The Base Unit (dated 2019) SB-H10 (the one without the tall stalk) is displaying water temps of 120-140 degrees.
In reality, the water is 65 degrees.
Obviously, the temperature sensor is "broke". But which one is it to replace?
I've had the unit apart, and I've removed three sensors, cleaned them, and put them back in. I've also left it unplugged for about 6 hours.
There are two sensors with hex head, that seem to bolt into the top and bottom of the heater. and there is one on the plastic discharge pipe (this one does not appear to actually go into the water, and is only held in with a retaining arm). Finally, I don't know if it's a sensor, but there is a black wire wrapped like 60 times around the discharge pipe right before it goes back to the spa.
So which sensor is the one I replace?