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3.11 Troubleshooting
Problem Cause Corrective Action
Large overshoot of the set point
(> 3o) during initial warm-up or unstable
temperature control.
The thermocouple might not be correctly
placed in the solution being heated.
Properly immerse at least ¼” of the
thermocouple directly into the solution
being heated.
The controller is not tuned for the process
being heated.
Tune the controller as outlined in Section 2.
The solution level is below the heating
element level
Turn o the upper element.
The controller comes on but does not heat.
An internal power fuse has blown
Must be serviced by a qualied electronics
technician.
The over temperature protection circuit is
engaged.
Set the limit controller to a temperature
higher than that shown on the setpoint
controller, then press the reset button (see
Section 3.3).
Controller blinks: “inPt” “FAiL”
The temperature sensor is unplugged,
excessively corroded or broken.
Clean or replace broken sensor.
Controller blinks: “-AL-”
The process temperature is hotter than the
alarm temperature.
Correct the over temperature condition.
Controller blinks: “PArk” Controller has been placed in “Park” mode.
1. Hold in both the
and
keys on the
front of the temperature meter until
”tunE” appears in the display.
2. First hold in the “*” key, then while
holding in the “*” key press the
key
until “oFF” appears.
3. Hold in the
and
keys until the
temperature appears in the display.
The displayed temperature is incorrect. The controller has not warmed-up.
The display temperature reads low when
the controller is rst turned on, but will
self-correct as it warms up. The controller
can be used immediately since it will warm
up during the initial stages of heating.
Thermocouples display negative
temperatures, but are not calibrated for
them
Wrong type of thermocouple is plugged
into controller.
Thermocouples are color-coded.
Thermocouple plug and thermocouple
receptacle must be the same color (see
Section 3.6).
Corroded thermocouple connections.
Clean plug on thermocouple and receptacle
on controller with sandpaper or steel wool.
Corroded thermocouple.
If the temperature-measuring end of
the thermocouple is corroded, discard
thermocouple.
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