Ball valves are a common variety of
pool valve found on pool plumbing. Relatively
inexpensive to purchase, and simple to use. Good
replacement valve for old brass gate valves.
disadvantage to these valves is that they are
not serviceable, that is, they cannot be opened
up to make repairs or clear clogs from the valve.
The handles on ball valves tend to break rather
easily, and they can also be somewhat difficult
to turn, especially if installed in an awkward
advantage is their cost ($10 - $15), and ball
valves tend to be easier to understand for novice
pool operators than the three way type valve. Broken valve handles are common, so grab this valve near the center of the handle. If pliers are needed, use a large channel lock type, again grabbing near the center of the handle while turning.
Here is a rather complicated look at a pool/spa system using both ball valves and 3 ways valves, with valve actuators.
Valves for sale >>here<<