York YD Mod D, Operation Manual, Page: 61 / 160

Table 45: Display only fields
Field/LED name Description
Lead VGD position Displays the position of the lead compressor Variable Geometry Diffuser.
Lag % Full Load Amps
Displays the motor current of the lag compressor as a percentage of the Full Load
Amps of that compressor motor.
Lag PRV position Displays the position of the lag compressor pre-rotation vanes position.
Lag VGD position Displays the position of the lag compressor Variable Geometry Diffuser.
Table 46: Programmable
Button Access level Description
Count window Operator
Allows the user to define the period of time (15 to 120 minutes; default 60) in which
the number of surge events are compared to the Count Limit threshold. Each time
a surge occurs, the Surge Window Count increments. If the Surge Window count is
less than or equal to the Count Limit, a close signal is applied to both compressor
#1 and #2 Pre-Rotation Vanes until compressor #1 motor current is within 20% of
compressor #2. While the vanes are closing, “Warning – Anti Surge- Excess Surge
Limit” is displayed until the motor currents are balanced with 20%, whereupon it
automatically clears. If the Surge Window Count exceeds the Count Limit, the lag
compressor is taken off line and “Warning – Anti Surge –Surge Limit Exceeded” is
displayed. This is displayed until manually reset with the Warning Reset Key.
Count limit Operator
Allows the user to define the maximum number of surge events (2 to 8; default 3)
that can occur within the programmed Count Window period of time before the lag
compressor is taken offline. Each time a surge occurs, the Surge Window Count is
incremented. If the Surge Window Count. If the number of surge events within the
Count window exceeds the Count Limit, the lag compressor is taken off line and
“Warning – Anti Surge – Surge Limit Exceeded” is displayed. This will be displayed until
manually cleared with the Warning Reset key.
Clear surge count Admin Allows user to reset dual compressor Total Surge Count to zero.
High head DP/P
limit
Service
Specifies the Delta P/P head condition [(Condenser pressure - Evaporator pressure) /
Evaporator pressure], above which the Lead compressor’s Pre-rotation Vanes will be
driven closed while the Lag compressor is starting. This avoids surging during high
head conditions.
Table 47: Navigation
Button Access level Description
Home View Returns to the Home screen.
Surge View Returns to the Main Surge screen.
61 Model YD Mod D with OptiView Control Center