Chapter 4 Compressor and Package Unit Operation
UD-series Screw Compressor
4.3 When Stopping the Compressor for a Long Time
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4.3
When Stopping the Compressor for a Long Time
Before stopping the compressor for a long time, make sure to perform the following steps.
Turn off the motor main power.
Turn off the oil heater power and the control power.
Close the suction stop valve and discharge stop valve.
If an economizer and/or liquid injection is (are) used, close the (each) stop valve(s) located at
the compressor inlet.
If the operation stop period is 1 month or longer, perform the following checks every month.
Operate the oil pump for 10 seconds per week.
After that, rotate the compressor shaft (10 rotations or more).
Measure the system pressure once per month.
Check for refrigerant leak once per month.
When restarting the compressor after an operation stop period of 1 year or longer, check the system for
refrigerant leak and analyze the lubricating oil. If it is found as a result of the analysis that the control
criteria given in Section 4.3.1 Tables 4-3 to 4-5 are not satisfied, the oil must be replaced.
Also check the motor insulation resistance.
Supply power to the oil heater at least 1 day before operation start. Before starting the operation,
confirm that the refrigerant is not condensed in the package by checking the package temperature and
pressure.
