Watlow Series L
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15
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Chapter 5: Troubleshooting
Indication
Possible Cause(s)
Corrective Action
Limit load is on when it should
be off. ALARM LED is off.
• Power switching device (mechanical
relay, contactor, etc.) is shorted. Limit
output shorted.
• Remove wires from output of limit to
input of power switching device. If
load is still on, replace power switch-
ing device. If load turns off, replace
limit or sensor. See input troubleshoot-
ing
• Output wiring is incorrect.
• Verify wiring
LS Controller
Unable to reset controller af-
ter the limit trips, Limit LED
flashing, Range LED on.
• Temperature above Limit Set Point
Hysteresis Value
• Wait until temperature returns to
safe range
• If temperature within safe range
power must be removed from the
controller for no less than 3 seconds
LS LED Definition
Limit
Range
Limit Relay
Off (open)
Off (open)
On (closed)
Off (open)
Off (open)
Limit Condition - Temperature > Limit
set point or above Reset point.
Limit Condition - Temperature < Reset
point, but reset not yet enabled.
Temperature < Limit Set Point
“Normal Operation”
Ambient Alarm 85ºC
Health Check Error
Flashing
Off
Flashing
LED Status
On
Off
On
Alternate
Flashing
Flashing
Flashing
Limit
Range
Limit
Range
Limit
Range
Limit
Range
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