If it's a flapper valve, it's just a larger, stiffer version of a toilet flapper. Those never seal correctly over time, and usually require replacement as normal maintenance within a few years. You could put a ball valve on the outlet end, close that, then have the leaking valve replaced while there's no flow through it if that's actually where the problem is. It could be a crack in the pipe close to and downstream from the valve. If you replace the valve, think carefully about the design.
As to the opening force, it takes tremendous force to open initially, but once there's flow, and the valve has a small opening, the force to open all the way drops off exponentially.
Last edited by John Fitzgerald; 11/13/17 04:48 PM.
