Capacity Control Screen - York YD Mod D Operation Manual

Capacity control screen

Figure 21: Capacity control screen
This screen displays the pertinent parameters associated with capacity control in relation to Leaving
Chilled Liquid temperature, current and pressure overrides, and anti-surge control.
Table 48: Display only fields
Field/LED name
Evaporator pressure
[Evaporator pressure] override
threshold
Condenser pressure
[Condenser pressure] override
threshold
Motor current % FLA
[Motor current % FLA] override
threshold
Entering liquid - evaporator
Entering liquid - condenser
Leaving liquid - evaporator
Leaving liquid - condenser
Active LCHLT setpoint
62
Description
Displays the pressure in the evaporator.
Displays the evaporator pressure setpoint below which the low evaporator pressure
capacity control override takes effect.
Displays the pressure in the condenser.
Displays the condenser pressure setpoint above which the high condenser pressure
capacity control override takes effect.
Displays the percentage of maximum motor current delivered to the motor,
determined from the highest of the three phase Motor Currents/Maximum Motor
Current Limit.
Displays the active input current percent limit, which is the minimum of Local Input
Current Limit, Remote Input Current Limit, and Pulldown Current Limit or BAS (ISN)
current limit.
Displays the temperature of the chilled liquid as it enters the evaporator.
Displays the temperature of the condenser liquid entering the condenser.
Displays the temperature of the chilled liquid as it leaves the evaporator.
Displays the temperature of the liquid leaving the condenser.
Displays the active temperature setpoint to which the chiller is set to control liquid
leaving the evaporator. The Active Setpoint is a target to the Local, Remote or BAS
(ISN) LCHLT programmed setpoint, depending on the control source selected.
When the chiller is not running, the Active Setpoint is set to Entering Chilled Liquid
Temperature - LCHLT Setpoint Start Offset When the VSD starts, the Active LCHLT
Setpoint is ramped to the programmed LCHLT Setpoint at the programmable LCHLT
Setpoint Ramp Rate. When the chiller is running, performing capacity control, any
change to the programmed LCHLT setpoint results in a ramp from the old Active
Setpoint value to the new LCHLT setpoint value at the programmed LCHLT Setpoint
Ramp Rate.
Model YD Mod D with OptiView Control Center