York YR manual Display Only

OptiView Control Center (continued)

FORM 160.81-EG1

tacts include a Remote Mode Ready To Start, a Cy- cling Shutdown, a Safety Shutdown and a chiller Run Contact. Pressure transducers sense system pressures and thermistors sense system temperatures. The out- put of each transducer is a DC voltage that is analo- gous to the pressure input. The output of each ther- mistor is a DC voltage that is analogous to the tem- perature it is sensing.

Setpoints can be changed from a remote location via 0-10VDC, 4-20mA, contact closures or through serial communications. The adjustable remote reset range [up to 20°F (11.1°C)] provides flexible, efficient use of re- mote signal depending on reset needs. Serial data inter- face to the YORK ISN Building Automation System (BAS) is through the General Protocol Interface Card (GPIC), which can be mounted inside the Control Center.

This printed circuit board requests the required data from the Micro Board and makes it available for the YORK ISN network. This optional board is available through the YORK BAS group. The operating program is stored in non-volatile memory (EPROM) to eliminate chiller failure due to AC power failure/battery discharge. Pro- grammed setpoints are retained in lithium battery- backed RTC memory for 11 years minimum.

Smart Freeze Point Protection can operate the chiller as low as 36°F (2.22°C) leaving chilled water tempera- ture, without nuisance trips on Low Water Temperature. The sophisticated program and sensor monitors the chiller water temperature to prevent freeze-up. Each programmable point has a pop-up screen with the al- lowable ranges, so the chiller cannot be programmed to operate outside of its design limits.

Thermal ice storage systems are based on the concept of using off-peak, lower cost electricity to build ice for handling the cooling load during peak hours. The most efficient way to build ice is to maximize chiller load and minimize run time. Standard chiller control systems are not designed for this operating mode. In a typical appli- cation, chillers will load and unload to maintain a leaving chilled liquid setpoint. When the YORK YR chiller oper- ates in the thermal storage control mode, the unit will remain at 100% load until the setpoint shutdown tem- perature is reached. To add greater operating flexibility and eliminate unnecessary chiller cycling, two different Low Water (Liquid) Temperature Restart Thresholds can be programmed, one for the ice mode and one for the standard cooling mode. This control enhancement is stan- dard on all YR chillers. The chiller can also be left in the standard control mode for temperatures ranging between 20 and 70°F (-6.7 and 21.1°C), for applications involving a process or comfort cooling duty that requires leaving chilled liquid temperature setpoint control.

When power is applied to the chiller, the HOME screen is displayed. This screen displays a visual representation of the chiller and a collection of data detailing important op- erations and parameters. When the chiller is running, the flow of chilled liquid is animated by the alternating shades of color moving in and out of the pipe nozzles. The pri- mary values that need to be monitored and controlled are shown on this screen. They are as follows:

Display Only:

•Chilled Liquid Temperature – Leaving

•Chilled Liquid Temperature – Return

•Condenser Liquid Temperature – Return

•Condenser Liquid Temperature – Leaving

•Motor Run (LED)

•% Full-load Amps

•Operating Hours

With the “soft” keys the operator is only one touch away from the 8 main screens that allow access to the major information and components of the chiller. The 8 screens are the SYSTEM, EVAPORATOR, CONDENSER, COM- PRESSOR, OIL SUMP, MOTOR, SETPOINTS, and the HISTORY. Also on the Home Screen is the ability to Log IN, Log OUT and Print. Log In and Log Out is the means by which different security levels are accessed.

The SYSTEM screen gives a general overview of com- mon chiller parameters for both shells. This is an end view of the chiller with a 3-D cutaway of both the shells. The following can be viewed from this screen:

Display Only:

•Discharge Temperature

•Chilled Liquid Temperature – Leaving

•Chilled Liquid Temperature – Return

•Chilled Liquid Temperature – Setpoint

•Evaporator Pressure

•Evaporator Saturation Temperature

•Condenser Liquid Temperature – Leaving

•Condenser Liquid Temperature – Return

•Condenser Pressure

•Condenser Saturation Temperature

•Oil Temperature

•Differential Oil Pressure

•% Full-load Amps

•Current Limit

•Slide Valve Position

6 YORK INTERNATIONAL