Don't want to hi-jack the thread, but is it just me or are there fewer valves in a nuclear power plant? :h
Unfortunately the diagram and the manual don't provide any insight into how the manifold or valves are actually plumbed. A couple of things to check. The manual mentions a water heater bypass valve like it is not in the utility bay, probably behind the water heater. Another culprit that congressionally causes issues is the outside shower, or the inside shower for that matter (although I assume the inside shower gets enough use that it would have been discovered). The showers can be shut off at the spray handle but the hot and cold valves be open allowing water to circulate through the fixture.
2018 Forrest River Salem Hemisphere 282RK - 2017 RAM 1500 TV
Previous RVs and TOADS
2004 Fleetwood Bounder 32W on WH W20
2000 Four Winds 5000 21RB
1986 27' Allegro
TOADS
2005 Ford Ranger XLT 2WD
2004 Suzuki Aerio
1988 Chevrolet Sprint