8 Troubleshooting

8.1 Troubleshooting

In the event that the probe appears to function abnormally, this section may

be of use in solving the problem. Several possible problem conditions are

described along with likely causes and solutions. If a problem arises, please

read this section carefully and attempt to understand and solve the problem.

If the probe seems faulty or the problem cannot otherwise be solved, con-

tact an Authorized Hart Scientific Service Center (see Section 1.3) for assis-

tance. Be sure to have the model number and serial number of your probe

available.

Problem Causesand Solutions
Datachanges greater th an
0.1°Care observed •Mechanical shock can cause temperature errors as great
as 0.5°C. If this is observed, first measure and record the
Rtp.Next anneal the PRT at 660°C overnight. Measure the
Rtpagain. The annealing should decrease the Rtp. If the
Rtpis stable, recalibrate the PRT.
Datachanges less t han
0.1°C •Slight mechanical shock can cause temperature errors
less than 0.1°C. If this is observed, first measure and re-
cord theRtp. Next anneal the PRT at 660°C overnight.
Measure theRtp again. The annealing should decrease
theRtp. Repeat the annealing, Rtp measurement cycle
several times. When theRtp is stable, recalibrate the PRT.
If theRtp does not stabilize, contact an Authorized Hart
Scientific Service Center (see Section1.3).
•Oxidation of the platinum sensor may occur after pro-
longed use between 200 – 450°C. This oxidation will
demonstrate itself by an increase inRtp of less than
0.1°C. To reduce the effects of oxidation, anneal the PRT
at 600 – 661°C overnight (12 hr.). Measure the Rtp again.
Repeat the annealing,Rtp measurement cycle several
times This annealing process should returnRtp to within
calibration tolerances. If theRtp is within calibration tol-
erance, the PRT is usable. If theRtp is not within calibra-
tion tolerance, but it is stable,recalibrate the PRT.
Dataunstable •If the data is unstable at the Triple Point of Water (TPW),
check the connector. If the connector is correct, contact
an Authorized Hart Scientific Service Center (see Section
1.3). The PRT may be damaged and need repair.
•If the data is unstable at high temperatures, it may be
due to electrical noise in the system. Reduce the temper-
ature and observe the data. If it is stable, electrical noise
is interfering with the measurements at high tempera-
tures. Check the grounding of the readout device and
the heat source. A faulty ground on either device could
interfere with high temperature measurements. A
ground wire attached to the metal sheath of the PRT
may help to reduce electrical noise interference.
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8
Troubleshooting