59
Overcurrent Trip If the controller is unable to start the cable due to high
current or after attempting to soft start it, the controller
trips off its output switch.
• Excessive in-rush current
• Incorrect wiring
• Damaged cable
• Switch rating set too low
• Incorrect
CURRENT TURNS RATIO setting
Switch Failure This alarm will indicate that the controller senses current
flow when the output switch should be off.
• Some other device has energized the heat trace cable
• Output switch has failed
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
Power Limiting This alarm indicates that the solid-state relay is limiting
the average amount of power that is applied to the trace
circuit as defined by the
MAXIMUM POWER setting.
• Power applied to trace circuit is being limited to the
MAXI-
MUM POWER
setting
• Incorrect
VOLTAGE and/or CURRENT TURNS RATIO setting
C B Limiting This alarm indicates that the controller is limiting the
average current to the
CIRCUIT BREAKER CURRENT RAT-
ING
setting.
• Excessive current caused by in-rush current
•
C.B. CURRENT RATING setting too low for normal heater cur-
rent draw or not matched to actual circuit breaker size
• Incorrect
CURRENT TURNS RATIO setting
Switch Limiting This alarm indicates that the controller is limiting the
average current that is applied to the trace circuit based
on the
SWITCH RATING setting to protect the solid-state
relay from excess current.
• Excessive current caused by in-rush current
• Incorrect
CURRENT TURNS RATIO setting
High Resistance This alarm indicates that the heating cable resistance has
deviated from the
NOMINAL RESISTANCE setting by more
than the
HIGH RESISTANCE ALARM setting.
• Alarm setting too close to actual operating resistance
•
NOMINAL RESISTANCE not set properly
• Open connection—wiring problem
• Damaged cable
• Incorrect
VOLTAGE and/or CURRENT TURNS RATIO setting
Low Resistance This alarm indicates that the heating cable resistance has
deviated from the
NOMINAL RESISTANCE setting by more
than the
LOW RESISTANCE ALARM setting.
• Alarm setting too close to actual operating resistance
•
NOMINAL RESISTANCE not set properly
• Partial short—wiring problem
• Damaged cable
• Incorrect
VOLTAGE and/or CURRENT TURNS RATIO setting
EEROM Data Failure This alarm indicates that the controller has detected a
failure in its nonvolatile memory (this is where all of the
controller’s configuration and calibration settings are
stored). This indicates an internal problem and the
HTC
should be replaced and returned to Tyco Thermal Con-
trols for repair.
• The
HTC cannot bypass the failed area of its memory and
has loaded factory defaults into this failed area.
Contactor Count
(V3.11 and up)
This alarm indicates that the number of off-to-on transi-
tions of a contactor has exceeded the
CONTACTOR
COUNT ALARM
setting and needs to be replaced.
• Contactor may be worn.
• Some configuration parameter (i.e.
DEADBAND, AUTO CYCLE
INTERVAL
, load shedding etc.) is causing the contactor to
toggle more than usual.
6.3 Common Alarms—What to look for (Continued)
Alarm Description Cause of Alarm
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