...thank you for asking Andy!
I just had the chance to do it one time like you said!
Two days where the weather was pretty good drying out.
One day I had no time and the other I left it all open for about
3 hours at a sunny place.
It still doesn't work, and writes on the display "I E I"
Should I try it with a hair dryer?
What can be wrong otherwise?
I have no idea, except changing the system and that the last thing I want to do