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Table 4 — RTU Open Alarms
POINT NAME
BACnet Object
NAME
ACTION TAKEN BY
CONTROL
RESET METHOD PROBABLE CAUSE
Safety Chain safety_alarm Immediate Shutdown Automatic Over load Indoor Fan or Electric Heater
overheat
Fire Shutdown fire_alarm Immediate Shutdown Automatic Smoke detected by smoke detector or
configuration incorrect
Gas Valve igc_alarm Immediately operate fan at
highest speed
Automatic Gas valve stuck open after heating
cycle, causing heat to continue to
operate.
Supply Fan sfan_fail_alarm Immediately disable
Operation
Automatic Tripped Circuit Breaker, Broken belt,
Bad indoor fan motor, Configuration
incorrect, Bad fan status switch.
Supply Fan in Hand sfan_hand_alarm Ramp down Operations Automatic Bad Fan Status Switch, Configuration
incorrect.
Compressor Status comp_alarm Alert Generated Automatic Compressor would not start
Space Temp Sensor spt_fail Ramp down Operations Automatic Bad sensor, bad wiring, failure to
receive Network or Linkage Space
Temp value, or sensor configured
incorrectly.
ZS Sensor zst_sensor_fail Alert Generated Automatic This alarm indicates a communication
failure of a connected ZS sensor that
previously had been actively
communicating.
ZS Configuration zs_config_fail Alert Generated Automatic This alarm indicates that at least one
ZS sensor is configured in the Sensor
Binder properties and is not actually
communicating.
Supply Air Temp Sensor loc_sat_sensor_fail Ramp down Operations Automatic Faulty, shorted, or open thermistor
caused by wiring error or loose
connection.
Local OAT Sensor ioc_oat_sensor_fail May cause Economizer and Low
ambient DX cooling lockout to be
disabled
Automatic Faulty, shorted, or open thermistor
caused by wiring error or loose
connection.
Outdoor Air Temp Sensor oat_fail Economizer and Low ambient DX
cooling lockout disabled.
Automatic Failure to receive valid local or network
value for Outdoor Air Temperature
Space Relative
Humidity Sensor
sprh_sensor_fail Dehumidification disabled Automatic Sensor reading is out of range. Bad
sensor, bad wiring, failure to receive
Network or Linkage RH value, or
sensor configured incorrectly.
Indoor Air Quality Sensor iaq_sensor_fail No IAQ Operation Automatic Sensor reading is out of range. Bad
sensor, bad wiring, failure to receive
Network or Linkage RH value, or
sensor configured incorrectly.
Outdoor Air Quality
Sensor
oaq_fail Control uses default OAQ value of
400 ppm.
Automatic Sensor reading is out of range. Bad
sensor, bad wiring, failure to receive
Network value, or sensor configured
incorrectly.
Economizer Operation econ_opr Alert Generated Automatic This alarm is active whenever an
economizer fault is detected as
required by the California Title 24
Economizer FDD logic.
Economizer fault conditions include;
Failed to Fully Open, Failed to Open,
Failed to Close, and Stuck Open.
Space Temperature spt_alrm_status Alert Generated Automatic Space Temperature value is less than
the low limit value or greater than the
high limit value
Supply Air Temperature sat_alarm Alert Generated Automatic SAT is greater than the high limit value
or less than the low limit value for more
than 5 minutes
Setpoint Slider slidepot_alarm Set Offset to zero Automatic STO sensor is open for more than 5
seconds
Switch Configuration di_cfg_alarm Disable only wrong switch
functions
Configure correctly More than one discrete input is
configured to provide the same
function.
Analog Input
Configuration
ai_cfg_alarm Disable 4 selectable analog inputs Configure correctly More than one analog input is
configured to provide the same
function.
Space Relative Humidity sprh_hi_alarm Alert Generated Automatic Indoor RH is greater than the high limit
value or less than the low limit value for
more then 15 minutes
Indoor Air Quality iaq_alarm Alert Generated Automatic CO
2
ppm reading is above the
configuration for 1 minute
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