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Service Information Letters / Bulletins
SI0019 - SOFTWARE ENHANCEMENTS EFFECTIVE MARCH 2002 (CONT'D)
•
Rate Limit Close Setpoint – Now programmable over the range of 5% to 50%. Previously, it was 10% to
50%.
•
The duration of the open or close pulse applied to the Valve Actuator is now independent of the selected
Period Setpoint. It is now a fi xed percentage of 3.5 seconds. Previously, it was a percentage of the Pe-
riod Setpoint. Therefore, longer Periods would produce longer output pulses for the same error, result-
ing in unstable op er a tion under certain conditions.
Compressor Motor Variable Speed Drive
•
The conditions to produce the "Harmonic Filter – Logic Board or Communications" Cycling shutdown
must now be present for 10 communication cycles before a shutdown is performed.
•
If either the 50% or 30% Leaving Chilled Liquid Temperature SENSITIVITY Setpoint is selected,
Pre-rotation Vane movement is further reduced when the chiller is operating at low load. When the Vane
position is less than 25% and Leaving Chilled Liquid Temperature is within + 2.5 ºF of Setpoint, the
maximum Vane pulse is limited to 3.5 seconds at 25% position and 0.9 seconds at 0% position. Vane
positions in between have linearly scaled maximums.
•
In previous Flash Memory Card versions, the SET FREQUENCY Setpoint feature on the VSD TUN-
ING Screen did not correctly set the desired frequency in 50Hz applications. This is corrected in this
version.
•
Harmonic Filter Currents are now correctly displayed at maximum values.
History
Chiller Run Time is now included on History Details display and print.
Hot Gas Bypass
The Hot Gas Valve position is now animated on the HOT GAS BYPASS Screen.
172
FORM 160.54-M1(503)
YORK INTERNATIONAL
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