Predictive Sensor - Thermocouple Disc. Reading


We have a Predictive Sensor in the field, where it was not ideal to use the thermocouple (or amp clamp). The customer left it detached, and only mounted the vibration puck.
The one we have is the older variety with cable gland, and a thermocouple with a two prong female/male plug to attach the probe to a small lead coming from the sensor.

The customer reported he thought it strange the thermocouple still reported values, even when the thermocouple was disconnected. Not exact values, but fluctuations between 70-80 F (C converted to F).

I was going to try to explain it away, but figured I would ask here to see if I can get accurate explanations?

Why would the thermocouple register temperature readings even when seemingly disconnected?

When you disconect the vibration puck the temperature defaults to 0 celsius. I realize they are difference sensors, and so may work differently. Just wondering why.

The on board thermocouple electronics is still running and it will somewhere around 25-26’C( room temp).

In the vibration case – the electronics is with the vibration sensor probe so when its removed the temp goes 0.