Different Types of Ball-Valves

As you might know, a ball-valve is what controls the flow of water into a cistern and it works by a ball, made of either plastic or metal, floating on the surface. This ball is what opens and shuts off the supply of water, depending on water levels. There are different types of ball-valves and which one to use depends on the water pressure in question. The three main types of ball-valves are diaphragm ball-valves, equilibrium ball-valves and piston ball-valves. In this article I will tell you a bit more about these.


Diaphragm Ball-Valves

These types of ball-valves were developed as a solution to overcome the quite noisy piston type ball-valves. There is no moving piston in these ball-valves but instead – a rubber diaphragm. The rubber diaphragm closes over a type of nylon seating at the end of the float arm movement. You can buy them in either brass or plastic depending on how much you want to spend.

Equilibrium Ball-Valves

Just like diaphragm ball-vales were developed to overcome an issue, so were the equilibrium ball-valves. The issue in this case being the ‘water hammer’ created when ball-valves are shutting off too fast. The flow of water is operated by the movement of the float arm. This means that the pressure of the water in the mains pipe cannot open the valve. However, once the valve is open, it is balanced by an equal water pressure on both sides of the piston.

Portsmouth ball-valve

Piston Ball-Valves

This is the simplest type of ball-valves and comes in different designs. One of these designs is the Croydon. It works by a vertical falling piston that goes against a nozzle but as it happens, this design is more or less outdated. Another type of design is the Portsmouth which is normally found in domestic properties. In this design, the float arm closes over a horizontal piston which is fitted with a washer and sits against the valve seating. The main negative with this design of piston ball-valves, is that they are noisy when in use so silencer tubes used to be fitted to them but they are no longer allowed.

Equilibrium/Diaphragm Ball-Valves

A good solution that combines the best qualities of the equilibrium ball-valve and the diaphragm ball-valve is the well-named ‘Equilibrium/Diaphragm ball-valves’. These types of ball-valves are also known as the Torbeck and they combine equal water pressure with the closing of the diaphragm. Torbeck ball-valves are quiet, compact and best of all – maintenance free!


Cistern ball-valves of all types are fitted with a BSP screwed inlet and this is for the tap connector. New regulations state that they have to be adjustable and it is because of this that the Portsmouth version is no longer in use.

Cold Water Plumbing and the Direct System

Cold Water Plumbing

When it comes to cold water plumbing, water travels from your main stop-valve via the rising main. From here it can be directed in one of two different ways – through an indirect cold water supply (this is the more common way) or through a direct cold water supply. In this article, I will tell you a bit more about the latter one and discuss some of the pros and cons with both systems.

Hot and cold pipes

Direct Systems

Just like it says in the name, when it comes to direct systems, all pipes and WCs that carries cold water are directly connected to the rising main. In most houses where central heating has been installed, you might find a so called feed-and-expansion cistern or even a hot water cylinder cistern. With a direct plumbing system, there are several different ways to supply the hot water but the two most common ones are through combination boilers and gas heaters with multi-points.

Direct or Indirect Systems?

Despite the direct plumbing system being cheaper to install and also less complicated to work with, many water companies nowadays prefers the indirect system and some of them only allow for this system to be used. The water companies’ say that indirect systems are better for busy periods like early mornings, as they will have less of an impact on the mains. Another thing that the water companies’ also like with indirect systems is that a householder’s own water system is mainly kept separate from the mains supply. This means that there is lesser of a risk for the mains to be contaminated through a backflow. A backflow is where dirty water from a household is being sucked backwards and up the mains. It is very important for water companies to provide and maintain a high quality of water and according to regulations, all water systems should have a device of some sort, preventing backflows from happening. There are some positives for the householder as well when it comes to indirect systems. By having a cold water cistern, you will always have a reserve of water, should you suffer a water cut. The indirect system is also quieter than the direct system.

Warning hot water

However, there are drawbacks to the indirect system as well. They could provide a less than ideal ‘head’, so if you are a fan of a decent shower, you might want to look elsewhere. There is also a higher risk for indirect systems with a cistern and pipe work in the loft to freeze, if they are not correctly insulated but both of these issues can be rectified by using an unvented hot water system.

Cold Water Plumbing and the Indirect System

Cold Water Supply

As you probably know, water travels to your house via the water mains. Your house will have its own branch service pipe with a stop-valve – this is the water company’s stop-valve. Leading from the water company’s stop-valve to your house’s own main stop-valve, is the service pipe. It is from this point on that your own supply starts. Once water has reached your main stop-valve, it is moved along via the rising main. The cold water supply can work in two different ways: indirect and direct. The indirect cold water supply is the more common version and it works by the rising main going directly to the cold water cistern and the cistern can generally be located in the loft. With the direct cold water supply on the other hand, cold water supply for fittings and taps within a house, comes directly from the rising mains.

Cold Water Supply

Indirect System

When it comes to the indirect cold water supply, there is normally only one permitted connection to the rising main and that is the one going to the cold water tap in the kitchen. In some houses there could be an existing connection to the WC as well. As a home owner, you are allowed to make connections off the cold water supply branch in the kitchen and this could be to an outside tap or for the plumbing to a washing machine. You do however have to use water regulated and approved fittings and valves. If you connect a washing machine to the cold water supply from the rising main, it should be at the mains pressure. Hot water supply should be at the lower pressure.


Other Connections

You might also want to make a connection to the rising main if you have an electric shower or an instantaneous gas water heather as these need mains pressure. The same thing goes for any conditioner, filter or softener devices that change the quality of water. It could be good to know that the rising main, travels up inside a house to a large water cistern in the loft. Some people call this a water tank but technically, a tank is under pressure and closed on all sides. A cistern on the other hand, is open at the top. A cold water cistern is basically a large cylinder that stores water and provides the rest of the house with water. Water tanks and cisterns can be moved if needed, but this is definitely a job for your local plumber.