leaky backflow preventer & high water pressure

I have a one zone water heating system
thathas a backflow preventer that is constantly leaking water out of
the vent, should I remove it and replace it??? also could that be the
reason why my water pressure is at 30psi?? I'm afraid to turn on the
heating system with the water pressure being that high.....
any suggestions????????????

heat

An automatic fill valve regulates the "cold" pressure in the system. A relief valve relieves any pressure over 30 psi. An expansion tank absorbs pressure buildup as the water heats. And a backflow preventer, if you have a separate one keeps the water from entering your domestic water system. All of these items are interrelated so the failure of any one can cause symptoms from the others.