Damper Vapor Source; Demand Limit - Carrier SmartVu Control Manual

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:
Condition
Chiller initially Power ON
Compressor shutdown
During Damper Valve Act Delay
Economizer Pressure > Evaporator Pressure
+ Damper Valve Open DB
Economizer Pressure < Evaporator Pressure
+ Damper Valve Close DB
Otherwise
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 f low 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
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.
SRDC-UG-2-14-000
19 Series Carrier®
–
TM
SmartVu
Controls IOM
Economizer Damper Valve Status
Fully Close
Fully Close
Fully Close
Open
Close
Keep the current position
Economizer Damper Control - 1
TM
controls provide a f eature for limiting AVERAGE LOAD CURRENT or
REVISION DATE
2.3 Dec 4, 2020
PAGE
78 OF 168
78