I was told to look for a number when testing it. It was either ohms or resistance, I can't remember. :doh
Reeeeeeeeeeeeee-wind :nenau are you talking about the thermostat that lives in your hot water system? 'cause I am. It simply opens up when it gets hot , like say 85 degrees.
To test, bung your "stat" in a pan of water on your tin tent's billy stove. Apply gas and heat up while observing your handy tin tent thermometer , or your mum's jam making one. At about 85 degrees the thermo"stat" should open
It's like magic and requires no multimeter gizmo ohmage :lol
Enjoy