Caleffi discalslim deaerator threaded connections 1" f horizontal or vertical installationCaleffi DISCALSLIM deaerator 1" F threaded connections for horizontal or vertical installations Code 551806 The deaerator is a device that uses the degassing process to transform the air that forms in the circuits of heating systems into micro bubbles and then slowly and continuously discharge it outside. Thus it allows to always have a system free from air formations inside, therefore more functional, less noisy, free from localized overheating,