Flooded type water cooled screw chiller (PCB Control)
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operation. It’s good for finding and forecasting the problem that may occur and taking measures in time.
For example, by analyzing the record of a whole month, you may find that the temperature difference of
condensing temperature and leaving cooling water temperature may become bigger. It means that the
cooling water is dirty or water hardn
ess is big, and it is scaling constantly. So it’s compulsory to perform
softening process or clean the tubes.
Note: Keeping the normal operation parameters of initial unit commissioning is very useful. It can be
used for comparative analysis to find out the trend of problem.
Scheduled maintenance
General
Take notice of the noise at any time by standing 1m from the unit. Watch the vibration amplitude at all
times to see whether it’s within permitted. Check the voltage of power supply whether it’s within ±10% of
rated voltage at any time.
Visual inspection
Keep the unit clean, if there’s rust, do scaling with iron brush and cover it with antirust paint. Pay
attention to the oil traces (sign of a refrigerant leak) and water traces on pipeline. Check the threaded
connection joints carefully, fasten any loose screw in time. Any time seeing the insulating material flakes
off, stick them with adhesive.
Compressor
For insulation resistance, check it yearly and it
should be over 5MΩ when measuring with ohmmeter of
DC 500V. When touching the shockproof rubber, it should be elastic, or it means the rubber gets ageing.
Every 3000 hours, make middle inspection of vibration and oil level; every 6000 hours, check the safety
device and protective device to guarantee the normal operation.
Important: The normal oil level is at the middle of sight glass. Adding lubricating oil if the oil level decline
obviously. Inspect the oil quality monthly
to see if there’s dirt or deterioration, otherwise, replace the oil
and filter core if necessary by specialized technicians. Make chemical analysis of the lubricating oil, if
emulsification phenomenon occurs, change the oil of same brand.
Heat exchangers
Adjust the water flow to keep the high/low pressure within normal range (high pressure 0.6~1.2MPa/low
pressure 0.1~0.4,If the temperature difference between leaving cooling water temperature and
refrigerant temperature in condenser is larger than 6 °C, it means the condenser is scaling and
cleanness work is in urgent need. When the chiller stops for a long time, water in heat exchangers and
pipe system should be drained thoroughly. For newly installed chiller, the filters in water system should
be cleaned after running for 24 hours and then clean the filters quarterly.
Valves and pressure controllers
▲ Safety valves
Inspect the integrity and performance of valves every year. The maintenance of safety valves should be
done by specialized technicians. Take apart the connecting pipe of safety valve, and check it to see
