Heater turns on automatically and registers high temperatures! Pentair Mastertemp 250

[mntbikingontario]

Power up the heater and it will eventually turn on to the spa setting! Even more concerning is it seems to register 260 degrees in the heater! Didn't realize until I woke up the next day and the heater was on when it shouldn't have been.

Here's a video of it in action:

https://youtu.be/IHs3ZhH-_VU

The heater was installed new may 2011. (and the date on the machine says it was manufactured in Nov 2008!)

 

[mntbikingontario]

I fixed this yesterday! Turns out my printed circuit control board had some corrosion on the non visible side...so I had to remove the control board to see it. The corrosion was shorting a switch and after I cleaned it with rubbing alcohol, the heater now stays in "Pool mode" and doesn't automatically switch to spa.

 

[mntbikingontario]

here's a pic of the corrosion