Little or no flow to water dispenser.

Adding a small amount of water to the filter would resolve the problem for a week or two. So, I thought this was an issue with the filter and decided to try the bypass cap to help zero in on the problem. The bypass cap had no instructions concerning the need for O ring so it was trial and error. The O ring was not needed. After installation of the bypass cap, no water flow resulted and I had to replace the filter. Intermittent problem continues.