Alarms - Carrier VVT Zone Installation And Startup Manual

Alarms

Space Temp Sensor Alarm – The VVT Zone Controller monitors each space temperature sensor and the
network input for space temperature. If no valid space temperature value is available, the controller
generates an alarm and disables all local heating or cooling. The controller modulates the damper to the
minimum heat, minimum cool, or ventilation position based on the air source mode. Normal operation
resumes when the controller detects a valid sensor value.
Space Temperature Alarm – The controller generates an alarm if the space temperature exceeds the alarm
setpoint. The occupied alarm setpoint is the configurable Occupied Alarm Hysteresis (5°F default) subtracted
from and added to the configured occupied heat and cool setpoints. The configurable unoccupied high and
low alarm setpoints have a fixed 10 minute alarm delay. When a transition from unoccupied to occupied
occurs or the occupied temperature setpoints are changed, causing an alarm condition, the controller
automatically calculates an alarm delay of 10 minutes for each degree of change. The delay prevents
unnecessary alarms and gives the zone time to correct the alarm condition. The alarm returns to normal
when the space temperature goes between the current mode's setpoints.
Supply Air Temperature Alarm – The controller generates an alarm if the SAT exceeds the configured High
SAT Alarm Limit (120°F default) or falls below the Low SAT Alarm Limit (45°F default) for more than 5
minutes. The hysteresis for return to normal is 1°F.
Space Relative Humidity Alarm – If a Space Relative Humidity (RH) sensor is installed, the controller
generates an alarm if the sensor's value exceeds the Occ High RH Alarm Limit (100% rh default) or the Unocc
High RH Alarm Limit (100% rh default). The controller provides a 30-minute alarm delay during unoccupied
periods. During occupied periods, the controller uses the Occ High RH Alarm Limit. When a transition from
unoccupied to occupied occurs or the occupied high alarm limit is lowered causing an alarm condition to
occur, the controller automatically calculates an alarm delay of 5 minutes per %RH multiplied by the amount
of the change. The delay prevents unnecessary alarms and gives the zone time to correct the alarm condition.
The hysteresis for return to normal is 3% RH.
Indoor Air Quality Alarm – If a CO sensor is installed, the controller generates an alarm during occupied
2
periods if the sensor's value exceeds the Occupied High CO2 Alarm Limit. When a transition from unoccupied
to occupied occurs, or if the occupied alarm limit is changed to a value that causes an alarm condition to
occur, the controller automatically calculates an alarm delay based on the error from setpoint (15 minutes
minimum, 4 hours maximum). The delay prevents unnecessary alarms and gives the zone time to correct the
alarm condition. To disable the IAQ alarm, set Occupied High CO2 Alarm Limit to 0. The default value is
1100ppm. The hysteresis for return to normal is 100ppm.
Filter Alarm – For series or parallel fan-powered terminals, the controller monitors the accumulated hours of
fan operation and generates an alarm when the Filter Runtime hours exceed the configured Filter Service
Alarm Timer limit. The default value is 0 hours which disables the alarm. The alarm can be reset by setting
Reset Filter Alarm to On or resetting the configured alarm limit to 0 hours.
Airside Linkage Alarm – The slave zone controller generates an alarm if it does not receive linkage
information for 5 minutes. If the controller is the VVT Master, it generates an alarm if it does not communicate
with its air source for 5 minutes. A return-to-normal is generated after successful Linkage communication
resumes.
VVT Zone Controller 45