Clearly regulated by the standards, but in practice still far from being the rule: heating and drinking water must be kept separate. According to the drinking water ordinance, EN 1717 and DIN 1988-100, the unsecured connection of the heating circuit to the drinking water network is not permitted.
Simple filling with a hose without a safety device is a thing of the past. This is what the standards say. And also every satisfied customer who appreciates the convenience and safety of a high-quality filling fitting.