Page 29 - Building services book

There are two main types of Hot Water Cylinders: Unvented Hot Water Cylinders and Vented Hot Water
Cylinders. An unvented cylinder is fed water from the mains whereas vented cylinders are fed from a cold water
storage tank.
These two types can be either Direct Cylinders or Indirect Cylinder and refers to the way they heat water. Direct hot

water cylinders heat water directly with an immersion heater fitted into the hot water cylinder. An indirect
hot water cylinder heat’s the water via a heat exchanger which is a coil of pipe that runs through the hot water
cylinder. This coil has hot water from the central heating circuit running through it and the heat from the central
heating system is used to heat the hot water cylinder indirectly. Solar Compatible Cylinders can be fitted to take

advantage of solar energy they work by transferring the heat captured by the solar panel to heat water in the Solar
Hot Water Cylinder. Hot water cylinders can be either Copper Cylinders or Stainless Steel Cylinders and must be
insulated.