©201
7
Nelson Heat Tracing Systems
www.nelsonheaters.com
GA2497 Rev.
5
CM-2201/CM-2202
Troubleshooting
9.4.1
High RTD A/ RTD B Temperature Reading
This warning/alarm appear when the temperature exceeds the
HIGH RTD WARNING/ALARM temperature setting.
CauseofWarning/Alarm:
• Warning/Alarm
temperature
setting
too
close
to
maintain
temperature
• Flow
of
hot
product
• Steaming out lines
• Incorrect tracer wiring
9.4.2
Low RTD A/ RTD B Temperature Reading
T
his
warning/alarm
appears
when
the
temperature
decreases below the LOW RTD WARNING/ALARM temperature
setting.
CauseofWarning/Alarm:
• Warning/Alarm
temperature
setting
too
close
to
maintain
temperature
• Flow
of
cold
product
• Empty
pipe
• Damaged, wet, or missing insulation
• Heating cablenotsized properlyfor the application
9.4.3
RTD A/ RTD B Failure
This alarm indicates a sensor is not operating properly. The
temperature sensor may fail due to an “open” or “shorted”
condition.
Cause of Alarm:
• Incorrect or damaged field wiring - open leads or excess
resistance (either intermittent or continuous) may be
due to broken or damaged wires or loose terminals.
• Damaged or inoperative temperature sensors
9.4.4
High Current Warning/Alarm
This Warning/alarms current levels that are greater than the
HIGH CURRENTWARNING/ALARM setting for the application.
High Current Warning/Alarm (Continued)
CauseofWarning/Alarm:
• Warning/Alarm
setting
too
close
to
normal
operating
current
• High in-rush current from “cold start” of self regulating
cable
• Damaged or partially shorted heating cable
• “As built” cable length is greater than design value
9.3.4
Low Current Warning/Alarm
This alarms current levels which are less than the LOW
CURRENT WARNING/ALARM setting.
Cause
of
Warnings/Alarm:
• Warning/Alarm
setting
too
close
to
normal
operating
current
• Low
source
voltage
• Damaged or inoperative heating cable
• Open connection—wiring problem
• SSR or contactor failed open
9.3.5
High GFI Warning
This warning ground fault current levels which are greater
than the HIGH GFI WARNING
setting.
Cause of Warning:
• Warning setting too close to normal leakage current
• Damaged cable insulation and/or moisture present
• Moisture
in
junction
box
• Poor
splice
or
termination
• Moisture provides conductive ground path which allows
ground fault current.
9.3.6
GFI Alarm
This value sets the upper limit of allowable ground fault
leakage. Exceeding this limit will result in the output switch
being latched off and the alarm activated to indicate a
ground fault condition.
2
2
