If your bottle leaks at the point where it connects to the connector, or the milk stagnates around the flange without going down into the container, check that you have a small silicone O-ring around your connector and that it's securely in place.
If it is not, you can find a spare joint in the accessory bag in the pump's box. It is this joint that ensures the seal between the bottle and the connector and prevents the milk from flowing between the two.
You can also check your alignment:
- Are all parts fitted snugly together?
- Is the diaphragm pressed firmly into the back of the hub?
- Did you maybe forget to put the duckbill valve?
- Are the holes at the end of the flange lined up top and bottom like they should be?
Refer to this article to make sure you're perfectly assembling your Perifit Pump.