Of course, if they're 30 years old or rusting, you may be better off replacing them sooner than later. The 600 likely refers to their psi rating for WOG (water, oil, gas).

Greg

: I just installed a pressure booster (we had 40#, now it's 60#-70#) and all of the sudden all of my ball valves leak (from the stem at the washer/nut joint). It's about a teaspoon per day, so a paper towel under it soaks it, but they shouldn't leak at all...

: Any ideas? I don't have them in front of me, but the valves are Apollo International brand with yellow handles...I thought they had the number 600 on them too, but I would need to check them again to be sure.

: Thanks, Matt