Hi, I recently bought a new Honeywell 4073 3 port valve and used the powerhead part to replace my existing one and it seemed to solve the problem I have been having with my system, but in doing so I noticed that the rotating shaft bit on the valve that the powerhead sits on is stiff to turn by hand on mine but is easy to turn on the new one. Is this because mine is seizing up, hence the old powerhead failing, or is it because the one on my system has water in it making it stiff to turn. I am concerned because I don't want the new powerhead failing for the same reason and I don't really want to go through draining the system down to replace the valve itself unless I have to !?!