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RT-SVX073A-EN
• High superheat
• A compressor mechanical failure
• Occurrence of a motor burnout.
If a motor burnout is suspected, use an acid test kit
(KIT15496) to check the condition of the oil. Test results will
indicate an acid level has exceeded the limit if a burnout
occurred. Oil 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 acidic. If a motor burnout has
occurred, change the oil in both compressors in a tandem
set.
CSHN/CSHL Compressors
CSHN/CSHL compressors have an oil drain valve which
allows the oil to be drained out of the compressor. After the
refrigerant has been recovered, pressurize the system with
nitrogen to help remove the oil from the compressor.
Figure 116. PTFE gasket
Charge the new oil into the Schrader valve or oil drain valve
on the shell of the compressor. Due 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.
Figure 117. CSHN/CSHL
Oil equalizer Rotolock
connection fitting
¼ Schrader port
Oil drain valve
VZH Variable Speed Compressors
Refer to “Service and Maintenance_CSHN
Compressors,” p. 178 for VZH117 oil removal procedures.
VZH variable speed compressors include the addition of an
oil injection solenoid valve 2QM18 to provide supplemental
oil flow from an internal gear pump to the scroll thrust
bearing surface. The solenoid is de-energized at low
compressor speeds to allow supplemental oil flow and
ensure thrust surface lubrication. The solenoid is energized
at high compressor speeds to stop supplemental
lubrication. This prevents excessive oil circulation to the
system. The solenoid is controlled by the inverter and
switches at 3300 RPM for the VZH117, and 2700 RPM for
the VZH170.
The 115 VAC solenoid coil operation can be checked on
one of the solenoid leads with a clamp on amp meter.
Above 3300 RPM (VZH117) /2700 RPM (VZH170), the
amp meter should read about 0.5 amps to indicate
supplemental flow has been stopped.
Figure 118. Oil injection solenoid valve
Table 76. Oil charge per compressor
Compressor
Pints
CSHN374/CSHL346 15.2
CSHN176-315, CSHL169-285, and
VZH170
14.2
Table 77. Torque requirements for rotolock fittings
CSHN*/CSHL* and VZH170 100 +/- 10 ft-lbs
Note: Always replace gasket when reassembling oil
equalizer lines.
Service and Maintenance
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