Hot Water Cylinders

Unvented & Vented Hot Water Cylinders

Cylinders are manufactured in two different styles – unvented cylinders and vented cylinders. An unvented cylinder works off the mains water pressure to feed into your hot water system. An unvented cylinder is the type you will find in your loft. Also known as a “gravity-fed hot water system”, these cylinders use gravity to supply hot water throughout your home.

Indirect & Direct Hot Water Cylinders

Separate from vented or unvented types of hot water cylinders, you can also choose between direct or indirect cylinders. This describes the method by which the water is heated inside the cylinder.

Direct hot water cylinders heat the water inside via two immersion heaters. The one on the bottom of the cylinder heats the water to temperature while the other heater maintains it ready for use.

The other type of hot water cylinder is the indirect type. Indirect cylinders will be equipped with either a copper coil or airlock inside (depending on the type of heating system you have) and a thermostat attached to the outside of the shell. When the thermostat requests for the water to be heated, existing hot water will be pumped through the inside of the cylinder, passing the heat through to the water, which is then pumped out to wherever you need it.