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Hydraulic diverter valve for Ariston Styx SX20 Euro combination boiler.
These genuine model V35 diverter valves are produced by the Italian company Giannoni, who is a specialist in this field. The valves are of a well-proven design, with hundreds of thousands being installed in combi boilers all over Europe. They are manufactured under strict quality controlled conditions, each and every valve being fully tested for leakage and operation before being packed.
The diverter valves used on the Ariston Styx SX20 Eurocombi, SX20, DIA 20, DIA 24 and Challenger 80E boilers have the Ariston part number 560166 and are identified by Ezypart with the reference DV025.
The diverter valve performs a critical function within the overall operation of the boiler, being activated every time there is a demand for domestic hot water. One of the main advantages of these combination boilers is that they provide domestic hot water at mains pressure, eliminating the need for cold water tanks and shower booster pumps. The diverter valve is the component within the boiler that responds when a hot water tap is opened and diverts primary (heating) water to a heat exchanger in which the mains pressure domestic water is heated to a comfortable level.
The valve comprises a brass body with five water connections. On the diaphragm chamber, identified by the eight screws clamping the two parts together, there are two ½” externally threaded domestic water inlet/outlet connections. The inlet, which includes a filter to prevent contamination by dirt, is connected to the incoming mains cold water supply. The outlet is close-coupled to a secondary heat exchanger, and features an adjustable flow regulator.
The shaft or spindle projects from the centre of the diaphragm chamber and is fitted with black plastic pusher disc that presses on the microswitches when the valve is actuated. Inside this chamber there is the flexible rubber diaphragm, mounted on stainless steel discs, retained in the correct position by carefully selected springs. The diaphragm is made from ethylene propylene WRAS (Water Research Advisory Service) or WRC (Water Research Council) approved rubber, specifically selected to comply with the UK water regulations. The stainless steel shaft is located in PTFE bearings that contain rubber O-rings that ensure no leakage.
The primary body of the valve includes a ¾” primary water inlet connection and two primary (heating) water outlet connections. In the winter, the heating water flows through the 1” externally threaded outlet connection when the valve is in the non-actuated position, and this heating water is discharged into the central heating system and circulated around the heating system before it returns to the boiler, where it re-enters the main heat exchanger. When there is a demand for domestic hot water, the cold mains water entering and leaving the diaphragm chamber causes the valve to change position. Now the heating water flows through the ¾” externally threaded primary water outlet connection to be passed to the close-coupled secondary domestic hot water heat exchanger. In the summer, there is no flow of primary water until the boiler detects a requirement for domestic hot water.
Supplied with full set of washers.