The bypass valve in a hydraulic filter head is a safety protection device. When the filter element becomes severely clogged and the differential pressure reaches the set value (typically 2.1 bar or 3.5 bar), the bypass valve automatically opens, allowing some oil to pass through without being filtered. This prevents the filter element from collapsing and avoids system oil starvation. However, once the bypass valve opens, contaminants in the system will flow directly into downstream components, accelerating wear. Therefore, as soon as the pressure drop indicator alarms or the bypass valve opens frequently, the machine must be stopped immediately and the filter element replaced. Do not rely on the bypass valve to continue operation.
