There are two different types of heat exchanger that can be fitted, the primary heat exchanger and the secondary heat exchanger. The primary is present in almost all boilers and uses heat from the burner to raise the temperature of water within the system. The secondary heat exchanger is exclusive to combination boilers and allows the heat to be transferred between one closed system and another.
This part is present in 11 different boilers in the Vokera range
![Vokera Heat Exchanger Domestic 8037 [2790]](http://allgasltd.com/cdn/shop/files/Screenshot2023-05-11at13.58.47.png?v=1683810498&width=1445)