How Does a Water Tap Work?
- The part of the tap which you turn is the top end of a screw which goes down into the casing of the tap.
- At the bottom end of this screw is a rubber or leather washer which presses down on to the end of the water pipe, preventing the water from coming any further.
- When you turn the tap on, the screw rises, lifting the washer with it and allowing the water to gush up from the pipe and run out through the spout.
- When you turn off the tap, you are screwing the washer down again on to the pipe and cutting off the flow of water.
If there's a leak, it could be one of several problems:
- the washer is not seated correctly (it hasn't been put in quite right),
- the washer needs replacing (go buy a new one! They're very cheap so buy a few spares, or
- the 'seat' needs 'reaming' (it might be a little chewed or worn, there's a special tool you can buy to do this). Alternately and more expensively, you can just replace the whole faucet.
Troubleshooting and Repairing Water Faucets and Valves
Faucets and globe valves, the type commonly used in home water systems, are very similar in construction, and the repair instructions given below apply to both. Your faucet or valves may differ somewhat in general design from the one shown here, because both faucets and valves come in a wide variety of styles.
Mixing faucets, which are found on sinks, laundry trays and bathtubs are actually two separate units with a common spout. Each unit is independently repaired.
If a faucet drips when closed or vibrates ("sings" or "flutters") when opened, the trouble is usually the washer at the lower end of the spindle. If it leaks around the spindle when opened, new packing is needed. To replace the washer:
- Shut off the water at the shut-off valve nearest the particular faucet.
- Disassemble the faucet - the handle, packing, nut, packing and spindle - in that order. You may have to set the handle back on the spindle and use it to unscrew and remove the spindle.
- Remove the screw and worn washer from the spindle. Scrape all the worn washer parts from the cup and install a new washer of the proper size.
- Examine the seat on the faucet body. If it is nicked or rough, reface it. Hardware or plumbing supply stores carry the necessary seat-dressing tool. Hold the tool vertically when refacing the seat.
- Reassemble the faucet. Handles of mixing faucets should be in matched positions.
To replace the packing, simply remove the handle, packing nut, and old packing, and install a new packing washer. If a packing washer is not available, you can wrap stranded graphite-asbestos wicking around the spindle. Turn the packing nut down tight against the wicking. Other faucet parts may be replaced as necessary.
Complete faucet inserts in which the washer does not turn on the seat are available. This feature prolongs washer life indefinitely.
Several new faucet designs aimed at easier operation, eliminating drip and promoting long service life are on the market. Instructions for repair may be obtained from the dealers.
If a shower head drips, the supply valve has not been fully closed or the valve needs repair.
After extended use and several repairs, some valves will no longer give tight shut-off and must be replaced. When this becomes necessary, it may be advisable to upgrade the quality with equipment having better flow characteristics and longer-life design and materials. In some cases, ball valves will deliver more water than globe valves. Some globe valves deliver more flow than others for identical pipe sizes. Y-pattern globe valves, in straight runs of pipe, have better flow characteristics than straight stop valves.