Old-Biscuit wrote:
That is a 3 way cold inlet shutoff & bypass valve.
Current position with handle parallel with bottom line is OPEN (allows cold water into bottom of WH Tank)
Turn handle 1/4 turn......handle pointing up (parallel with vertical line) is BYPASS position. Stops water from going into bottom of WH and allows cold water to flow thru vertical line up to hot outlet line
In hot outlet line (hidden in picture by flex duct) will be either:
another valve (which has to be closed to stop flow backwards into WH tank via hot outlet)
OR
there is a check valve (internal of fitting on hot outlet)
This sounds likely and I wasn't thinking about the possibility of a check valve on the hot side. That makes most sense. There is not a manual valve, I did check for that. Thanks much old-biscuit!