09: Squeaking Of Mechanical Seal; 10: Capacity Control Position Is Indicated Incorrectly - mycom 3225**C Series Instruction Manual

08: Leak from mechanical seal (continued)
Direct cause
Poor contact of sliding
surfaces

09: Squeaking of mechanical seal

Direct cause
During initial period after
exchange for new
mechanical seal, squeaks
may be heard from sliding
surfaces until they fit
together.

10: Capacity control position is indicated incorrectly

Direct cause
Inaccurate reading of
compressor indicator
gauge.
Inaccurate reading of
capacity control indicator
on the control panel.
Compound 2-stage Screw Compressor 3225**C
Root cause
Foreign matter attached to
sliding surfaces, due to
contaminated lubricating oil.
Faulty assembly of parts
Human error
Root cause
As the sliding surfaces are very
hard and dense, they need
time to fit together.
Root cause
Screw for securing indicator
needle is loose.
Indicator's bevel gears are
worn.
The cam groove of
compressor's indicator cam is
worn.
The guide pin of the
compressor push rod is worn.
Failure of potentiometer
Improper zero span adjustment
of E/E positioner
6-7
2202MYJE-MY-C8-N_2018.02.
Chapter 6 Troubleshooting
Action
Replace the whole quantity of
lubricating oil.
Install bypass filter to oil supply line.
Disassemble, replace parts and
reassemble.
Use assembly check sheet to ensure
confirmation.
Action
Squeaking itself does not cause leak
from seal or deterioration in sealing
function.
Normally, squeaking is heard for
several dozens of hours, however, it
may last longer in rare cases.
→In this case, contact our service
center.
Action
Manually operate the compressor's
capacity control to indicate 0%
position, and tighten the screw again.
If deteriorated over time, replace.
If the wear is caused by excessive
vibration of the compressor, take
measures to reduce vibration and
then replace the bevel gears.
Often caused by continued operation
with load on a certain point.
→Replace the indicator cam.
* The currently shipped indicator cam
has its grooved portion
strengthened.
Currently, this pin is also improved in
resistivity against wear. If the indicator
cam is replaced with the improved
version, replace the pin with the
countermeasure part.
If the part is deteriorated over time or
loaded at a certain point during
operation for a long time, replace it.
If the wear is caused by excessive
vibration of the compressor, take
measures to reduce vibration and
then replace the potentiometer.
Readjust.