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6.3 COMMON ALARMS—WHAT TO LOOK FOR
The CM 2000 and the CM 2000+ control modules have a wide range of alarming features that may be selectively enabled or disabled
to allow the monitoring and indication of trouble conditions. Described below are the different alarm conditions available on the
control module, their meanings, and possible causes.
Alarm Description Cause of Alarm
High Voltage This alarms voltage levels that are greater than
the HIGH VOLTAGE ALARM setting.
• Alarm setting too close to normal operating voltage
• Incorrect wiring
• Power Surge
• Incorrect VOLTAGE TURNS RATO setting
Low Voltage This alarms voltage levels that are less than the
LOW VOLTAGE ALARM setting.
• Alarm setting too close to normal operating voltage
• Damaged power cable
• “Brown-out” conditions
• Loss of power to the heating circuit
• Incorrect VOLTAGE TURNS RATO setting
Overcurrent
Trip
If the control module is unable to start the cable
due to high current or after attempting to soft start
it, the control module will trip its output switch off.
• SWITCH RATING setting is too low
• 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
• Incorrect CURRENT TURNS RATIO setting
• Incorrect wiring
Switch Failure This alarm will indicate that the control module
senses current flow when the output switch
should be off.
• Some other device energized heat trace
• Output switch has failed ”closed”
HTC Reset This alarm is latched when power is restored after
an interruption. Used to identify intermittent power
losses.
• Circuit breaker tripped
• Power line transient
C.B. Limiting This alarm indicates that the solid-state relay
is limiting the average current that is applied to
the heating circuit to the C.B. CURRENT RATING
setting to protect the heater’s upstream circuit
breaker from tripping.
• C.B. CURRENT RATING setting is too low for normal heater
current draw or not matched to actual circuit breaker size
• 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
• Incorrect CURRENT TURNS RATIO setting
• Incorrect wiring
Power
Limiting
This alarm indicates that the solid-state relay
is limiting the average amount of power that is
applied to the heating circuit as defined by the
MAXIMUM POWER setting.
• MAXIMUM POWER setting is too low for normal heater
power consumption
• 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
• Incorrect CURRENT TURNS RATIO setting
• Incorrect VOLTAGE TURNS RATIO setting
• Power Surge
• Incorrect wiring
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