# What is a single conductor temperature sensor called?

What is a conductive temperature probe called? They're relatively massy metal rods (5-8mm thick, 5-15cm long) that have a single conductor (NOT 2 conductor wire) to connect to the thermostat.

The connecting conductor wire is reasonably thick to (presumably) conduct the heat effectively to the measuring device.

I replaced one in my oven, and my spa has one too.

(I ask, because I broke the wire on my spa one, and searching the internet without a technical continually brings up thermo couples and other sensors)

Updated to help others: I'm looking at something like this is the sort of thing:

• It's called a thermocouple. Search on any of the appliance repair sites and you'll probably find a replacement. – EM Fields Feb 4 '15 at 7:42
• From thermocoupleinfo.com: "Thermocouples consist of two wire legs made from different metals. The wires legs are welded together at one end, creating a junction... When the junction experiences a change in temperature, a voltage is created.". One conductor/wire, therefore no voltage. If it is a thermo couple (makes sense from the name, after all), then it must be a specific type that I can't find the name of. – Stephen Feb 4 '15 at 7:55
• The housing is the other conductor. – EM Fields Feb 4 '15 at 8:21
• Awesome - thanks. So is there a name for this type of thermocouple? So the housing (my "conductor" turns out to be very mildly hollow if it's not crushed) is a conductor, then what's the other conductor? It does have an acidic smelling liquid inside (could it be a chemical reaction from getting wet?). – Stephen Feb 4 '15 at 10:22
• And... not fixable - it seems I need to replace. I've found the replacement thermostat but I don't particularly want to shell out $100... so I just need to figure out what type it is and then search for replacement couples? – Stephen Feb 4 '15 at 10:31 ## 1 Answer This task is often performed by a theromocouple, such as EMFields describe. However ... Your device is a "Capillary Thermostat". The sensor is filled with a substance which increases in pressure with heating and a bellows in the control end actuates a switch at a preset temperature. Once broken they are essentially not repairable. You may be able to find a direct equivalent elsewhere and other versions which cover the same temperature range and which have the same electrical contacts could be used as a replacement. As ever, YMMV.* Another seller here -$ unknown.

Often a very good source if they have something suitable.

[Wikipedia - also known as a 'freeze stat'])(http://en.wikipedia.org/wiki/Freeze_stat)

Real world examples

and more

Lots of pictures - all linked tro related web pages.

*YMMV - Your Mileage WILL Vary.

• I did think that crimp in the bottom was significant somehow... also turns out I had no clue and linked to a High Limit breaker rather than an adjustable... but you still came through! – Stephen Feb 4 '15 at 11:14