The pump cannot maintain steady backpressure. In some cases, one pump head works and the other does not.
- It’s likely that the check valves are not working properly. The valves should be removed and cleaned or replaced
- The pump may not be completely primed. The buffer reservoir should be set above the pump inlet and the buffer should be forced through the pump with a syringe. In some cases, using an alcohol such as ethanol or isopropanol will remove air more quickly since the air will dissolve into the alcohol more easily
- Occasionally, some small backpressure is required after the pump to properly seat the outlet check valve. A flow restrictor is used for this purpose