Solar not turn on under hot weather

[binbino]

I noticed my solar is not on in easytouch control panel despite the hot weather.

Looking into diagnosis I noticed my water temp is 74, air temp is 83, but solar temp is 245.

The solar temp looks ridiculous. Is that the reason why solar is not on? How can I fix this?

 

[mknauss]

Something is wrong with the Solar thermal sensor.
@Dirk @mas985

 

[Dirk]

How handy are you? Those three sensors connect to the EasyTouch circuit board via simple terminal screws. [AFTER TURNING OFF ALL CIRCUIT BREAKERS TO THE PAD] You could swap the air and the solar sensors at the circuit board and see what happens. If you get the same wonky numbers, it might be the board. But if the wonky number moves from the solar to the air, then you've got a bad solar sensor. Those are easy to replace.

Amazon.com

The odd bit, is that the ET is looking to make sure there is enough heat on the roof before it engages the solar. 245° is certainly enough heat, so the fact that the ET didn't engage the solar is not a good sign, like there's something amiss with the board. Perhaps it has some sort of max temp safeguard? In which case it's doing what it's supposed to, but that's just a guess. Do the simple troubleshooting step first, then we'll go from there.