I started to report this under the Thermostat Failure post but thought I should report the Hydrohot repair success under a new post. Thanks to all of you who took the time to post how to repair the Hydrohot plastic pex water fittings with brass fittings on coaches with no access to the rear of the Hydrohot, mine has been repaired.
After searching high and low for a slow water leak and thinking the pump was going bad as it was cycling on and off every so many minutes, I finally found that the water was leaking down on the floor under the waste tanks. I used a remote camera from Harbor Freight to pretty well know that was where it was leaking only when the system was under pressure. Otherwise, no leak.
I printed off every post I could find regarding others' experiences and called Kevin Stringer of Stringer Enterprises out of Zephyrhills, FL. He dug a trench under the Apex so he could safely lie in it and work on it. Good thing I was on private property. And, yes there was NO access door and he had to cut a hole in the floor to get to the leak. He said he would not even had attempted the repair had I not had the information from the forum that I had printed. With the help of my cousin (a metal fabricator in a previous life) and some tools and metal work and materials from my cousin's shop, Kevin was able to repair the fittings with brass ones. He couldn't believe that WRV installed the Hydrohot with no access for repair but then said after being in RV repair, he believed about anything. It's refreshing to run into RV repairmen who really care about their work.
This summer I will need to get the punky floor repaired when I get home. Special thanks to Basil, Kraig, Engineer Mike and everyone else who took the time to post photos and repair instructions!
Now on to my next adventure! I am hoping it won't be dealing with repairs,