gasket when reassembling oil
equalizer lines.

Electrical Phasing

If it becomes necessary to replace a compressor, it is very
important to review and follow the Electrical Phasing
procedure described in the startup procedure of the IOM.
If the compressors are 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 motor
windings can overheat and cause the motor winding
thermostats to open. This will cause a "compressor trip"
diagnostic and stop the compressor
If a scroll compressor is rotating backwards, it will not pump
and a loud rattling sound can be observed. Check the
electrical phasing at the compressor terminal box. If the
phasing is correct, before condemning the compressor,
interchange any two leads to check the internal motor
phasing.
Variable Speed Manifolded with Fixed
Speed Compressors
Some models use an eFlex™ variable speed compressor
manifolded with a fixed speed compressor. It uses a
patented manifold design that is different from fixed speed
tandems as follows:
1. The variable speed compressor is always first on and
located upstream in the suction line in position 1A;
2. A nozzle in the suction tee, directly upstream of the
manifold set, separates suction oil return to the
upstream variable speed compressor. It also provides a
sump pressure difference to move excess oil from the
variable speed to the fixed speed compressor when
both compressors are running. The nozzle is
specifically sized for this variable speed manifold
compressor combination and must not be removed.
Suction restrictors are not used, and a smaller 3/8" OD
oil equalizer line is used to help maintain the sump
126
Pints
5.0
6.3
7.0
7.6
14.2
15.2
64 +/- 12 ft-lbs
100 +/- 10 ft-lbs
pressure differential.
Figure 93. eFlex variable speed tandem
Fixed
speed
compressor

Precision Suction Restrictor

Tandem manifold compressors that have unequal capacity
sizes use a precision suction restrictor to balance the oil
levels in the compressors (see figure below). This restrictor
is placed in the smaller capacity compressor. When
replacing this compressor, it is imperative that the proper
restrictor is selected from those provided with the
replacement compressor.
When the compressors are restarted, verify that correct oil
levels are obtained with both compressors operating.
Figure 94. Precision suction restrictor
VFD Programming Parameters (Supply/
Condenser for Low Ambient Option)
Units shipped with variable frequency drives (VFD) are
preset and run tested at the factory. If a problem with a
VFD occurs, ensure that the programmed parameters
listed in Table 71, p. 127 and
fan VFDs and Table 73, p. 129
low ambient option is installed), have been set before
replacing the drive.
Verify Parameters
Verify parameter 1-23 is set to motor nameplate frequency.
1. To check parameter 1-23 press the Main Menu button
Nozzle
Inflow
Combined
suction
flow
Variable
speed
compressor
Table 72, p. 129 for supply
for condenser fan VFDs (if
RT-SVX063G-EN