Sequence of Operation
OAU-SVX006E-EN
87
Sensor Source Failures
The following diagnostics are displayed when the
respective sensor reading is outside of the expected
range, indicating that the sensor may be faulty. Refer to the
points list for expected ranges of each input.
In some cases, a BAS point is In Service, and will take
priority over a hardwired input. If the point was
inadvertently put In Service, and the BAS is either not
writing a value or the value is outside of the expected
range, then the program will first attempt to fall back to a
hardwired input before displaying a source failure
diagnostic.
•
Diagnostic: Dehumidification Temperature Sensor
Source Failure*
•
Diagnostic: Discharge Air Humidity Source Failure
•
Diagnostic: Discharge Air Temperature Source Failure
•
Diagnostic: Duct Static Pressure Source Failure
•
Diagnostic: Outdoor Air Flow Sensor Source Failure
•
Diagnostic: Outdoor Air Humidity Source Failure
•
Diagnostic: Outdoor Air Temperature Source Failure
•
Diagnostic: Return Duct/Space Pressure Source Failure
•
Diagnostic: Space CO2 Source Failure
•
Diagnostic: Space Humidity Source Failure
•
Diagnostic: Space Temperature Source Failure
*The Dehumidification Temperature Sensor is the
Indoor
Coil Leaving Air Temperature Local
on all cabinets except
for the OANG (OAN Rev. 6). For the OANG cabinet, the
sensor is the
Discharge Air Humidity Local
.
Economizer Fault Detection and
Diagnostics
Not Economizing When It Should be Economizing
is
displayed when unit is in
Economizer Mode
and the
Outdoor Air Damper Position Status
Local is 20% below
the
Outdoor Air Damper Position Command
for 20-
minutes.
Damper Not Modulating
is displayed if the
Outdoor Air
Damper Position Status Local
is 20% below the
Outdoor
Air Damper Position Command
for 20-minutes.
Mixed Air Low Limit Active
is displayed when the unit
is in
Economizer Mode
and the unit is limiting the
Outdoor
Air Damper Position Command
to prevent the mixed air
temperature from falling below 35°F. Units equipped with
Class 1A dampers will use a sensor,
Mixed Air
Temperature Local
. Otherwise, the unit will estimate the
mixed air temperature using
Outdoor Air Temperature
Active, Return Air Temperature Local
, and the
Outdoor Air
Damper Position Command.
