Identifying your plumbing system

Hot cold gravity

Cold water tank is normally located in the loft feeding a hot water cylinder usually in an airing cupboard.

Hot gravity, cold mains

Cold water tank is normally located in the loft feeding a hot water cylinder usually in an airing cupboard. However it differs from the hot and cold gravity system as cold water comes direct from the mains causing an imbalance in pressures. Pressure imbalances of greater than a ratio of 5:1 will require a pressure reducing valve to be installed on the dominant supply when using a mixer.

Hot cold gravity, pump assisted

Cold water tank is normally located in the loft feeding a hot water cylinder usually in an airing cupboard. Both supplies are then pumped to provide a higher volume of water.

Unvented (pressurised system)

Cold water is fed direct from the mains whilst also pressurising hot water cylinder, again usually found in an airing cupboard.

Combination boiler

Boiler can be found anywhere (normally in kitchen) and heats water as you use it. Fed by the mains, hot and cold water are balanced to feed fittings. This system does not require a hot water cylinder or cold water tank and also heats water for the central heating.