The Baxi spare part for combi condensing boilers is the Baxi plate heat exchanger kit. A boiler's burner heats the water through the heat exchanger. While a secondary heat exchanger is only found in combi boilers and allows heat to be transported between closed systems, a primary heat exchanger is present in all boilers and uses heat from a burner to raise the temperature of the water in the system.

Brand Name	Baxi