Taps come in many shapes and sizes, however, the main physical characteristics are governed by their use, as BATH, BASIN, SHOWER, KITCHEN, or MONOBLOC.
Ceramic versions of the above, usually quarter turn, are vastly different internally. See picture further down.
IF YOU HAVE REPLACED TAPS FOR DECORATIVE REASONS, DON’T THROW THE OLD ONES AWAY, THE TAP BODY CENTRES CAN BE USEFUL. THESE ARE OFTEN COMMON IN SIZE. ONLY THE KNOB SPINDLE VARIES SLIGHTLY IN SPLINE NUMBER AND SIZE.
Bath taps can be single, or mixer type that come as one piece. These are always fed from under the bath by 22MM connectors.
The shower type just has an extra connection and valve on the top for the flexible shower hose. If changing the hose, don’t forget to use the NEW rubber washers that come with the new hose. A large bore type of hose will often improve the flow to the shower head. If the head is heavily scaled, use a proprietary descaler on it, although you CAN use LIMELITE, it takes a while to act.
The basin and kitchen taps are always fed by 15mm pipes, but the MONOBLOC types use only a SINGLE HOLE, and are usually fed by 8mm bore pipes, with M10 or M12 flexible connectors, to 15mm feeds.
Very old taps may have worn valve seats, and worn washers, and although you can re-cut the seats a bit and put in a new washer, it usually is not worth the bother.
On modern taps though, what usually happens, is that the “O” ring seals in the spiral mechanism fail due to scale abrasion, letting water into the spiral. This causes the taps to become difficult to turn on or off, increases wear in the spiral, and may cause either leakage at the spindle at the top, or the tap will not open at all.
A very badly worn tap body can also give rise to horrible noises, and what is called “water hammer”, if the spindle oscillates in and out of the valve seat. You can get a “tap reviver” kit (tap body with matching knob).
When changing a tap, always ensure that you renew the red fibre washer that sits in the groove of the tap connector. The old one might not be recognisable as a washer, so just ensure the groove is clear and clean (use a sharp pointed object to clean it out), and insert a new one. DO NOT TRY TO USE AN “O” RING INSTEAD OF A FIBRE WASHER. IT RARELY WORKS, AND WILL USUALLY LEAK.
When you are next passing a plumbers’ merchant, buy a few fibre washers for tap connectors (half and three- quarter inch), you never know when you will need one and they are not very costly.
ALSO: ensure that a NYLON washer goes between the tap and the basin/bath, and a RUBBER washer goes between the plastic nut, and the underside of the basin/bath*. This will allow you to tighten the tap properly, and stop any tendency to turn, as it might do when using flexible connectors. You should never rely on the feed pipe joint for this anyway.
If you have had to turn the water off at the tank, or main supply, consider fitting service valves each time you replace taps. This will pay dividends next time. These are quite cheap. I would not recommend GATE VALVES for this, as I have had the hot side scale up and seize over time.
If you have found the above useful you will probably find the other tips and guides featured on Lexfixit.co.uk site, including several on Central Heating, invaluable, either now or at some time in the future.
As with most things, there are different viewpoints on any given subject and I have been contacted by Mr. Bob Lawson who advises –
It’s a small point, but you state specifically that the rubber washer fits under the nut, the plastic one between tap and basin. They go the other way round, the rubber one forming the deck/tap seal, the plastic (polywasher) preventing metal to china contact. A rubber one would ruck up when the nut’s turned. It’s often worthwhile fitting a top hat washer under the bath deck.