Chilled Water Recycle Mode - Carrier 17/19EX Start-Up, Operation And Maintenance Instructions Manual

When the SOFT STOP AMPS THRESHOLD is being applied, a status message
''SHUTDOWN IN PROGRESS, COMPRESSOR UNLOADING'' is shown.

Chilled Water Recycle Mode

The machine may cycle off and wait until the load increases to restart again when the
compressor is running in a lightly loaded condition. This cycling of the chiller is normal and is
known as recycle. A recycle shutdown is initiated when any of the following conditions are true:
• when in LCW control, the difference between the LEAVING CHILLED WATER tem-
perature and ENTERING CHILLED WATER temperature is less than the RECYCLE
SHUTDOWN DELTA T (found in the SERVICE 1 table) and the LEAVING CHILLED
WATER TEMP is below the CONTROL POINT , and the CONTROL POINT has not
increased in the last 5 minutes
when ECW CONTROL OPTION is enabled, the difference between the ENTERING
•
CHILLED WATER temperature and the LEAVING CHILLED WATER temperature is
less than the RECYCLE SHUTDOWN DELTA T (found in the SERVICE 1 table) and
the ENTERING CHILLED WATER TEMPERATURE is below the CONTROL POINT ,
and the CONTROL POINT has not increased in the last 5 minutes
• when the LEAVING CHILLED WATER temperature is within 3° F (2° C) of the BRINE
REFRIG TRIPPOINT
When the machine is in RECYCLE mode, the chilled water pump relay remains energized so
that the chilled water temperature can be monitored for increasing load. The recycle control
uses RECYCLE RESTART DELTA T to check when the compressor should be restarted. This