Regarding previous posts on related subject. Does anyone know if the vacuum control hot water valve is designed so that it has a small vacuum leak to enable a linear range of operation or is it sealed off such that it has no leak and only works in an on/off manner no middle of the range settings? Reason I am asking is that mine shows a slight leak, consequently it takes a lots more vacuum to actuate it than the normal controls seem to provide. So for now I can't tell whether the problem is in the control not applying enough vacuum or the valve having this small leak.
I guess I'm gonna have to break down and head to my favorite junkyard.
tks Don