POOL GATE VALVES
Gate valves, also known as sluice valves, are very similar to the garden hose spigot outside. This type of valve is not used on new pool installations, but were a common valve used on pools built before 1975. They operate by raising and lowering a door (commonly called a paddle), as the handle is turned. Like a hose spigot, they are “lefty-loosey, righty-tighty”, or turned CCW to open, and clockwise to close the valve. Inside the valve is a paddle, and turning the handle will raise or lower the paddle.
Old gate valves are commonly found to be leaking air and or water. You can repair a leak using valve packing, which is commonly a braided cotton string, impregnated with wax. Open the valve all the way, and remove the handle and then remove the nut. Pick out the old packing seal, and replace it with 4-5 wraps of valve packing sealant.
Since these valves are constructed of brass, a threaded metal fitting is used to plumb the valve. In the absence of threads, slip or smooth ports can be attached to copper pipe with flux and solder, sweated in place with a torch.
Gate valves may be replaced with something of a plastic variety if they leak (air or water) or if the handle just spins and spins, which usually indicates that the stem has detached from the paddle, or become stripped. Over time, chemicals and water flow will deteriorate the paddle, until a hole is eaten right through the middle, in which case a replacement valve is certainly necessary.