Chapter 5 Maintenance and Inspection
UD-series Screw Compressor
5.2 Maintenance and Inspection List
5-3
5.2
Maintenance and Inspection List
5.2.1
Daily Management
For the purpose of daily maintenance, check the items listed in Table 5-1 "Daily Inspection Items" and
record the results.
These operation data should be recorded in an operating log book on a daily basis. This practice is
significantly effective and helpful in finding out any abnormal condition of the compressor and prevents
possible compressor failures.
In particular, it is important to confirm the absence of any abnormality between the temperature and
pressure correlations related to the refrigerant evaporation and condensation. It is possible to find any
abnormal condition in the compressor or the system quickly by monitoring the evaporation and
condensation temperature and pressure.
If any compressor/system failure or operating accident occurs, the operating log book will help the
cause to be clear and take appropriate measures promptly.
Table 5-1 Daily Inspection Items
Inspection item
Inspection details
Checkpoints and actions
C
om
pr
e
s
s
o
r
Operating hours
hr.
Total operating hours
Judgment of periodic maintenance
timing
Suction pressure
MPa
Difference from the set value of
evaporation temperature
equivalent pressure
Contamination in the evaporator
Temperature, flow rate, etc. of the
object to be cooled
Discharge pressure
MPa
Difference from cooling water
temperature equivalent
condensing pressure
Contamination on condenser
cooling pipes
Non-condensable gases mixed into
the system
Quantity, temperature, etc. of
cooling water
Oil supply pressure
MPa
Difference from discharge
pressure
Whether differential pressure is
decreasing
Operation with liquid flow-back
Whether compressor parts are
worn
Oil filter pressure
loss
MPa
Pressure difference between oil
filter inlet and outlet
Contamination of the lubricant
Clogged of oil filter
Suction temperature
°C
Whether within upper and lower
limits
Temperature, flow rate, etc. of the
object to be cooled
Degree of suction
superheat
°C
Whether degree of superheat is
proper
Adjust expansion valve
Insufficient refrigerant flow
Discharge
temperature
°C
Whether within upper limit
Non-condensable gases mixed into
the system
Oil supply temperature, insufficient
oil supply
Compressor failure
Oil supply
temperature
°C
Whether within upper and lower
limits
Contamination on cooling pipes of
oil cooler
Operation check of
Slide valve
%
Whether operation is normal
Damage to solenoid valve coil
Adjustability of manual
control(needle) valve for Solenoid
valve assembly
Leak from
mechanical seal
mL/h
Leak per hour
Damage to mechanical seal
assembly
Noise and vibration
-
Abnormal noise/vibration
Compressor failure
