Tap and Valve Maintenance

This is a breakdown of a basic style 15mm tap, mainly used in basins, sinks and in 20mm bath taps. The main parts for maintaining are the 'o' ring in the spindle assembly and the jumper washer, plus the spindle threads need re-greasing when the tap becomes stiff to turn, this helps stop the metals binding. 

If the tap is leaking out of the spout, then the jumper washer is worn or faulty or the seat inside the tap body is chipped or cracked. 

If the tap is leaking out of the cover when the tap is running. then the o ring on the spindle needs replacing. 

If the seat inside the body is chipped or cracked it can be 're-seated' (ground down until flat with no imperfections) with a re-seating tool

This is a breakdown of a mixer tap, these have now replaced a lot of separate hot and cold two tap systems,

They allow the hot and cold to be mixed at whatever rate is set via twisting the handle, raising the handle controls the flow,  this then comes out of the single spout. The hot and cold is mixed via the cartridge with ceramic disc that slide over one another to allow different flow rates of hot and cold.

These are generally maintenance free, but the cartridges can be replaced once the ceramic discs wear and water drips out of the spout. Normally this occurs towards 10 years or so later and the tap is looking worn and the price of some cartridges are nearly the price of a new tap.

Shower mixers work exactly the same way, but with the mixing body in the wall.

This is a type of shower mixer called a Feltonmix made by Felton, it uses a rotor to mix the incoming hot and cold together. they come in 3 different types; Unequal pressure, Equal low pressure and Equal high pressure.

The unequal pressure is most commonly used in low pressure HWC systems as the incoming cold is of a different pressure than the hot, the rotor uses the cold to help pull the hot through the rotor via venturi creating a higher flow shower.

The equal high is used in mains pressure systems as the pressure are both high.

The equal low is used on low pressure systems where the cold has be joined to the pipework after the Pressure Reducing valve, so the hot and cold are both equal.

There are maintenance washer kits available for these mixers, they replace the O rings and the rotor seat seals and springs. 

This is a breakdown of a Pressure Reducing Valve this is used in low pressure HWC systems. The part that will need servicing is the jumper washer that sits on the inlet jet seat.

The pressure reducing valve works by increasing the force that the low pressure side has over the incoming, it does this via a rubber diaphragm of very much greater surface area than that of the incoming pressure side valve opening (Jet on the diagram). So it take's an extreme amount of incoming pressure to overcome the low pressure side.

When water is drawn from the HWC the pressure on the low side drops allowing the incoming to push through the valve opening and through the outlet. 

The adjusting screw is to change the tension created on the spring and diaphragm to adjust the pressure needed for the HWC system, usually measured in meters of head. The max pressure for low pressure system is 7.2m of head.

If the vent or pressure relief valve is constantly flowing or dripping water, then the jumper washer will probably need replacing, if this is because the jet seat is damaged then a new valve is needed.

If there is water coming out of the adjusting screw, then the diaphragm is worn or damaged letting water through and a new valve will be needed.

This is a break down of a inlet side of a common ball valve.

This works by water coming in from the supply inlet through the valve nozzle, and when the arm is down passed the open washer on the slide valve, then through the outlet. When the fixture that the ball valve is filling the water starts to rise,  pushing up a float on the end of an arm this pushes the slide valve with washer against the valve nozzle shutting off the water to the outlet. 

The end cap is for removal of the slide valve to replace the washer when it gets worn, this can be seen by water dripping out of the outlet eventually overflowing the fixture.

These where commonly used in older toilet cisterns but have been replaced by a more upright floatation shut off valve that takes up less space. 

They are still commonly used in ceiling tanks supplying water to the house or HWC and water troughs.

This is a picture of a upright floatation shut off valve they are commonly called a 'Fiuldmaster' they have replaced a lot of the old ball valve systems because of the space saving and they fill up the fixture with water quicker.

They are maintenance free containing no serviceable parts so are replaced when faulty.