Sensors
Several problems can arise with your ThermoClamp sensors. One of the
simplest problems is having the bath sensor fall out of the bath. The bath
sensor (if used) must be in good thermal contact with the bath solution.
The insulation on the bath sensor can also degrade until the bath solution
makes electrical contact with the thermocouple. If the blue Control display
goes blank or shows a strange number, the bath sensor may be shorting to
the bath solution. Try removing the sensor from the bath to see if the blue
display reappears. Make sure you are not grounding the thermocouple
with your fingers. If you suspect broken insulation on the thermocouple,
dip it in epoxy and allow it to dry.
The thermocouples or their wires or plugs can break. This is easy
to observe with a multimeter (ohmmeter) as an infinite resistance
measurement. Check inside the sensor’s blue plug for a loose screw. The
sensors are simply two different thermocouple wires soldered together.
Remove any oxidation build-up on the plugs.
It may be possible for the Pencil TC to short to the inside of the Pencil.
This can be observed as a zero resistance between the Pencil TC plug
(either lead) and the metal Pencil body. If you suspect a shorted Pencil TC,
carefully remove the Pencil’s “wetsuit.” Remove two screws holding the
top of the Pencil. You can see the Pencil TC at the end of its two wires. Dip
the ends of the bare wires into some epoxy for insulation and allow to dry.
Reassemble and test the Pencil.
The ThermoClamp-1 uses standard T-type thermocouples for bath and
Pencil.
Finally, we wanted to mention that most digital voltmeter thermometers
with thermocouples are only accurate to +/- 2˚C. Unless you perform a
multi-point calibration on your digital thermometer, it should probably not
be trusted to calibrate your ThermoClamp.
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