Scroll Compressor Wear Calculation CGAM

Lab testing has shown that scroll compressor life can be prolonged by minimizing short cycling of the compressors.

In a tandem (or trio) compressor arrangement, when one of the two or three compressors on that circuit never come on, lubrication of internal components decreases as compared to compressors which regularly come on.

CGAM chillers have the ability to allow any compressor on either circuit to be the first compressor on. There is also an ability to allow only the lead compressor (Compressor A) to be the first compressor on when there is a call for cooling. Run time of the compressors or run time on a circuit is referred to as “Wear”.

There is a wear number for a compressor:

• Compressor Wear = Number of Starts + Number of Hours

There is a wear number for a circuit:

• Circuit Wear = (Compressor A Wear + Compressor B Wear) / 2
  • Note: For 3 compressor circuit Compressor (A + B + C) / 3

In order to balance the compressor wear between compressors as well as get all compressors to come on, it is recommended that Circuit Staging and Compressor Staging both be set up for “Balanced Starts and Hours”. These settings can be found when connecting to the chiller using Kestrelview (or Techview) and going into Unit View. The settings can be found in the Capacity Control Tab.

Below is a screen shot of where the setting can be changed within Unit View when connected with Kestrelview (or Techview)

Additional Note:     HUB solution DOC-107808 can be referred to to set chiller controls to help with short cycling on CGAM Chillers.