What is a diverter valve?
A diverter valve is a mechanism in a combi boiler that opens or closes to direct hot water either to radiators or taps and showers. Diverter valves are not found in system or conventional boilers because the valve is only needed in boilers where water is heated on demand, whereas system and conventional boilers store hot water in a storage cylinder.
If a specific hot water tap is turned on, the combi boiler will heat water and the valve will direct the hot water to the tap rather than to the home’s radiators or other taps. If the heating is turned on, the combi boiler will do the same for the radiators. If the heating is on and someone turns on the hot tap in the shower, the diverter valve will prioritise sending hot water to the shower instead of the radiators until the shower is turned off.