Hi Headonis,
I get the E3 error if the humidity measurement goes outside a predetermined range. While the controller specifically stated that it worked from 10%-95% humidity (or something like that), as soon as the humidity goes above 80% or below 20% (those numbers are from memory only!) the E3 error flashes.
I don't believe that it's a contact error. Find a way to reduce or increase the humidity to somewhere between this range and then switch the unit on again. Wait a minute or so, and it should come back to life.
Let me know how you go! This worked for me at least...