What is a vacuum valve? When is it required? A vacuum valve (part number 569-00065-00) is a required accessory for the Heidolph Hei-VAP Expert Control and Ultimate Control when used with one of the following vacuum sources: valve-regulated vacuum pump (not a Heidolph Vario pump) house vacuum The Hei-VAP Expert Control and Ultimate Control contain an integrated vacuum controller (the ‘brains’), but you need to purchase the vacuum valve if you are not using a Heidolph Vario pump, as the valve is what opens and closes in order to regulate the vacuum. For optimal vacuum control, a Heidolph Vario vacuum pump is recommended instead: Hei-VAC (Rotavac) Vario Tec (12 mbar) Hei-VAC (Rotavac) Vario Control (2 mbar) In this case you wouldn’t need the vacuum valve as the Hei-VAP communicates with the pump to adjust its speed and regulate the vacuum.