JD COOLING | Top Tips
The following items are possible and common causes for compressor failures, which need to be identified and rectified before and during the commissioning of new / rebuild compressors.
1. Dirty Condensers:
Check that airways are clear, which may require jet washing or blown through with nitrogen, as any reduction in air movement will increase head pressure, which in turn causes premature stress to the plant and poor performance.
2. Dirty Evaporators:
Check airways are fully clear, which may require jet washing, as blocked evaporators will potentially lead to liquid return to the compressor / pack, which in turn, will cause mechanical damage or worst case, a full failure to the compressor.
3. Iced-Up Evaporators:
Check airways are fully clear of ice. Check defrost heaters and controls to ensure the evaporator heaters are functioning as design. A blocked evaporator will potentially lead to liquid returning to the compressor / pack, which could lead to mechanical damage or worst case, a full failure to the compressor.
4. Incorrect Pressure Control:
Erratic pressure control with the incorrect settings for the condenser fans will lead to the plant being inefficient, causing high discharge pressures, which in turn causes premature stress to the compressor. Incorrect condenser fan control can also cause over condensing, which causes lower pressure across the system and the potential to produce liquid migration to the compressor plant.
5. Incorrect Refrigerant Charge:
A prolonged lack of refrigerant within the system will minimise sufficient suction gas to return to the compressor to cool the compressor windings, therefore decreasing the life expectancy of the windings.
6. Incorrect Expansion Valve Control Settings:
The correct setting and actual checking of the superheat for any system is vital to ensure adequate refrigerant and temperature is entering / leaving the evaporator, which in turn will ensure the compressor has sufficient suction gas to cool the windings and minimise liquid return to the compressor sump.
7. Worn Contactors:
Worn contact phases on contactors could lead to single phasing of the electrical supplies to the compressor, or worst case a complete electrical failure – resulting in a possible motor failure.
8. Loose Wiring / Terminals:
Loose wiring or terminals could lead to single phasing of the electrical supplies to the compressor, or worst case a complete electrical failure – resulting in a possible motor failure.
9. Loose Compressor Support Fixings:
Loose fixings or support components of the compressor feet could lead to a mechanical failure if regular checks aren’t carried out to ensure the compressor is sufficiently in position.
10. Compressor Sump or Strap on Heaters:
During the winter months or long periods when the compressor plants are idle, it’s very important to make sure the sump heater(s) are working to maintain the oil temperature and to prevent any liquid migrating to the compressor sump. A compressor being off for a period of time or one that has been replaced with new, the heater needs to be switched to allow the oil to be heated to the manufactures guide to prevent mechanical failure during the start-up.
Please note:
Consider investing in a bespoke JD Cooling preventative maintenance package, which will reduce the number of untimely breakdowns, caused by compressor electrical / mechanical issues.
