Maintenance
102
RT-SVX34F-EN
test kits must be used for POE oil (OIL00079 for a quart
container or OIL00080 for a gallon container) to determine
whether the oil is acid.
If a motor burn out has occurred, change the oil in both
compressors in a tandem set. This will require that the oil
equalizer tube be removed to suck the oil out of the oil
sump. A catch pan must be used to catch the oil when the
compressor oil equalizer line is loosened.
Note:
Refrigerant oil is detrimental to some roofing
materials. Care must be taken to protect the roof
from oil leaks or spills.
Charge the new oil into the Schrader valve on the shell of
the compressor. Do to the moisture absorption properties
of POE oil, do not use POE oil from a previously opened
container. Also discard any excess oil from the container
that is not used.
Compressor Replacements
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 this
manual.
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.
Precision Suction Restrictor
Tandem manifold compressors that have unequal
capacity sizes utilize a precision suction restrictor
Figure 63
to balance the oil levels in the compressors. 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. See
Table 76, p. 102
and
Figure 64
.
When the compressors are restarted, verify that correct oil
levels are obtained with both compressors operating.
Compressor model
Oil amount
CSHD142-161 7.0
pts
CSHD183
7.6 pts
CSHN250 14.2
pts
Figure 63.
Precision suction restrictor
Table 76.
Compressor models/restrictor locations
Restrictor
Location
Model
T**/Y**
Compres
sor CPR3
Compres
sor CPR2
Compres
sor CPR1 CPR3 CPR2 CPR1
330
CSHD142
CSHD161
X
420
CSHD161
CSHD184
X
600
CSHD155
CSHD183
CSHD161
X
Figure 64.
Compressors
