Room Sensing Stat

[agi]

Could you please explain this to me? How does it work? How can you identify if its faulty or working?
... I am talking about the sensor which has long wire and a tube in the end. Its shown in the following link:
Dimplex 86661 TSB Room Sensing Stat (Storage Heaters) - https://www.uk-spares.com/products/heating/domestic/storage-heaters/dimplex-storage-heaters/cxlsn/cxls12n/series-a-14/dimplex-9510094.html

Cheers

 

[telectrix]

clip a meter ( on ohms setting) to the terminals. should read zero ( or close to). warm up the sensor end with a lighter. when warm, the stat. should switch and the meter read open circuit.

 

[agi]

thanks telectrix. why is that? what electrical law is applying to this? It looks like just a metal wire to the earth of the thermostat. (half sleeved, even its not completely isolated) Or this is not a wire maybe some tiny tube etc? Just curious...

 

[telectrix]

it's not electrically operated. it's fluid mechanics.the sensor is at the end of a capillary tube full of a liquid. when heated this expands and operates the switch.

 

[agi]

what kind of fluid is it? Is it not dangerous if it spills out?

 

[freddo]

The last 2 I cut open had kerosene as the liquid. Well it certainly smelled like it and burned like it too.