Whether above ground or below, the gate valve is a versatile mechanism used to control a large amount of water in piping. They are designed for fully open or closed use and typically installed in pipelines to serve as isolating valves. When functioning properly, gate valves stop or start water flow quickly without leaking in the process. When dripping from the gate valve begins, it's more than likely a worn washer or other packing system.
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Basic Design of a Gate Valve
The gate valve moves up or down on the threaded stem when in operation. The popular pipeline flow system uses a wheel to move up and down. When the wheel is in its lowest position, the water is halted from its journey down a pipe. When the gate is at its highest position, the water flows freely.
How It Works
The pressure in the gate valve is maintained because nothing obstructs the water flow as in other valves. At the same time, the valve is opened by a series of turns, making the water ease into position so that it doesn't damage the appliance or pipeline or create water hammer effects. The water flow can be regulated by opening or closing the valve to a precise measure. If the gate valve trembles or shakes in a specific position, it isn't holding the water pressure well and should be adjusted. Most household gate valves are intended to be fully open or closed.
How to Repack a Gate Valve
For most valves, the water to the house doesn't need to be shut off. The water supply to the gate valve should be turned off at the main valve, which is usually found up the water stream from where the leaking valve is located. Open the faucet fully and place a wrench beneath the packing nut of the gate valve. Put a second wrench on the valve while turning the first wrench to remove the valve assembly. Use a socket wrench to remove the retainer nut and carefully lift off the faucet handle. Pry off the faulty packing washer inside the packing nut. Clean out any debris or hard water buildup. Place the new packing washer on the scrubbed surface inside the packing nut and slide it back over the valve stem. Secure it to the valve assembly with a wrench. Attach the faucet handle to the valve assembly and thread the retaining nut before tightening the faucet with the socket wrench. Ensure that the assembly is snug at all locations and close the valve. Turn on the water supply and examine the assembly for leaks. It could just need a bit of tightening.