Ok I have a little problem now. One sensor has 3 wires The $50.00 sensor and the $70 sensor has two wires. When I test the sensor with three wires at 71F between one set of the three wires I get a reading of 2.22 kΩ which looks normal and when I test another set of wires I get a reading of 79.6 kΩ. last when I test the third option between wires I get OL.
Now on the other sensor I get no reading at all. Additionally when I set my meter for continuity with a beep I get no continuity and no beep. I'm not sure if that means the sensor is dead or what. I have to dig into the manual again to see if it specifies what wires I should be testing on what sensor. and also find out what it says about each sensor. From what I recall it does not specify any differences between the two sensors. So this leads to more confusion on my part.
When I pull the lower unit "soon" I will plug a hose into the line coming form the pump housing up into the block with the T-stats out and turn the water on from my garden hose and see what kind of flow I get at each T-stat exit port.