It could still be a froze issue. Often when a gauge reads around 10 psi and dont zero out it was from freezing water in the gauge at some point.. Disconnect the line at the back of the gauge if its damaged from freezing it will still stay up around the 10 psi. Only fix is to replace the gauge.
ok, I took off end of hose & then got the gauge out. It looks to be filled with thick brownish gunk. Gauge doesnt move so I need a new one, but what if the tube has more in it? how do you clear the tube out?