Repairing A Dripping Tap Leave a comment

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  • Pillar tap diagram:
  • Tap indicator covers:
  • Tap valve:
  • Tap washer:
  • Tap valve seat:
  • Valve seat grinder
  • Leaks at the top of the tap:

One of the most common problems encountered in the home and still one of the most misleading…”Change the tap washer” we are told…

Here is a secret ! 99% of the time a dripping tap has nothing to do with the washer which, because is it rubber, is as good as the day it was installed. The problem is normally the valve seat which the washer sits on when the tap is closed. The pressure of the water tries to force it under the washer and little by little it erodes the brass from which the seat is cast. Tiny little canals are formed in the seat which allows water to pass under the washer and out through the tap. This is very often caused by hard water and can quite often be eliminated in the future by visiting . We have detailed below the full procedure for changing a washer and re-grinding the seat. First, turn off the water and, if it an upstairs tap, open one of the taps downstairs to drain the pipes: The principle of “tap operation” is the same with most taps and the diagram below can be referred to for the names of various parts.

Pillar tap diagram:

Tap indicator covers:

Most modern taps have the hot (red) and cold (blue) indicators on the top. These usually hide the screw which holds the handle on.

The handle

also acts as a cover for the valve. Before you start to dismantle the tap, place the

plug in the hole. This will stop you losing anything down the waste.

Removing the cover and indicator will show the screw which can be undone.

The handle should then lift off.

Tap valve:

The next step is to release the valve, but first make sure the tap is wedged firmly in position (if it moves while undoing a tight valve nut, it may loosen the water connection underneath) and place a cloth over the tap to avoid scratching the metal.

Undo the valve completely and remove.

Tap washer:

Some valves have a small retaining nut for the washer, as this one has. Some have the washer simply pushed on to a centre lug. Either way, now you have got this far, you may as well change the washer. Most washers are symmetrical and turning the old one over will give you a new surface to work with.

Tap valve seat:

The operation of the tap handle, opens or closes the washer against the seat, which is a small shelf just inside the body of the tap.

Valve seat grinder:

If your tap has been dripping, more often than not, small canals will have been eroded into the metal of the seat. These can be removed by grinding the rest of the seat down to level of these canals. This will produce a flat, smooth seat for the washer to sit on and seal the flow of water. The seat grinder is a simple machine, available from our tools section on the suppliers page. Scroll down to the bottom to the page and click into the screwfix advert. Go to hand tools and look for plumbing tools.

The correct size serrated cutter for your tap will be the one that just fits through the opening, and the correct size thread is needed to tighten up in the threads which held the valve.

Insert the grinder, tighten up and push down on the handle twisting as you do. Some plumbers prefer to make a full revolution with the grinder, others prefer to twist back and forth to grind the seat down. Always finish with a few, full revolutions to get the seat as smooth as possible.

Remove the grinder periodically and run your finger around the top of the seat, you will feel any remaining indents. Keep grinding until it is smooth and replace the valve etc. Turn on the water. (Don’t forget you may have a tap open downstairs).

Leaks at the top of the tap:

A dribble from the top of the tap is usually a result of the Gland seals being worn. Sometimes there is a gland nut, which can be undone to reveal the O ring sealing the gland to the head. (see diagram at top). Other times there is a circlip holding the spindle to the head. This can be removed carefully as shown below.

In both instances an O ring seal or seals will be revealed and these can be changed by rolling them from the spindle and fitting new.

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