CT Pro Regen 3.0 Bar Twin Positive Brass Shower Pump

If you live in an older property, there is a good chance you have a gravity fed system. Renowned for poor water pressure and flow.

A gravity fed system consists of a large cold water storage tank usually located in the loft and a hot water cylinder located in an airing cupboard. These systems rely on gravity to force water around the system, with the height of the cold-water storage tank determining the pressure throughout the system.

Cold water is delivered to a cold-water storage tank from the water mains. Cold water from the cold-water storage tank is then supplied to the outlets around the system, such as taps, toilets, showers and baths. Once an outlet requiring hot water is opened, gravity will force cold water from the cold-water storage tank into the hot water cylinder, this will then force hot water out from the top of the cylinder, delivering hot water to the open outlet.

Watch our video on gravity fed systems.

A gravity-fed system is either positive or negative head. In a positive head system a water flow rate of at least 2L/min exists from gravity alone. In negative head systems the water flow rate is less than 2L/min.

When choosing which pump you need it is important to know if the system is positive or negative head as incorrect selection can mean the pump won’t work.

A positive head pump will only work in a positive head system and a negative head (universal) pump will work in both a positive and negative head system, so if you are not sure choose a negative head pump.

A positive head pump will activate when a minimum flow of water passes through the pump and out of the pumped outlet, such as a shower or tap, naturally (without assistance from the pump). The minimum flow rate required for our positive head pumps is 2 litres of water per minute (L/min).

You will need to measure the flow rate to determine if a positive head pump is suitable for your system. You will need to test all outlets, such as showers and taps, that are going to be pumped to determine if they have the required minimum flow rate of 2L/min. Watch our video to learn how to measure the water flow rate.

If you cannot measure the water flow rate, then you can check if the system is suitable for a positive head pump if there is more than 600 mm between the base of the cold-water storage tank and the highest point in the system after the pump.

If you are unable to achieve the minimum flow rate of 1 litre per 30 seconds from all outlets that are to be pumped you will need to install a negative (universal) head pump.

Twin pumps have two impellers and are designed to supply both hot and cold water to showers, bathrooms and whole house installations.