I've got the same water sensor error. first noticed a problem a week or so ago when the air and the water temps appeared to be flipped around on my aqua pod controller; now, the controlled says "wtr sensor open". I've traced the line leading from the sensor (located between my filter and the heater) and could not find any corroded areas or anything that was obviously damaged. I looked online for a replacement sensor and wire and found several sites. My question concerns installation of a replacement. The replacement parts I saw all had stripped wires at the end that would control to the control box, rather than any kind of plug in connector. Since the wire goes in on the underside of my box, which is essentially at ground level, I'm not sure how that would work. How is the connection made into the control box? I'd try to look myself with a mirror or disconnected the existing wire myself, but I've got a hip problem that is going to prevent me from getting down that low for awhile.
I'm using a Hayward system.