These cylinders are supplied with cold water directly from the rising main of your home.
Therefore, hot water is delivered to the outlets at mains pressure. No pump needed!
Vented Hot Water Cylinders
These are traditional hot water tanks, sometimes referred to as the ‘immersion heater’.
They are supplied with cold water from a tank in the loft (cold water storage cistern), and are heated by the boiler with an electrical backup (immersion heater) which can be used in the event of a boiler breakdown.
The most complained about issue with these cylinders is low hot water pressure at the outlets (taps & showers).
This is because the system relies on gravity (and good pipework) to deliver the flow of hot water. The higher the cold water storage cistern is above the cylinder, the greater the flow at the outlets.
Problems can be overcome by fitting a pump…or upgrading to an unvented cylinder….