The Water inlet valve fails very quickly-3 weeks after replacement

I replaced the water inlet valve after repeatedly getting fault F/H. I determined that the old valve was faulty by blowing through it. The Hot water had a tight seal but the cold water didn't close all the way. I checked for scale but the screens were clean. Lots of water pressure available from the supply lines. Any ideas? Any easy way to repair these valves rather than replacement? Thanks!!