16
Another effect which has been noted, especially in multi-
ple compressor systems, is the increased probability of
blown valve plate gaskets when excessive oil is in the
system. When the system is grossly overcharged (several
gallons too much), the oil levels in the compressor
sumps will only rise 1/2 to 3/4 level in the sightglass of
06E compressors. The remainder of the oil will be kept
in circulation or will accumulate somewhere in the sys-
tem. A likely point is in the suction manifold (depending
on the method of returning oil), and in the compressor
motor compartment. This is especially troublesome in an
idle compressor in a multiple compressor system that
has an opportunity to accumulate oil in the motor com-
partment; but excessive oil in the motor compartment at
start-up will not alone fail gaskets. Some liquid refriger-
ant must also be present which will bring enough oil
with it into the cylinders on a start-up to cause gasket
failures. These circumstances have apparently occurred
in a number of installations, and their relationship to
gasket failures has been well confirmed by test.
To check for excessive system oil charges in 06E com-
pressors, it is recommended that the oil levels of the
compressors in the system be brought down to approxi-
mately 1/4 of the sightglass. If the system is overcharged,
the oil levels will rise to a 1/2 sightglass level within a
short time (usually within an hour). Continue removing
oil until the oil level does not rise after removal. It is
also recommended that the oil levels be kept at this 1/4
level, or between the levels shown in Figure 8. This is
especially true if any compressors have experienced any
repeated gasket failures. To summarize the advantages of
keeping the oil at this level:
1. It ensure that excessive oil is not being lodged in the sys-
tem. This will eliminate gasket, valve, and running gear
failures.
2. The compressor, oil, and motor run cooler, approxi-
mately 20°F (11°C) or more in many cases.
As noted above, the oil level control in 06D compressors
is less critical than 06E models. Motor barrel equaliza-
tion is not required and oil level in the compressor
sightglass should be controlled between 1/4 to 3/4 of the
sightglass (See Figure 9). If the oil level in the sightglass
is less than one-quarter (1/4) up from the bottom of the
glass, this indicated a low oil level. If the oil level is up
more than three-quarters (3/4) from the bottom, this
indicates a high oil level. Again, the oil level should be
checked immediately after the compressor is shut down.
2.2 The Oil Pump
The 06D and 06E oil pump is a positive displacement
vane type that produces high volume oil flow at a low oil
pressure. The compressor utilizes an internal pressure
regulator valve to maintain oil pressure at a constant 12
to 36 psi (.83 to 2.5 bar) above suction pressure.
2.3 Recommended Oils
When additional oil or a complete oil change is
required, use only the listed Carlyle approved oils.
For CFC and HCFC refrigerants use:
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