A bypass for the pump
The development of a bypass valve was a further mile stone on the path to the ideal pump. This differential pressure valve is installed in the heating circuit between the feed and return lines to ensure mechanical influence of the hydraulics. If, for example, the pressure of the moving water becomes too high, the bypass valve is activated to compensate the pressure.
In the early days of central heating systems, the circulators were not yet adjusted optimally. At that time, the precise dimensioning of the heating system was still very time-consuming and costly. Oversized pumps were therefore used in many cases in order to ensure sufficient heat requirements. The unpleasant noises created by the delivery head were reduced considerably after the introduction of the bypass valve in 1968.
Opening the new component lowered the delivery head in the heating system and reduced the noise. The delivery volume of the pump could be adjusted continuously to 0, depending on the user’s needs. A low value was usually sufficient for ensuring the performance of the heating. In the event that the circulator did not transport enough hot water from the boiler to the radiators and the rooms did not reach the desired temperature, the delivery volume could be readjusted by setting the bypass valve to a higher value. This mechanical approach was also a good solution for reducing heating costs. Until then, the heating pumps did not only operate independently of the actual need, but even when the heating was not even in operation, which was unnecessary.
The more needs-based supply of the radiators by means of a bypass valve ensured the improved heat use of the rooms while also reducing the waste of resources. Since the bypass valve barely reduced the power consumption of the pump, this offered only a limited savings potential. Other solutions had to be developed in order to achieve an energy-efficient power adjustment.
However, roughly another decade was to pass, during which Wilo initially concentrated on new business areas, before the multi-speed switch for the further optimisation of pump technology was introduced.