Tap Pressure Explained
What is the difference between a high and low pressure?
UK homes generally have one of two main types of hot water system - pressurised and non-pressurised, so before purchasing a tap it is important to find out which system is fitted in your kitchen.
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Pressurised water systems come in two different versions:
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High Pressure Water Systems are usually modern combi boilers or gas water heaters that give you a continuous flow of hot water. If your home has this system you are likely to have a boiler unit but no hot water cylinder or storage tank.
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High Pressure Pumped Water Systems consist of a hot water cylinder with an expansion vessel on top – brands include companies like Megaflo. These cylinders form what is known as an unvented system which is pressurised to mains water pressure, ensuring a strong flow of hot water when you turn a tap on in the home, regardless of where it is located. These are usually found in the airing cupboard and with this system you would usually not have a cold water tank.
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Non-pressurised water systems – occasionally referred to as Gravity fed systems – usually have a cold water tank in the attic and the hot water tank in the airing cupboard.
What happens if I fit the wrong type of kitchen tap?
If you install a tap that requires a pressurised water system and your system is non-pressurised (gravity fed), you will have an extremely weak flow of hot water; sometimes the flow is too weak to enable the tap to supply water at all.
Homes that have a low-pressure water system require specific low-pressure kitchen mixer taps that are designed to operate under lower pressures, ensuring a steady flow of water.
Alternatively, homes that have a high-pressure water system are generally able to use any kitchen tap and will still have a steady flow of water.
If you are unsure about the type of system you have, or what type of kitchen tap will be suitable for your home, it is a good idea to enlist the help of a plumber who can easily identify what you need.
