78
If this kind of control valve is not equipped in the chiller, this function shall be bypassed.And the
economizer pressure shall display the minimum value of hardcoded.
When the chiller is initially powered ON, the damper valve will be commanded to close. When
compressor shuts down, the damper valve will be commanded to close.
The damper valve shall be acted based on the following table:
Economizer Damper Control - 1
If DMP_ACT is Fail, then control system should declare an alert 154.
If the damper valve has been command to open for a continuous 5 minutes, and the Damper Valve Full
Opened is still not TRUE, then control system should declare an alert 154.
If the damper valve has been command to close for a continuous 5 minutes, and the Damper Valve Full
Closed is still not TRUE, then control system should declare an alert 154.
5.13. Damper Vapor Source
For 19XRC/E/F improvement unit, there is vapor source damper which is controlled by a NC(normal
closed when valve coil is deenergized) solenoid valve and the pressure difference between damper cap
and flow passage.
The SV is closed when chiller is not running, and keep closed until a delay period after chiller starts
up(delay timer vssv_dly is configurable in CONF_OPT table). And after this timer is timeout, the SV
should be energized.
5.14. Demand Limit
The 19 Series Carrier® SmartVu
TM
controls provide a feature for limiting AVERAGE LOAD CURRENT or
Motor KILOWATTS by limiting capacity via guide vane control/VFD control. The limit applied is called
ACTIVE DEMAND LIMIT, which is equal to a BASE DEMAND LIMIT value (set in the SETPOINT
Screen, default value 100%), or be determined by AUTO DEMAND LIMIT INPUT (an optional 4-20 mA
input, described below). ACTIVE DEMAND LIMIT may also be forced to be different from BASE
DEMAND LIMIT by manually overriding the value (forcing) writing a value via a CCN network device.
If the DEMAND LIMIT SOURCE exceeds the ACTIVE DEMAND LIMIT by 5% or less, capacity will be
inhibited. If the DEMAND LIMIT SOURCE exceeds the ACTIVE DEMAND LIMIT by more than 5%,
capacity will be decreased.
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