Hi, Long story short; the installer didn't check pressure and didn't install pressure tank, so my water pressure was about 150 psi and the 125psi pressure valve on the solar tank dribbled often enough to leave bad stains on roof shingles. I want to drain the solar tank, disconnect it and move it out of the way so that I can get at the good shingles beneath the water heater and replace the bad with the good, so that my roof will not look crappy. The shingles are discontinued. Question is how to turn it off, drain it, etc hopefully leaving my regular water heater working. I think the red handle below is the cold water inlet to both the regular hot water heater and going up into the solar heater. Will this red handled valve just shut off cold water to both heaters? In other words, I can't just run my regular hot water heater by itself right? I'm not sure what type of valve that is, but it looks like just an on/off 1/4 turn valve. Appreciate any advice.