Carrier PC211 Refrigerator User Manual


 
vane response to chilled water temperature below deadband plus control point. It can be
adjusted on the LID from a setting of 2 to 10, and the default setting is 6.0. Increasing either of
these settings will cause the vanes to respond slower than a lower setting.
The
PROPORTIONAL ECW GAIN
can be adjusted at the LID display from a setting of 1.0 to
3.0, with a default setting of 2.0. Increase this setting to increase guide vane response to a
change in entering chilled water temperature. The proportional bands and gain may be viewed/
modified on the Equipment Service3 table.
Demand Limiting
The PIC will respond to the
ACTIVE DEMAND LIMIT
set point by limiting the opening of the
guide vanes. It will compare the set point to either
COMPRESSOR MOTOR LOAD
or
COMPRESSOR MOTOR CURRENT
(percentage), depending on how the control is configured
for the
DEMAND LIMIT SOURCE
which is accessed on the SERVICE1 table. The default
setting is current limiting.
Machine Timers
The PIC maintains 2 runtime clocks, known as
COMPRESSOR ONTIME
and
SERVICE
ONTIME. COMPRESSOR ONTIME
indicates the total lifetime compressor run hours. This timer
can register up to 500,000 hours before the clock turns back to zero. The
SERVICE ONTIME
is
a resettable timer that can be used to indicate the hours since the last service visit or any other
reason. The time can be changed through the LID to whatever value is desired. This timer can