Fluke 7381 - Troubleshooting

7381
User’s Guide
52
Troubleshooting
Tab l e 6 contains information to troubleshoot the Product. This information pertains to a number of
bath models and certain specifics may not pertain to your model.
If the Product appears to function abnormally, this section may help to find and solve the
problem. Several possible problem conditions are described along with likely causes and
solutions. If a problem arises, read this section carefully and attempt to understand and solve the
problem. If the probe seems faulty or the problem cannot otherwise be solved, contact Fluke
Calibration for assistance. Make sure to have the model number and serial number of your
Product available.
Table 6. Troubleshooting
Problem Causes and Solutions
The heater indicator LED stays red
but the temperature does not
increase.
The display does not show
Cut-out or show an incorrect
bath temperature, but the controller otherwise appears
to operate normally. The problem can be either
insufficient heating, no heating at all, or too much
cooling.
• One or more burned out heaters or blown heater
fuses can also cause this problem. If the heaters
seem to be burned out, contact Fluke Calibration for
assistance.
The display flashes
Cut-out and the heater does not
operate
The display flashes
Cut-out alternately with the process
temperature.
• If the process shown temperature seems grossly in
error, consult the problem: The display flashes
Cut-
out and an incorrect process temperature.
• Normally, the cutout disconnects power to the heater
when the bath temperature exceeds the cutout set-
point causing the temperature to drop back down to
a safe value. The heater only comes on again when
the temperature is reduced and the cutout is
manually reset by the operator, see Cutout Set-point.
Check that the cutout set-point is adjusted to 10 °C
or 20 °C above the maximum bath operating
temperature.
• If the cutout activates when the bath temperature is
well below the cutout set-point or the cutout does not
reset when the bath temperature drops and it is
manually reset, then the cutout circuitry or the cutout
thermocouple sensor may be faulty or disconnected.
Contact Fluke Calibration.