124 708-DS / 709-DS Operator’s Manual
5 Maintenance and Troubleshooting
 
Water Bath Temperature Probe Accuracy Test
The temperature probe can be tested using a high-quality ohmmeter 
capable of at least four-digit resolution and a known temperature bath. 
Both the multi-meter and the bath temperature must be traceable to a 
known reference standard such as NIST.
1 Place the probe into a water bath with a known temperature and 
allow several minutes for the probe to equilibrate.
2 The resistance is measured by attaching the leads of the multi-meter 
to the top and shank of the ¼-inch phone plug.
3 Refer to the table on Page page 124 to find the resistance value of the 
probe at the bath temperature. Temperatures between the values 
listed may be interpolated.
4 Probes are interchangeable and manufactured with a tolerance of +/- 
0.1 °C. Probes found to be outside of the tolerance of +/- 0.1 °C 
should be replaced.