Demand Limiting; Power Failure Restart Delay; Alarms - Carrier WSHP Open v3 Integration Manual

Sequence of Operation

Demand limiting

The WSHP Open can accept 3 levels of demand limit from the BACnet network. In response to a demand limit, the
unit decreases its heating setpoint and increases its cooling setpoint to widen the range, in order to immediately
lower the electrical demand. You can configure the temperature adjustment for both heating and cooling and for
each demand level. You can also set the response to a particular demand level to 0.

Power failure restart delay

The control provides a delay when recovering from a power failure, a shutdown mode, or when transitioning from
unoccupied to occupied mode, in order to prevent excessive demand when many units start simultaneously. Each
unit can be configured for a unique delay between 0 and 600 seconds. The factory-programmed default delay is
60 seconds.

Alarms

Fire/Smoke Detector Alarm – The control monitors the voltage input to J1-9 to detect if a smoke detector or fire
detector NC contact has opened, indicating an alarm condition. The control verifies the presence of 24 Vac on this
input. If the input opens at any time, an alarm is generated after 3 seconds and the equipment (fan, compressor,
aux heat, and damper) immediately shuts down.
Space Temperature Alarms – The control provides the ability to generate an alarm when the space temperature
exceeds the alarm setpoint. A separate occupied hysteresis and fixed unoccupied high and low alarm setpoints
are provided. The control provides a 5-minute alarm delay during unoccupied periods. During occupied periods,
the control uses the occupied temperature setpoint and applies the hysteresis value to determine the alarm
setpoints. When occupancy transitions from unoccupied to occupied or the occupied temperature setpoints are
changed, causing an alarm condition to occur, the control automatically calculates an alarm delay (equivalent to
the configured delay time in minutes/ °F, multiplied by the temperature error, + 15 minutes). This prevents
nuisance alarms when an occupancy change occurs and allows time for the unit to correct an alarming
temperature condition.
Source Water Temperature Alarm – The control has 4 configurable alarm limits for source water temperature.
The control verifies that the water temperature is within operating range (between high and low limits) for the
specific operating mode (heating or cooling) before energizing the compressor. Once the compressor is started,
the source water temperature is further monitored to verify that it is within limits to insure sufficient water is
flowing through the coil. If the leaving water temperature rises above or falls below the appropriate limits, and
lasts for more than 15 seconds, an alarm is generated and the compressor shuts down.
Supply Air Temperature Alarm – The control has 2 configurable alarm limits for supply air temperature. The
control verifies that the supply air temperature is within operating range (between high and low limits) when the
compressor or auxiliary heat is operating. If the air temperature rises above or falls below the appropriate limits,
and this lasts for more than 5 minutes, an alarm is generated.
High Condensate/Overflow Alarm – The control monitors a discrete input to determine the state of a condensate
level switch. You can configure the input to alarm on either an open or closed switch condition. If this input is in an
alarm state, the control starts a timer, and after the timer exceeds a configurable Condensate Overflow Alarm
Delay limit (10 second default), the control generates an alarm and the unit disables the compressor and fan
outputs.
WSHP Open v3
Integration Guide
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