I had not considered the coax bringing water into the shack but it is possible. As I stated the fluid leaking out of a tuner(any electronics for that matter) is a concern. I will be putting up a new antena soon and will be very mindful to seal the coax at the antenna. Thanks for the tip, Mike KE4ILG GySgt USMC Ret.
I'm assuming your tuner isn't designed for such high power as to require water cooling?
Did you disconnect the coax at the tuner and check?