5) Compressor discharge temperature
6) Motor winding temperature
7) Number of compressor starts
8) Control point settings
9) Discrete output status of various devices
10) Variable frequency drive status
11) Optional spare input channels
12) Line current and voltage for each phase
13) Frequency, kW, kWhr, demand kW
g. Schedule Function:
The chiller controls shall be configurable for manual or automatic start-up and shutdown. In automatic operation mode, the controls shall be capable of automatically starting and stopping the chiller according to a stored user programmable occupancy schedule. The controls shall include built-in provisions for accepting:
1) A minimum of two 365-day occupancy schedules.
2) Minimum of 8 separate occupied/unoccupied periods per day
3) Daylight savings start/end
4) 18 user-defined holidays
5) Means of configuring an occupancy timed override
6) Chiller start-up and shutdown via remote contact closure
h. Service Function:
The controls shall provide a password protected service function which allows authorized individuals to view an alarm history file which shall contain the last 25 alarm/alert messages with time and date stamp. These messages shall be displayed in text form, not codes.
i. Network Window Function:
Each chiller control panel shall be capable of viewing multiple point values and statuses from other like controls connected on a common network, including controller maintenance data. The operator shall be able to alter the remote controller’s set points or time schedule and to force point values or statuses for those points that are operator forcible. The control panel shall also have access to the alarm history file of all like controllers connected on the network.
j. Pump Control:
Upon request to start the compressor, the control system shall start the chilled and condenser water pumps and shall verify that flows have been established.
k. Ramp Loading:
A user-configurable ramp loading rate, effective during the chilled water temperature pulldown period, shall prevent a rapid increase in compressor power consumption. The controls shall allow configuration of the ramp loading rate in either degrees per minute of chilled water temperature pulldown or percent motor amps per minute. During the ramp loading period, a message shall be displayed informing the operator that the chiller is operating in ramp loading mode.
l. Chilled Water Reset:
The control center shall allow reset of the chilled water temperature set point based on any one of the following criteria:
1) Chilled water reset based on an external 4 to 20 mA signal.
2) Chilled water reset based on a remote temperature sensor (such as outdoor air).
3) Chilled water reset based on water temperature rise across the evaporator.
m. Demand Limit:
The control center shall limit amp draw of the compressor to the rated load amps or to a lower value based on one of the following criteria:
1) Demand limit based on a user input ranging from 40% to 100% of compressor rated load amps
2) Demand limit based on external 4 to 20 mA signal.