108
SCXF-SVX01Q-EN
Category Diagnostic
Controls
Reaction
These unit functions occur:
• Low Ambient Compressor Lockout Disables
• O/A damper drives to minimum position
• On VAV units with S/A temp. reset type selected as O/A temp. reset, the reset type reverts to “none” for the duration of the
failure
Reset
Required
(PAR) an automatic reset occurs after the O/A temperature input returns to its allowable range. To prevent rapid cycling of the
diagnostic, there is a 10 second delay before the automatic reset.
Occupied Zone Heat Setpoint Failure
Problem
The occupied zone heat setpoint input is out of range.
Reason for
Diagnostic
The input designated as occupied zone heating setpoint source is out of range for the outside air temperature input on the RTM
(temp. < 45°F or temp > 94°F).
Reaction
The active occupied zone heating setpoint reverts to the default value.
Reset
Required
(PAR) an automatic reset occurs after the occupied zone heating setpoint input returns to its allowable range for 10 continuous
seconds, or after a different occupied zone heating setpoint selection source is user-defined.
R
Return Air Humidity Sensor Failure
Problem
On units with both airside economizer and comparative enthalpy installed, the return air humidity sensor input is out of range.
Check
Check field/unit wiring between the sensor and ECEM.
Reason for
Diagnostic
The unit is reading a signal that is out of range for the return air humidity sensor (humidity < 5% or humidity > 100%).
Reaction
The economizer enable r.e. enthalpy function reverts to reference enthalpy changeover (“Level 2”) control.
Reset
Required
(PMR) An automatic reset occurs after the RA humidity input returns to its allowable range continuously for 10 seconds.
Return Air Temperature Sensor Failure
Problem
On units with the comparative enthalpy option, the return air temperature sensor input is out of range.
Check
Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between the
sensor and ECEM.
Reason for
Diagnostic
The unit is reading a signal that is out of range for the return air humidity sensor (temp < -55°F or temp > 209°F).
Reaction
The economizer enable r.e. enthalpy function reverts to reference enthalpy changeover (“Level 2”) control.
Reset
Required
(PAR) An automatic reset occurs after the RA temp input returns to its allowable range continuously for 10 seconds.
RTM Auxiliary Temperature Sensor Failure
Problem
The RTM auxiliary temperature sensor data is out of range.
Check
Sensor resistance should be between 830 ohms (200°F)and 345.7 ohms (-40°F). If so, check field/unit wiring between sensor
and RTM.
Reason for
Diagnostic
At least one enabled unit function has the RTM auxiliary temperature input designated as its sensor, and the unit is reading a
signal that is out of range for this input (temp. < -55°F or temp > 209°F).
Controls
Reaction
The functions with the RTM auxiliary temperature input designated as their sensor are disabled.
Reset
Required
(PAR) an automatic reset occurs after the designated zone temperature signal returns to its allowable range. To prevent rapid
cycling of the diagnostic, there is a 10 second delay before the automatic reset.
RTM Data Storage Error
Problem There was a data transmission error.
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