Chilled water recycle mode – Carrier 17/19EX User Manual
Page 122
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