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Halstead Heat Exchanger (PHE28)
These genuine plate heat exchangers are produced specifically for the boiler manufacturer Halstead. They 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 plate being fully tested for leakage and dimensional accuracy before being packed.
The plate heat exchangers used on the Halstead Finest boilers have the Halstead part number 450985 and are identified by Ezypart with the reference PHE28.
The plate heat exchanger is a key component within the overall function of the boiler, being utilised 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 plate heat exchanger is the item that transfers heat from the primary water circuit in the boiler to the domestic water, achieving a controlled and comfortable level of tap water for use around the home.
The plate heat comprises a stack of a number of rectangular stainless steel plates. Each plate is embossed with linear indentations according to a specially designed pattern that hold the plates apart by a specific distance. The subsequent gaps between the plates are used as water flow channels. All of the edges of all of the plates have folded lip so that water is prevented from spilling out of the edge of the stack of plates. The plates are brazed together at these folded edges creating a leak-free and pressure retaining stack.
On the outside of the top plate there are four connection points. Two of these are for the boiler primary water and the other two are for the domestic water, each pair comprising an inlet and an outlet. The connections are also made of corrosion resistant stainless steel and are specially designed and machined to mate with the connecting components within the boiler. The primary water that is heated by the flame from the burner in the main heat exchanger flows into the plate heat exchanger when there is a call for domestic hot water. This water flows between every other gap between the plates of the stack and leaves from the other connection. At the same time, domestic water enters the plate heat exchanger stack and flows between the other gaps in the stack. In this way, the heat energy contained in the primary water is transferred to the domestic water so that it leaves the heat exchanger at the desired higher temperature. As well as maintaining the correct space between the plates, the embossed indentations also ensure that the primary and the domestic water flows through the gaps in the optimum way, thereby maximising the heat transfer.