Conair Thermolator TW-S User Manual page 81

C ont ro ller A l ar m s
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
22 22

HSU 24
User Temperature – High Limit
The process temperature has risen
beyond the user-configured maxi-
mum high 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-
junction 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
Has water stopped flowing
thought the unit or between the
supply outlet and return inlet?
Did the cooling valve fail closed? Check the cooling valve.
Is the temperature difference
between the cooling water supply
and the setpoint too small?
Has the heater contactor failed
with the contacts welded closed?
Is the cooling valve under-sized
for the application?
Is the high process temperature
alarm too sensitive?
Is the cooling water return line
plugged?
Has the cooling water return
pressure risen?
Has the cooling water supply
pressure dropped?
Solution
Verify that the unit is running and
that the pump is working.
Check for closed or defective
cooling or vent valves and plugged
lines.
See Repairing Cooling
Valves.
Check for external closed valve on
the process fluid going to external
equipment.
Check for a plugged pipe.
See
Repairing Cooling Valves or the
Motorized Cooling Valve instruc-
tions.
The temperature difference should
be at least 25°F {14°C} to achieve
proper cooling. Increase the pro-
cess setpoint, decrease the cool-
ing water supply temperature or
increase the cooling water supply
pressure.
Replace the contactor if defective.
See Replacing the Heater Contac-
tor.
Check the cooling load (Btu/hr) for
which the valve was specified.
Increase the alarm trigger point
HSU
. The recommended setting
is the setpoint plus 2° F {4° C} to
10°F {18° C}.
Verify the free flow of water out of
the unit.
Check the water return pressure
with valve.
Check the water supply pressure. If
equipped, verify that strainer is not
clogged.
(Continued)
Tr ou bl e s h oot i n g I 6-9