Conair Thermolator TW-S User Manual page 83

C o ntro l ler Al a r 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
8 8

SU 
User Temperature – Low Limit
The process temperature has risen
beyond the user-configured mini-
mum low limit.
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 can be reset by
pushing the Alarm Silence/Reset
button once the temperature
returns to an acceptable level.
(Continued)
Possible Cause
Is the cooling valve stuck open
or leaking water?
Did a heater element fail or
open?
Did the heater contactor fail
open?
Is the low process temperature
alarm too sensitive?
Is the Thermolator under-sized
for the application?
Is the Thermolator or equipment
to which it is attached leaking?
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.
Decrease the alarm trigger point
SU
. The recommended setting
is the setpoint minus 2°F {4°C} to
10°F {18°C}. Replace the contac-
tor if defective. See Replacing the
Heater Contactor.
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.
(Continued)
See
Tro ub l es hoo ti n g I 6-11