Hot Water Cylinders


There are two types of hot water cylinders to be used in conjunction with a Boiler and central heating system :

Vented Cylinders :

These can be heated directly with the use of an electric immersion heater, or indirectly using your boiler/ controls to heat the water within the cylinder.

The electric immersion heater can be used as back up heating of hot water if the boiler breaks down.

All new vented hot water cylinders are ‘pre-lagged’ to provide insulation to prevent heat loss and improve efficiency.

Older vented hot water cylinders may have an ‘insulation jacket’ fitted around the cylinder.  There will be increased heat loss from water temperature, so we would recommend considering replacing this type of cylinder for a more efficient new pre-lagged type.

Vented cylinders are gravity fed from a water storage tank sited above the cylinder, generally in the loft area above.  The height of this water storage tank or ‘head height’ is what governs the pressure to the hot water outlets.  Poor hot water pressure to showers etc can be overcome by use of pumps.  If this is in your property, then it may be time to consider changing the hot water cylinder to an unvented type – see below.

 Unvented Cylinders:

These are directly fed by the cold water main.  They are operated by mains pressure and offer much better flow rates so therefore no additional shower pumps would be required.  In addition there is no need for separate cold water storage tank and this would free up space.  If the cold water tank is sited in the loft, removing this would take away the risk of freezing in the winter.

Unvented Cylinders require the use of manufacturer’s safety components to be fitted and therefore MUST be installed by specialists who hold a qualification with G3 Building Regulations.

 ALL Ward Gas Engineers hold the relevant G3 Qualification to carry out installation, servicing and maintenance of vented and unvented hot water cylinders.

 There is a legal requirement that all new hot water cylinder installations need to be notified to Gas Safe or Building Control following completion.