Is the pressure only low at kitchen sink, if so we had the same problem. It turned out to be a small piece of debris in the faucet itself. Not in the strainer, but actually in the faucet, the faucet had to be taken out and debris found. It was very difficult because when we used the water pump pressure was pretty good, because the more pressure the more it pressed the debris and slowed flow. After the dealer figured it out it worked fine.