Trane Centrifugal Water Chillers CVGF - Manual (Page 21)

Standard Protections
Short-Cycling Protection
This function mimics heat dissipation from a motor start using two setpoints:
Restart Inhibit Free Starts and Restart Inhibit Start-to-Start Timer. This allows the CVGF to
inhibit too many starts in a defi ned amount of time while still allowing for fast restarts. The
default for CVGF is 3 Free Starts and a 20 minute Start-to-Start Timer. The control panel
generates a warning when the chiller is inhibited from starting by this protection.
Restart Inhibit Free Starts
This setting will allow a maximum number of rapid restarts equal to its valve. If the number of
free starts is set to 1, this will allow only one start within the time period set by the Start-to-Start
Time setting. The next Start will be allowed only after the Start-to-Start timer has expired. If the
number of free starts is programmed to 3, the control will allow three starts in rapid succession,
but thereafter, it would hold off on a compressor start until the Start-to-Start timer expired.
Restart Inhibit Start-to-Start Time setting
This setting defi nes the shortest chiller cycle period possible after the free starts have been
used. If the number of free Starts is programmed to 1, and the Start-to-Start Time setting is
programmed to 10 minutes. the compressor will be allowed one start every 10 minutes The
Start-to-Start time is the time from when the motor was directed to energize to when the next
prestart is issued.
21
Controls
CTV-PRC001-E4