6-8
I
Troubleshooting
Controller Alarms
When an alarm occurs, the Thermolator has detected a problem with the process. Without correction, the
TCU will not be able to produce process fluid of the correct temperature. Under certain conditions, an
alarm could lead to equipment damage or personal injury if it is not corrected.
•
The controller displays an error code indicating the cause of the problem.
•
If the optional alarm package is installed, the Fault strobe will illuminate and the audible alarm will
activate.
Alarm
Possible Cause
Solution
2 2
Deviation Alarm – Under
Setpoint
The process temperature has
dropped below the allowable
deviation window for a certain
amount of time.
WARNING:
Only qualified elec-
trical service personnel should
examine and correct problems
that require opening the unit’s
electrical enclosure or checking
electrical current.
u
ALARM LED flashes in con-
juction with an alternating
actual temperature display.
u
Optional strobe, sounder, dry
contacts actuated.
u
Pump continues to run nor-
mally.
u
Heater continues to run
normally.
u
Cooling valve continues to
run normally.
This alarm will automatically
reset when the problem is cor-
rected.
Is the cooling valve stuck open
or leaking water?
Disassemble the cooling valve and
check for particles blocking the
valve seat. Check the valve seat
for excessive wear. Replace as re-
quired using a valve repair kit.
See
Repairing Cooling Valves.
Did a heater element fail or
open?
With the unit powered down: Check
for loose connections on heater wir-
ing. Check resistance between the
phase legs on the output side of the
heater contactor (or SSR if present).
Readings should be within 0.25
ohms of each other. Replace the
heater, if necessary.
See Replacing
Heater Elements.
Did a heater contactor fail open?
Replace the contactor if defective.
See Replacing the Heater Contac-
tor.
Is the low process temperature
alarm too sensitive?
Modify the Low Deviation Alarm
trigger point by increasing param-
eter
.
Is the low deviation temperature
alarm delay too short?
Modify the Low Deviation Alarm
trigger point by increasing param-
eter
.
Is the initial deviation alarm
delay parameter too short?
Modify the “Startup Ignore Devia-
tion Delay” by increasing param-
eter
.
Is the Thermolator under-sized
for the application?
Review specifications and selection
guidelines that apply to heater and
pump sizes in temperature control
units.
Is the Thermolator or equipment
to which it is attached leaking?
Verify that there are no water leaks.
Fix as necessary.
Are the algorithm and PID pa-
rameters set correctly?
Check the algorithm/PID param-
eters:
t
,
Pb
,
E
,
n
,
PbH
,
EH
,
nH
, and
Pbr
.
(Continued)
(Continued)
Summary of Contents for Thermolator TW-P
Page 6: ...iv I Table of Contents ...
Page 12: ...1 6 I Introduction ...
Page 36: ...3 14 I ...
Page 58: ...4 22 I Operation ...
Page 72: ...5 14 I Maintenance ...
Page 128: ...E 4 I Appendix ...
Page 134: ...G 4 I Appendix ...
Page 136: ...H 2 I Appendix ...