The water temperature mixer attached to AquaHot failed - a small piece of plastic inside broke off - and the only symptom was low hot water pressure. Replaced the mixer and all is well. Hope this helps someone else.
Larry, I have the same low hot water pressure. Where did you purchase the mixing valve from?
I bought mine here and just used the parts not the housing. Works fine
Watts Mixing Valve, Lead Free Brass 1/2 LF70A-F | Zoro.com (http://www.zoro.com/watts-mixing-valve-lead-free-brass-12-lf70a-f/i/G4531082/)
Zoro.com is another great resource the on-line shoppers should have on their favorites list.