Motorised valves: ie open or closed to the flow of hot water.

Both 2 and 3 port motorised valves are used and the choice depends on the application, pipe work layout and preference. Two port valves are the most commonly used for the control of separate heating and hot water zones. Three port valves are suitable for providing separate heating and hot water circuits. There are two types of 3 port valves, one type only diverts the flow of water whilst the other provides a mid position, providing shared flow to both heating and hot water. More than one heating zone - in addition to a hot water zone use a separate 2 port valve for each additional zone. Auxiliary switches on the motorises valve should be wired to switch the boiler/pump on and then off when there is no demand for heating or hot water, providing boiler interlock and complying to building regulations.

The 2 port motorised valve is the most common product used and they do give better performance than the 3 port motorised valves by being able to make full use of the heat from the boiler. They also are essential for zoning the heating and hot water systems, giving more control. These are linked to the boiler via room or programmable room thermostat on heating and cylinder thermostat for hot water. The use of controls will make substantial savings on fuel bills when wired to the boiler to give full control.