Conair Thermolator TW-S User Manual page 80

Con tr oll er Alar ms
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
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.
6-8 I Tr o u b l e sh o o t i n g
Possible Cause
2
Is the cooling valve stuck open

or leaking water?

Did a heater element fail or
open?
Did a heater contactor fail open?
Is the low process temperature
alarm too sensitive?
Is the low deviation temperature
alarm delay too short?
Is the initial deviation alarm
delay parameter too short?
Is the Thermolator under-sized
for the application?
Is the Thermolator or equipment
to which it is attached leaking?
Are the algorithm and PID pa-
rameters set correctly?
(Continued)
Solution
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.
Repairing Cooling Valves.
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.
Replace the contactor if defective.
See Replacing the Heater Contac-
tor.
Modify the Low Deviation Alarm
trigger point by increasing param-
eter .
Modify the Low Deviation Alarm
trigger point by increasing param-
eter .
Modify the "Startup Ignore Devia-
tion Delay" by increasing param-
eter.
Review specifications and selection
guidelines that apply to heater and
pump sizes in temperature control
units.
Verify that there are no water leaks.
Fix as necessary.
Check the algorithm/PID param-
eters: t, Pb, E,n, PbH,
EH,nH, and Pbr.
(Continued)
See