vertical? I have mine sitting on the bottom of my sump, completely horizontal. I didnt no you had to mount them vertically. Either way i dont think it matters. Mine has been functioning perfectly for some time now.
The above is directly from the instructions. This is the less-expensive unit, not the one with the digital readout. I think from the fact that none of you have had any problems, then there is no need for me to worry either.
Wow! Maybe I read my directions wrong. I have the same one you do and I swore it said that. Oh well, eitherway I have had it horozontal for several months now without any problems.