Deve,
Lots of thermisters have been engineered into building temperature controls (thermostats). Contact Kele at
http://www.kele.com/ and see if they have a circuit board that will work for you. They have a great engineering staff and are very knowledgable. No sense re-inventing the wheel...
You would need to encapslate the thermister and wires that passes through the brass fitting to make them water tight.
Mike B
