Please do the following troubleshooting steps which pertain to your breast pump suction power:

1. Make sure that the membrane & valve are installed correctly and attached properly. There should be a tiny slot on the valve to fasten the membrane.
2. Make sure that the membrane fits the valve body snugly. There should be a tiny slot on the valve to fasten the membrane securely to the valve. Please note that frequent use or improper sterilization method can cause aging on the membrane. If the membrane has aged and worn out, this will result to leaks, chips, cracks or holes which affect the suction performance. If you notice aging on the membrane, please replace it with a new one. (Your Breast Pump should come with extra membranes. Replacement Parts are also available at www.bellema-usa.com)
3. Make sure that the silicone cushion on each pump fits tightly unto the breast shield. The silicone cushions have edges that should mould perfectly across the flange edges. Make sure both edges of the silicone cushion and the flange are fastened together perfectly.
4. Make sure that the damper, which is located under the lid of the flange is properly attached to the grid. Check on the cap plug (the small round plastic attached on the round inner ring of the lid) and make sure it is attached tightly. Make sure that there are no water drops on all the parts inside the damper cap or lid. The parts inside the flange cap or lid such as: cap plug, grid and the seal ring must be dry with no water drops.
5. Check the tubing making sure that it is not kinked, bent or twisted. The tubing must be straightened to ensure proper air flow. If you notice water condensation or milk inside the tubing, clean and air dry. The tubing must always be dry and checked every each use.
6. Check to make sure the flange is well secured and tightly fastened to the tubing. If you are using a Battery Pack, make sure that it is fully charged (M Series).