What Are The Benefits
A conventional hot water cylinder uses water from a cold feed tank, supplied to the cylinder at low pressure, giving a low pressure hot supply.
By utilising mains pressure cold water, in an unvented cylinder, all hot supply is pressurised up to the working limit of the cylinder, normally, for stainless steel, approx 3.0 bar. This gives excellent showers directly from the cylinder, without need to provide pumps.
What Special Arrangements Are Required
Because the unit will use mechanical valves which can discharge very hot water at high pressure, a safe route out for a discharge pipe is the prime requisite. This pipe should be able to terminate in a place where it can not be accessed by the occupants.
If the unit is Horizontal in the loft, ensure the full weight of the cylinder can be supported.
Who Can Install Them
They should only be installed by plumbers who hold a Certificate of Competence to install unvented units, to comply with Building Regulations G3.
What Maintenance Is Required
Annual maintenance is required on the valves and expansion Vessel, to maintain safety and working life of the cylinder, failure to maintain will invalidate warranty.
Hot Water Cylinders Size And Capacity
Cylinders can be manufactured to fit a restricted space and / or to contain a specified capacity, in litres.
Remember to allow for insulation which is additional to the ‘bare metal’ sizes shown below.
Foam insulation adds approx 50mm overall, casing adds approx 80mm.
