UFH Sensor temperature steadily increases

[Egan7]

I have had wire based ufh under ceramic tiles in the kitchen for a few months. It worked initially then one day the ufh probe underneath the tiles started reading a steadily increased temperature.

It had always been around 2t degrees but then I noticed it increase to 25.5 then 26 etc it's now on 44 and still increasing. The floor in all areas is stone cold. 

Is the sensor broken? Any ideas on how to fix this? 

 

[Geoff1946]

In order of probability, (IMO)

Faulty sensor or wiring to same under flooring

Faulty connection or damaged wire to sensor above floor on way to controller. 

Faulty controller

So, first do a visual inspection of accessible sensor wiring, including its terminations at the controller.

Failing that if you have or can obtain resistance data for the sensor, and have access to a suitable ohm-meter that's how I would approach diagnosis.