Carrier 17/19EX - Manual (Page 76)

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 ON-
TIME. 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
register up to 32,767 hours before it rolls over to zero.