My first instinct was to put an ohmmeter on it as well - it remains open all the time, regardless of wet or dry, or orientation. The last thing I did was try that 16V power to see if it would activate with water, so I dont know if that burned the contacts. I have more sensors since I ordered a spare so not a big deal. At this point I dont think this is a simple off/on switch - there must be some intelligence in there that needs voltage.
When I wire it for normally closed (power from the window/door sensor to the green) it says that it is closed all the time which is good, except when I put it in water nothing happens. The retailer was not able to help me yet, so not sure.
I also ordered a low temp sensor from the same company. It does have a recommended dialer to be used with so looked at the specs of it: min 5V and max 28 volts going to the sensor circuits. The temp sensor is speced as normally closed BUT it remains open when I check it with an ohmmeter. It remains open on when on the DS10A in either cofiguration. Perhaps 2.5 volts just is not enough power to run it
It looks to me as though these can't be made to work with X10 because of the low voltage, but I am only guessing at this point. They certainly dont work if you just hook them up, so I'm not sure if there is another way.
thaks for the pointers, looks like the search continues for me.
Bruce