Remeha vent automatic air bleed device spare offers a wide range of high-quality, great value products, providing more choice for quick and easy repairs. This bleed device is designed for use in the heat exchanger section of Remeha's avanta and profile system boilers. The heat exchanger transfers heat from a boiler's burner to water. A primary heat exchanger is found in all boilers, using heat from a burner to raise the temperature of the water in the system. A secondary heat exchanger is present only in combis and allows the heat to be transferred between closed systems.