Originally Posted by lustreking
I think it will read lower while you are draining from the valve, but will read correctly when it's closed.
it will do this because my HLT Mark I is like that. Full open it drops by nearly a 1/2 gallon mark, but a slow drain is a pretty small drop.
FWIW, I'm going to rework it so the valve is on its own when I get around to HLT Mark II.