Choosing the Correct Home Water Pump

Choosing the correct water pump for your home can depend on various factors, are you looking to power a single shower, multiple bathrooms or a whole house? It also depends on the type of heating and hot water system that you have in your house. First, we will briefly explain the 3 main hot water systems.

Three Main Hot Water Systems

The three main water systems used in the UK are: gravity fed systems, combination boiler systems and unvented systems.

Gravity Fed – Gravity fed systems consist of a water tank in the loft and a hot water cylinder which is often placed on the top floor in an airing cupboard

Combination Boiler – Hot water is produced on demand by a small wall hung boiler, no water tank is needed to store the cold water as the boiler is fed straight from the mains water supply.

Unvented – Unvented systems use a wall hung boiler and a metal clad water tank, no cold-water tank is needed.

Where is Your Cold-Water Tank Positioned?

On gravity fed systems, the position of your water tank compared to your pipework depends whether your system is positive or negative (universal) head. This affects which water pump you will need for your home, here is a brief explanation of positive and negative head.

Positive Head – This system is designed to be gravity fed so needs a certain distance , specified by the manufacturer, between the bottom of the water tank and the water pump. Gravity pulls the water to the pump and kick-starts it to push the water through to your shower, tap, etc.

Negative Head – If your pump is situated inline or above your water thank then it is a ‘negative head’ system. The water is sucked through from the tank, through the pump and to your shower, tap, etc. This system is more common in flats.

Shower Head Size

The size of your shower head can also affect the type of pump that you will need, here is a rough guide:

Shower Head Diameter up to 5cm – 1.5 bar

Shower Head Diameter up to 5-10cm – 2.0 bar

Shower Head Diameter up to 10-12.5cm – 2.5 bar

Shower Head Diameter more than 12.5cm – 3.0 bar

How Many Appliances Will You Be Powering?

Water pumps pressure is rated in ‘bar’ 1.0 bar is equal to the pressure exerted by 10 metres of gravity fed water, the higher the number the greater the pressure. Choosing the correct pressure can depend on how many appliances you will be powering with the pump, here is a rough idea:

1.5 bar pressure – for one shower, tap or appliance

2.0 bar pressure – for two or three showers, taps or appliances or a bathroom

3.0 bar pressure – for the whole house.

Salamander Pumps have a very useful pump selector to help you pick the right pump, find it HERE >>

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