Unit installation

Diagnostics
98 SCXF-SVX01K-EN
Return Air Temp 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).
UCM 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 Aux. Temp. 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).
UCM 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.
Check:This can be caused by an intermittent power loss.
Turn the unit off for 1-2 minutes, then back on again. If
diagnostic persists, then the RTM may need to be
replaced.
Reason for Diagnostic: An error occurred while the RTM
was writing data to its internal non-volitile memory
(EEPROM).
UCM Reaction: An information only diagnostic will be
displayed at the human interface.
Reset Required: (INFO) A manual reset may be made at the
human interface, atTracer Summit, or by cycling power to
the RTM.
RTM Zone Sensor Failure
Problem:The RTM zone 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 sensor and RTM.
Reason for Diagnostic: At least one enabled unit function
has the RTM zone 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 > 150°F).
UCM Reaction:The functions with the RTM zone
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.
S
SCM Communication Failure
Problem:The RTM has lost communication with the SCM.
Check: Check field/unit wiring between the RTM and SCM.
Reason for Diagnostic:The RTM has lost communication
with the SCM.
UCM Reaction: A “lockout” request is sent to the
compressor staging control function.A failsafe function in
the SCM will cause all SCM outputs to be zeroed and
deenergized.
Reset Required: (PAR) An automatic reset occurs after
communication has been restored.
Space Static Press Setpt Failure
Problem:The active space static pressure setpoint is out of
range.
Check: Check setpoint value. Also, if space pressure
setpoint source is GBAS, but this setpoint has not been
assigned to any of the four analog inputs on GBAS, this
message will occur.
Reason for Diagnostic:The unit is reading a signal that is
out of range for the space static pressure setpoint (input <
0.03 iwc or input > 0.20 iwc).
UCM Reaction:The default space pressure setpoint will
become the active space pressure setpoint.
Reset Required: (PAR) An automatic reset occurs after the
designated space pressure setpoint source sends a signal
within range for 10 continuous seconds, or after a different
space pressure setpoint source is user-defined.
Supply Air Pressure Sensor Failure
Problem:The supply air pressure sensor voltage input is
out of range.
Check: Check field/unit wiring between the sensor and
RTM.
Reason for Diagnostic:The unit is reading a signal that is
out of range for the supply air pressure sensor voltage
input (input < 40mV or input > 4.75V)